(n°1) Green Tea (Camellia Sinensis) Mediated Suppression of IgE Production By Peripheral Blood Mononuclear Cells of Allergic Asthmatic Humans.
Wu SY, Silverberg JI, Joks R, Durkin HG, Smith-Norowitz TA., Scand J Immunol. 2012 Sep;76(3):306-10. doi: 10.1111/j.1365-3083.2012.02729.x, State University of New York, Brooklyn, NY, USA.
Recent studies in our laboratory demonstrated the suppression of immunoglobulin E (IgE) production by green tea extract (GTE) in U266 cells. However, the effects of GTE or one of its components (EGCG) on IgE production by human peripheral blood mononuclear cells (PBMC) are unknown. This study demonstrates that GTE and its major catechin, EGCG, have immunoregulatory effects on human IgE responses.
(n°2) Effects of the aqueous extract of white tea (Camellia Sinensis) in a streptozotocin-induced diabetes model of rats.
Islam MS, Phytomedicine. 2011 Dec 15;19(1):25-31. Epub 2011 Jul 30, University of KwaZulu-Natal, Durban, South Africa.
White tea (WT) is very similar to green tea (GT) but it is exceptionally prepared only from the buds and young tea leaves of Camellia Sinensis plant while GT is prepared from the matured tea leaves. The present study was investigated to examine the effects of a 0.5% aqueous extract of WT in a streptozotocin-induced diabetes model of rats. Data of this study suggest that the 0.5% aqueous extract of WT is effective to reduce most of the diabetes associated abnormalities in a steptozotocin-induced diabetes model of rats.
(n°3) Green tea (Camellia Sinensis) suppresses B cell production of IgE without inducing apoptosis.
Hassanain E, Silverberg JI, Norowitz KB, Chice S, Bluth MH, Brody N, Joks R, Durkin HG, Smith-Norowitz TA., Ann Clin Lab Sci. 2010 Spring;40(2):135-43, State University of New York Downstate Medical Center, Brooklyn, USA
Green tea (Camellia Sinensis) is known to possess biological properties that are antioxidative and antimutagenic. Recent studies demonstrated beneficial effects of green tea in inflammatory allergy. However, the effect of green tea on anti-allergic activity/IgE responses in vitro has not been studied. The suppression was dose-dependent with the highest concentrations resulting in the greatest suppression. The suppression of IgE production by green tea extract was not mediated by apoptosis or cell death. This study demonstrates that green tea extract has immunoregulatory effects on human IgE responses in vitro.
(n°4) Study on the theraputic effect of plants of Camellia genus on osteoporosis
Tang L, Feng BM, Shi LY, Wu XJ, Shi HB, Miao YB, Wang YQ, Zhong Yao Cai. 2008 Oct;31(10):1540-4, Dalian University, Dalian, China.
To observe anti-osteoporotic effect of Plants of Camellia genus induced by retinoic acid in rats, in adqulis crude drug dosage, and to compare activities of them. The results of this study indicated that effects of ethanol extracts of seed from Camellia japonica on anti-osteoporosis with retinoic acid were the strongest. Ethanol extracts of seed from Camellia japonica , ethanol extracts of leaves from Camellia Oleifera, and aqueous extracts of leaves from Camellia Oleifera were stronger than positive control drug. The other extracts didnt show obvious anti-osteoporotic effects. Eventually the strength order of each group on anti-osteoporosis was as following: ethanol extracts of seed from Camellia japonica > ethanol extracts of leaves from Camellia Oleifera > aqueous extracts of leaves from Camellia Oleifera > aqueous extracts of seed from Camellia Oleifera > positive control drug > aqueous extracts of seed from Camellia Japonica. Plants of Camellia genus have different degree anti-osteoporosis effect, which can offer significant theory basis for progressive investigation and exploitation of them.
(n° 5) Phenolic antioxidants identified by ESI-MS from Yerba maté (Ilex paraguariensis) and green tea (Camellia Sinensis) extracts.
Bastos DH, Saldanha LA, Catharino RR, Sawaya AC, Cunha IB, Carvalho PO, Eberlin MN, Molecules. 2007 Mar 12;12(3):423-32, São Paulo University, São Paulo, Brazil.
Aqueous extracts of green yerba maté (Ilex paraguariensis) and green tea (Camellia Sinensis) are good sources of phenolic antioxidants, as already described in the literature. The subject of this study were organic extracts from yerba maté, both green and roasted, and from green tea. Organic extracts containing phenolic antioxidants might be used as natural antioxidants by the food industry, replacing the synthetic phenolic additives used nowadays. The ether extracts from green and roasted yerba maté displayed a weak scavenging activity, different from the behavior observed for the green tea ether extract. The main phenolic compounds identified in green yerba maté water and ethanolic extracts were: caffeic acid, quinic acid, caffeoyl glucose, caffeoylquinic acid, feruloylquinic acid, dicaffeoylquinic acid and rutin. After the roasting process two new compounds were formed: caffeoylshikimic acid and dicaffeoylshikimic acid. The ethanolic extracts from yerba maté, both roasted and green, with lower content of phenolic compounds (3.80 and 2.83 mg/mL) presented high antioxidant activity and even at very low phenolic concentrations, ether extract from GT (0.07 mg/mL) inhibited DPPH over 90%.
(n°6) Anti-Inflammatory Effects of a Polyphenols-Rich Extract from Tea (Camellia Sinensis) Flowers in Acute and Chronic Mice Models.
Chen BT, Li WX, He RR, Li YF, Tsoi B, Zhai YJ, Kurihara H., Oxid Med Cell Longev. 2012;2012:537923. Epub 2012 Jul 30., Jinan University, Guangzhou, China
While beneficial health properties of tea leaves have been extensively studied, less attention is paid to the flowers of tea. In this study, the anti-inflammatory effects of hot water extract of tea (Camellia Sinensis) flowers were investigated. These results indicated that tea flowers had potent anti-inflammatory effects on acute and immunological inflammation in vivo, and may be used as a functional natural food.
(n° 7) Green tea extract: Possible mechanism and antibacterial activity on skin pathogens.
Sharma A, Gupta S, Sarethy IP, Dang S, Gabrani R., Food Chem. 2012 Nov 15;135(2):672-5. Epub 2012 May 11., Jaypee Institute of Information Technology, Noida, India.
Camellia Sinensis (tea) is known for its therapeutic properties (anti-inflammatory, anti-microbial, anti-tumour, anti-oxidative and anti-ageing). Although, anti-microbial properties of green tea have been studied, its role against bacterial strains related to skin infections and mechanism of action is not well understood. We focussed on exploring anti-microbial activity and the basic mechanism of aqueous green tea leaf extract on selected bacterial strains. Staphylococcus epidermidis, Micrococcus luteus, Brevibacterium linens, Pseudomonas fluorescens and Bacillus subtilis were found to be sensitive to green tea extract via disc diffusion assay (zone of inhibition ⩾7mm). Minimal inhibitory concentration (MIC) was determined via nitro blue tetrazolium (NBT) assay (0.156-0.313mg/ml). Moreover, the aqueous extract was found to be not toxic to the Vero cell-line up to a concentration of 500μg/ml. The effect of aqueous extract on adhesion of different bacteria to Vero cells indicated that it inhibits the adhesion at its MIC value.
(n° 8) Novel approaches to chemoprevention of skin cancer.
Bickers DR, Athar M., J Dermatol. 2000 Nov;27(11):691-5., Columbia Medical Center, 161 Fort Washington Avenue, New York, NY 10032, USA.
Protection against sun-induced damage leading to photocarcinogenesis in skin is a highly desirable goal. Among various strategies, chemopreventive approaches utilizing non-toxic agents to prevent the occurrence of precancerous lesions or their surrogate markers are potentially attractive. Epidemiological and experimental studies provide evidence that some naturally occurring chemical agents in the human diet can diminish cancer risk. Aside from water, tea is the most common beverage consumed worldwide. Black tea accounts for nearly 80% of total tea production. Black tea and green tea are derived from the same plant, Camellia Sinensis. Green tea contains monomeric polyphenols known as flavanols and black tea contains dimeric flavanols and polymeric polyphenols known as theaflavins (TFs) and thearubigins (TRs). In summary, these studies indicate that tea extracts are effective in reducing UVB- and PUVA-mediated DNA damage, expression of early response genes and early inflammatory changes in skin. These studies verify a conceptual rationale for employing naturally occurring dietary constitutents as an approach to cancer chemoprevention.
(n° 9) Antioxidant Activities of Extracts from Teas Prepared from Medicinal Plants, Morus alba L., Camellia Sinensis L. and Cudrania tricuspidata and Their Volatile Components.
Nam S, Jang HW, Shibamoto T., Agric Food Chem. 2012 Aug 7.
The antioxidant activity of essences of teas prepared from mulberry (Morus alba L.), Camellia Sinensis L., and Cudrania tricuspidata (Carr.) Burea plant was examined using two antioxidant assays. These results suggest that consumption of antioxidant-rich beverages prepared from these plants may be beneficial to human health.
(n° 10) Green tea extract: Possible mechanism and antibacterial activity on skin pathogens.
Sharma A, Gupta S, Sarethy IP, Dang S, Gabrani R., Food Chem. 2012 Nov 15;135(2):672-5. Epub 2012 May 11., Jaypee Institute of Information Technology, Noida, India.
Camellia Sinensis (tea) is known for its therapeutic properties (anti-inflammatory, anti-microbial, anti-tumour, anti-oxidative and anti-ageing). Although, anti-microbial properties of green tea have been studied, its role against bacterial strains related to skin infections and mechanism of action is not well understood. We focussed on exploring anti-microbial activity and the basic mechanism of aqueous green tea leaf extract on selected bacterial strains. Staphylococcus epidermidis, Micrococcus luteus, Brevibacterium linens, Pseudomonas fluorescens and Bacillus subtilis were found to be sensitive to green tea extract via disc diffusion assay (zone of inhibition ⩾7mm). Minimal inhibitory concentration (MIC) was determined via nitro blue tetrazolium (NBT) assay (0.156-0.313mg/ml). Moreover, the aqueous extract was found to be not toxic to the Vero cell-line up to a concentration of 500μg/ml. The effect of aqueous extract on adhesion of different bacteria to Vero cells indicated that it inhibits the adhesion at its MIC value.
(n° 11) Green Tea Polyphenols for the Protection against Renal Damage Caused by Oxidative Stress.
Yokozawa T, Noh JS, Park CH., Evid Based Complement Alternat Med. 2012;2012:845917. Epub 2012 Jul 10., University of Toyama, Toyama, Japan.
Green tea, prepared from the leaves of Camellia Sinensis L., is a beverage that is popular worldwide. Polyphenols in green tea have been receiving much attention as potential compounds for the maintenance of human health due to their varied biological activity and low toxicity. In particular, the contribution of antioxidant activity to the prevention of diseases caused by oxidative stress has been focused upon. Our observations suggest that green tea polyphenols have a beneficial effect on pathological states related to oxidative stress of the kidney.
(n° 12) Evaluation of anti-inflammatory effects of green tea and black tea: A comparative in vitro study.
Chatterjee P, Chandra S, Dey P, Bhattacharya S., J Adv Pharm Technol Res. 2012 Apr;3(2):136-8., Bengal School of Technology, West Bengal, India.
The present study was conducted to evaluate and compare the anti-inflammatory effects of aqueous extracts of green tea and black tea leaves (Camellia Sinensis) against the denaturation of protein in vitro. From the present findings it can be concluded that both green and black tea leaves possessed a marked anti-inflammatory effect against the denaturation of protein, in vitro. Green tea was found to be more active than black tea, plausibly due to the higher flavonoid contents of green tea.
(n° 13) Natural products: A safest approach for obesity.
Vasudeva N, Yadav N, Sharma SK., Chin J Integr Med. 2012 Jun;18(6):473-80. Epub 2012 Jul 22., University of Science and Technology, Hisar, Haryana, India
Obesity is recognized as a social problem, associated with serious health risks and increased mortality. This review focuses on the medicinal plants such as Achyranthus aspera, Camellia Sinensis, Emblica officinalis, Garcinia cambogia, Terminalia arjuna, etc., being used traditionally in Ayurvedic, Unani, Siddha and Chinese, etc., systems of medicine. The review also highlights recent reported phytochemicals such as escins, perennisosides, dioscin, gracillin, etc., and the various extracts of the plants like Nelumbo nucifera, Panax japonicas, Cichorium intybus, Cyperus rotundus, Paeonia suffruticosa, etc., which have been successfully identified for the treatment of obesity.
(n° 14) L-Theanine promotes nitric oxide production in endothelial cells through eNOS phosphorylation.
Siamwala JH, Dias PM, Majumder S, Joshi MK, Sinkar VP, Banerjee G, Chatterjee S., J Nutr Biochem. 2012 Jul 20, Anna University, Chennai, India.
Consumption of tea (Camellia Sinensis) improves vascular function and is linked to lowering the risk of cardiovascular disease. Endothelial nitric oxide is the key regulator of vascular functions in endothelium. The results of our experiments are suggestive of l-theanine mediated vascular health benefits of tea.
(n° 15) Tea consumption is inversely associated with weight status and other markers for metabolic syndrome in US adults.
Vernarelli JA, Lambert JD., Eur J Nutr. 2012 Jul 10, The Pennsylvania State University, USA,
Tea (Camellia Sinensis) is a widely consumed beverage, and laboratory and some intervention studies have indicated the potential health benefits of hot tea. Hot tea consumption was associated with beneficial biomarkers of cardiovascular disease risk and inflammation (increased high-density lipoprotein-associated cholesterol and decreased C-reactive protein in both sexes, and reduced triglycerides in women), whereas the association with iced tea consumption was again reversed. These cross-sectional results support growing laboratory data, which demonstrate the negative association of hot tea intake with markers of MetS.
(n° 16) Hepatoprotective and antioxidant activity of standardized herbal extracts.
Hiraganahalli BD, Chinampudur VC, Dethe S, Mundkinajeddu D, Pandre MK, Balachandran J, Agarwal A., Pharmacogn Mag. 2012 Apr;8(30):116-23., R and D Centre, Natural Remedies Pvt. Ltd, Bangalore, India.
Phyllanthus emblica, Camellia Sinensis, Mangifera indica, Punica granatum, and Acacia catechu have been shown to possess widespread pharmacological application against multitude of diseases namely cancer, diabetes, liver disorders, and oxidative stress.We evaluated the hepatoprotective activity of the standardized herbal extracts against tert-butyl hydroperoxide (t-BH) induced toxicity and their mechanism of hepatoprotective action in human hepatocarcinoma cells (HepG2 cell line). The extracts exhibited significant antioxidant property as evident by the Trolox values and effective scavenging of DPPH and ABTS radicals. The extracts also demonstrated inhibition of AAPH-induced fluorescence in HepG2 cells. These results indicate the ability of the plant extracts to protect the liver cells from chemical-induced damage, which might be correlated to their radical scavenging potential.This study demonstrates that these extracts have potential hepatoprotective activity which is mainly attributed to the antioxidant potential, which might occur by reduction of lipid peroxidation and cellular damage.
(n° 17) Medicinal flowers. XXXIII. Anti-hyperlipidemic and anti-hyperglycemic effects of chakasaponins I-III and structure of chakasaponin IV from flower buds of Chinese tea plant (Camellia Sinensis).
Matsuda H, Hamao M, Nakamura S, Kon'i H, Murata M, Yoshikawa M., Kyoto Pharmaceutical University, Kyoto, Japan.
Effects of principal saponins, chakasaponins I-III, from the flower buds of Camellia Sinensis cultivated in Fujian province, China on plasma triglyceride (TG) and glucose levels in olive oil or sucrose-loaded mice were examined. Chakasaponins I-III at 50 and 100 mg/kg significantly inhibited increases in plasma TG and glucose levels. Furthermore, they prevented gastric emptying, suggesting that the former inhibitory effect is partly dependent on the inhibition of gastric emptying. In addition, the chemical structure of a new acylated oleanane-type triterpene oligoglycoside, chakasaponin IV, was elucidated on the basis of chemical and physicochemical evidence.
(n° 18) Triterpene saponins with hyaluronidase inhibitory activity from the seeds of Camellia Sinensis.
Myose M, Warashina T, Miyase T., Chem Pharm Bull (Tokyo). 2012;60(5):612-23, University of Shizuoka, Shizuoka, Japan.
The MeOH extract of the seeds of Camellia Sinensis (L.) KUNTZE gave twelve new saponins (1-12) along with ten known saponins (13-22). These saponins (1-22) showed stronger hyaluronidase inhibitory activity than the positive control, rosmarinic acid.
(n° 19) Herb-drug interactions: an overview of systematic reviews.
Posadzki P, Watson L, Ernst E., Br J Clin Pharmacol. 2012 Jun 1. doi: 10.1111/j.1365-2125.2012.04350.x. [Epub ahead of print]
The aim of this overview of systematic reviews (SRs) is to critically evaluate the evidence regarding interactions between herbal medicinal products (HMPs) and synthetic drugs. The most severe interactions resulted in transplant rejection, delayed emergence from anaesthesia, cardiovascular collapse, renal and liver toxicity, cardiotoxicity, bradycardia, hypovolemic shock, inflammatory reactions with organ fibrosis and death. Moderately severe interactions were noted for ginkgo biloba, panax ginseng, piper methysticum, serenoa repens and camellia Sinensis. The most commonly interacting drugs were antiplatelet agents and anticoagulants. The majority of the HMPs evaluated in SRs were not associated with drug interactions with serious consequences. However, the poor quality and the scarcity of the primary data prevent firm conclusions.
(n° 20) Effect of green tea extract on reactive oxygen species produced by neutrophils from cancer patients.
Suzuki K, Ohno S, Suzuki Y, Ohno Y, Okuyama R, Aruga A, Yamamoto M, Ishihara KO, Nozaki T, Miura S, Yoshioka H, Mori Y., Anticancer Res. 2012 Jun;32(6):2369-75, Waseda University, Saitama, Japan.
Oxidative stress in cancer patients has been demonstrated to be partly mediated by neutrophils. Although it is reported that natural antioxidants, such as green tea extract, reduce oxidative stress, there is limited evidence of their effects in cancer patients. Peripheral blood samples were obtained from eighteen patients with advanced cancer. Green tea extract was added to the blood samples with luminol on Mebiol gel, and luminol-dependent chemiluminescence was measured to monitor the production of reactive oxygen species from migrated neutrophils into the gel, at 37°C. Luminol-dependent chemiluminescence was significantly down-regulated in the presence of green tea extract in a concentration-dependent manner.These results indicate the antioxidant effect of green tea extract on reactive oxygen species produced by neutrophils, which may be effective in reducing oxidative stress in cancer patients.
(n° 21) Changes in skin mechanical properties after long-term application of cream containing green tea extract.
Mahmood T, Akhtar N, Khan BA, Shoaib Khan HM, Saeed T., Aging Clin Exp Res. 2011 Oct-Dec;23(5-6):333-6., The Islamia University of Bahawalpur, Pakistan
We studied longterm application of cream containing green tea extract, to obtain knowledge of its effects on epidermal mechanics by 2-mm diameter Cutometer probe. Using this non-invasive device, we assessed the effects of green tea extract cream on skin mechanical properties. Healthy male volunteers (n=10) were included in this study, which lasted 60 days. Statistically significant (p<0.05) results were notable for the R6 (Uv/Ue) parameter with respect to time (ANOVA); R0, R2 (Ua/Uf) and R7 (Ur/Uf) parameters were found statistically not significant by ANOVA. This study demonstrates that green tea formulation has a certain effect on R6 (Uv/Ue) parameter when applied regularly for a certain period of time. These results indicate that the formulation has no pronounced overall effects on skin elastic or biological properties, but significant R6 (Uv/Ue) values indicate that it does have definite effects on the viscoelastic properties of the skin.
(n° 22) A review of phytotherapy of acne vulgaris: Perspective of new pharmacological treatments.
Azimi H, Fallah-Tafti M, Khakshur AA, Abdollahi M., Fitoterapia. 2012 Apr 10.
This review focuses on plants currently used and those with a high potency for the future development of anti-acne products. Anti-bacterial, anti-inflammatory, anti-oxidant, and anti-androgen effects were the key outcomes. Studies on cell lines revealed that flavonoid, alkaloid, essential oil, phenol and phenolic compound, tannin, xanthone and xanthone derivative, and the bisnaphthquione derivative are effective in treatment of acne. Animal studies showed that diterpene acid, phenylpropanoid glycosides, acteoside and flavonoids have anti-inflammatory activity. Eleven human studies revealed that Camellia Sinensis has 5α-reductase inhibitory and anti-inflammatory activities. Also anti-bacterial effect was shown by oleoresin of Commiphora mukul. In addition to the standardization of these herbs, screening herbs as anti-acne agents may help to find new sources of therapy for acne.
(n° 23) Exposure to specific herbal products during pregnancy and the risk of low birth weight.
Moussally K, Berard A., Altern Ther Health Med. 2012 Mar-Apr;18(2):36-43., Ste-Justine Research Center, Montreal.
Despite the fact that herbal products (HP) are used frequently during gestation worldwide, studies indicate that they may not be free of danger for fetuses. Evidence about the safety of HP use during pregnancy and their impact on pregnancy outcomes is currently lacking. To quantify the association between HP use during the last 2 trimesters of pregnancy (≥15 weeks of gestation [WG]) and more specifically, between use of chamomile (Anthemis nobilis), flax (Linum usitatissimum), peppermint (M. balsamea), or green tea (Camellia Sinensis) (alone or in combination with other HPs) and the risk of low birth weight (LBW). Cases were defined as women who delivered a newborn <2500g and controls as women who delivered a newborn ≥2500g. After adjusting for potential confounders, no statistically significant associations were found between the use of any HP during the last 2 trimesters of pregnancy and the risk of LBW, or between the use of flax, chamomile, peppermint, or green tea (alone or in combination with other HPs) during the last 2 trimesters of pregnancy and the risk of LBW. HP use during the last 2 trimesters of pregnancy and more specifically, use of flax, chamomile, peppermint, or green tea alone or in combination with other HPs did not significantly increase the risk of LBW.
(n° 24) The effects of green tea polyphenols on drug metabolism.
Yang CS, Pan E., Expert Opin Drug Metab Toxicol. 2012 Jun;8(6):677-89. Epub 2012 Apr 18., The State University of New Jersey, Piscataway, USA.
Tea, made from the dried leaves of the plant Camellia Sinensis Theaceae, is a very popular beverage consumed worldwide. Recently, green tea extract-based dietary supplements have also been widely consumed for the acclaimed beneficial health effects, such as weight reduction. Although tea consumption is considered to be innocuous, the potential interactions between tea polyphenols and drugs have been demonstrated in studies in vitro and in vivo. Tea catechins may bind to certain drugs to affect their absorption and bioactivities. Tea catechins may inhibit the activities of drug-metabolizing enzymes and drug transporters or affect the expression of these proteins, either upregulation or downregulation. Although these effects have been demonstrated in studies in vitro and in animal models, such effects have only been observed in limited cases in humans at common doses of human tea consumption. The ingestion of tea catechins from dietary supplements, which could be in large bullet doses, may produce more profound effects on drug metabolism, and such effects with drugs need to be further investigated.
(n° 25) Evaluation of the antiviral activity of a green tea solution as a hand-wash disinfectant.
Shin WJ, Kim YK, Lee KH, Seong BL., Biosci Biotechnol Biochem. 2012;76(3):581-4, Yonsei University, Seoul, South Korea.
Based on the broad-spectrum antiviral effect of green tea catechins, we established an experimental skin contact model for influenza virus transmission and evaluated the use of a green tea solution as a first-hand disinfectant. The infectivity of the virus on the skin cell layer became obsolete when washed with the green tea solution. The skin contact model could be applied to develop non-pharmaceutical intervention measures for reducing human transmission of the influenza virus.
(n° 26) Effects of Ilex latifolia and Camellia Sinensis on Cholesterol and Circulating Immune Complexes in Rats Fed with a High-Cholesterol Diet.
Luo XY, Li NN, Liang YR., Phytother Res. 2012 Mar 26. doi: 10.1002/ptr.4693., Zhejiang University, Hangzhou, PR China
Hypercholesterolaemia is one of the risk factors for atherosclerosis and subsequent cardiovascular disease. Here, we investigated the effects of dietary supplementation with Ilex latifolia or green tea (Camellia Sinensis) on the levels of plasma total cholesterol, high-density lipoprotein cholesterol and circulating immune complexes in Sprague Dawley rats fed with a high-cholesterol diet. We demonstrated that daily administration by gavage of I. latifolia or C. Sinensis at doses of 1.0 or 2.0 g/kg body weight for 30 days resulted in a significant decrease in plasma total cholesterol levels and circulating immune complexes and an increase in high-density lipoprotein cholesterol in rats fed with a high-cholesterol diet compared with levels in the high-cholesterol diet control group. C. Sinensis was more effective than I. latifolia. I. latifolia and C. Sinensis could be used as food supplements to protect against the development of hypercholesterolaemia.
(n° 27) Health-promoting effects of green tea.
Suzuki Y, Miyoshi N, Isemura M., Proc Jpn Acad Ser B Phys Biol Sci. 2012;88(3):88-101, Nagoya Keizai University, Inuyama, Japan.
Green tea is manufactured from the leaves of the plant Camellia Sinensis Theaceae and has been regarded to possess anti-cancer, anti-obesity, anti-atherosclerotic, anti-diabetic, anti-bacterial, and anti-viral effects. Many of the beneficial effects of green tea are related to the activities of (-)-epigallocatechin gallate (EGCG), a major component of green tea catechins. For about 20 years, we have engaged in studies to reveal the biological activities and action mechanisms of green tea and EGCG. This review summarizes several lines of evidence to indicate the health-promoting properties of green tea mainly based on our own experimental findings.
(n° 28) L-Theanine extends lifespan of adult Caenorhabditis elegans.
Zarse K, Jabin S, Ristow M., Eur J Nutr. 2012 Sep;51(6):765-8. Epub 2012 Mar 16., University of Jena, Jena, Germany.
Compounds that delay aging in model organisms may be of significant interest to anti-aging medicine, since these substances potentially provide pharmaceutical approaches to promote healthy lifespan in humans. We here aimed to test whether pharmaceutical concentrations of L: -theanine, a putative anti-cancer, anti-obesity, blood pressure-lowering, and neuroprotective compound contained in green tea (Camellia Sinensis), are capable of extending lifespan in a nematodal model organism for aging processes, the roundworm Caenorhabditis elegans. Adult C. elegans roundworms were maintained on agar plates, were fed E. coli strain OP50 bacteria, and L: -theanine was applied to agar to test (1) whether it may increase survival upon paraquat exposure and (2) whether it may promote longevity by quantifying survival in the presence and absence of the compound. L: -theanine increases survival of C. elegans in the presence of paraquat at a concentration of 1 micromolar. L: -theanine extends C. elegans lifespan when applied at concentrations of 100 nM, as well as 1 and 10 micromolar. In the model organism C. elegans, L: -theanine is capable of promoting paraquat resistance and longevity suggesting that this compound may as well promote healthy lifespan in mammals and possibly humans.
(n° 29) Inhibition of acetylcholinesterase by green and white tea and their simulated intestinal metabolites.
Okello EJ, Leylabi R, McDougall GJ., Food Funct. 2012 Mar 14, Newcastle University, Newcastle upon Tyne, United Kingdom.
By 2034 it is forecast that 5% of the global population will be aged 85 years or over-approximately two and half fold increase on present day figures-which will inevitably lead to an increase in age-associated disorders such as Alzheimer's disease. There is mounting evidence that green tea (Camellia Sinensis) possesses numerous health-promoting properties, and may potentially be beneficial to those suffering from Alzheimer's and other diseases, including cardiovascular disease and cancer. These beneficial properties are largely attributed to the high polyphenol content, particularly the catechins. Overall, the results indicate that further research is necessary to determine the full potential of digestion of tea and its metabolites and how inter-individual variation may indicate that some sections of society could potentially benefit more from drinking tea as a strategy to prevent the development of dementia. We have also shown the activities of a number of metabolites, however, further research is required to determine their potential bioavailability.
(n° 30) Evaluation of green tea extract as a glazing material for shrimp frozen by cryogenic freezing.
Sundararajan S, Prudente A, Bankston JD, King JM, Wilson P, Sathivel S., J Food Sci. 2011 Sep;76(7):E511-8. doi: 10.1111/j.1750-3841.2011.02283.x., Louisiana State Univ Agricultural Center, Baton Rouge, USA.
Solutions of green tea (Camellia Sinensis) extract (GTE) in distilled water were evaluated as a glazing material for shrimp frozen by cryogenic freezing. The HPLC analysis of GTE revealed the presence of catechins and their isomers and the total polyphenol content was 148.10 ± 2.49 g/L. The freezing time (min) and energy removal rate (J/s) were 48.67 ± 2.3 and 836.67 ± 78.95, respectively. Glazed samples had higher moisture content compared to NG shrimp after 180 d storage. GTE was effective in controlling the lipid oxidation in shrimp. Glazing with GTE affected a* and b* color values, but had no significant effect on the L* values of shrimp.
(n° 31) Evaluation of antitumour activity of tea carbohydrate polymers in hepatocellular carcinoma animals.
(n° 31) Evaluation of antitumour activity of tea carbohydrate polymers in hepatocellular carcinoma animals.
Chen B, Zhou W, Ning M, Wang Z, Zou L, Zhang H, Wang Q., Int J Biol Macromol. 2012 May 1;50(4):1103-8. Epub 2012 Mar 8., Department of Hepatobiliary Surgery of the General Hosptal of NingXia Medical University, Ningxia, PR China.
Box-Behnken design criterion was applied to identify the significant effects of various extraction parameters such as temperature, time, and solvent-solid ratio on extraction of tea carbohydrate. Among the three variables tested extraction temperature, and solvent-solid ratio were found to have significant effect on tea carbohydrate extraction. The most suitable condition for extraction of tea carbohydrate was found to be a single step extraction at extraction temperature 90°C, extraction time 30 min, and solvent-solid ratio 5:1. Hepatocellular carcinoma was induced by the injection of 1×10(5) H22 hepatocarcinoma cells into right hind thigh muscle in experimental animals. Tea carbohydrate could inhibit tumour growth and decrease microvessel density in tumour tissue. The altered amount of serum white blood cells (WBC), Interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) in HCC animals were dose-dependently increased, whereas activities of serum alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) were dose-dependently decreased in the drug treated animals. In addition, tea carbohydrate administration could decrease expression of vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) in H22 tumor tissue. It can be concluded that tea carbohydrate displayed strong antitumour activity in animals.
(n° 32) Tea catechins and flavonoids from the leaves of Camellia Sinensis inhibit yeast alcohol dehydrogenase.
Manir MM, Kim JK, Lee BG, Moon SS., Bioorg Med Chem. 2012 Apr 1;20(7):2376-81. Epub 2012 Feb 9, Kongju National University, Gongju, Republic of Korea.
Four new quercetin acylglycosides, designated camelliquercetisides A-D, quercetin 3-O-[α-L-arabinopyranosyl(1→3)][2-O″-(E)-p-coumaroyl][β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→6)]-β-D-glucoside (17), quercetin 3-O-[2-O″-(E)-p-coumaroyl][β-D-glucopyranosyl(1→3)-α-L-rhamnopyranosyl(1→6)]-β-D-glucoside (18), quercetin 3-O-[α-L-arabinopyranosyl(1→3)][2-O″-(E)-p-coumaroyl][α-L-rhamnopyranosyl(1→6)]-β-d-glucoside (19), and quercetin 3-O-[2-O″-(E)-p-coumaroyl][α-L-rhamnopyranosyl(1→6)]-β-D-glucoside (20), together with caffeine and known catechins, and flavonoids (1-16) were isolated from the leaves of Camellia Sinensis. Their structures were determined by spectroscopic (1D and 2D NMR, IR, and HR-TOF-MS) and chemical methods. The catechins and flavonoidal glycosides exhibited yeast alcohol dehydrogenase (ADH) inhibitory activities in the range of IC(50) 8.0-70.3μM, and radical scavenging activities in the range of IC(50) 1.5-43.8 μM, measured by using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical.
(n° 33) Epicatechin-3-O-(3″-O-methyl)-gallate content in various tea cultivars (Camellia Sinensis L.) and its in vitro inhibitory effect on histamine release.
Maeda-Yamamoto M, Ema K, Monobe M, Tokuda Y, Tachibana H., J Agric Food Chem. 2012 Mar 7;60(9):2165-70. Epub 2012 Feb 27, National Institute of Vegetable and Tea Science, Kanaya, Shizuoka, Japan.
It has been reported that epigallocatechin-3-O-(3″-O-methyl)-gallate (EGCG3″Me) and the EGCG3″Me-rich green tea ( Camellia Sinensis L.) cultivar 'Benifuuki' exhibit antiallergic effects. At a dose of 50 μg/mL, the rank order of histamine release inhibition was observed to be epicatechin-3-O-(3″-O-methyl)-gallate (ECG3″Me) > gallocatechin-3-O-(3″-O-methyl)-gallate (GCG3″Me) > EGCG3″Me > gallocatechin-gallate (GCG) > catechin-gallate (CG) > EGCG > epicatechin-gallate (ECG) > epigallocatechin (EGC) > gallocatechin (GC). Of the various tea cultivars analyzed by HPLC, the greatest content of ECG3″Me was found in the third crop of 'Benifuuki' (1.05% dry weight). Moreover, ECG3″Me content was positively correlated with EGCG3″Me content in 'Benifuuki' tea leaves. In an assay of mixtures of ECG3″Me and EGCG3″Me, inhibitory activity (50 μg/mL in total) was increased as the content of ECG3″Me increased. This suggests that ECG3″Me might link to the antiallergic effect of 'Benifuuki' tea, as has been reported for EGCG3″Me.
(n° 34) Effect of green tea extract on body weight, serum glucose and lipid profile in streptozotocin-induced diabetic rats. A dose response study.
Haidari F, Shahi MM, Zarei M, Rafiei H, Omidian K., Saudi Med J. 2012 Feb;33(2):128-33., Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
To examine the effect of green tea extract on body weight, serum levels of glucose, and lipids in streptozotocin-induced diabetic rats. Administration of green tea extract caused a significant decrease in serum glucose and total cholesterol levels and significantly improved the body weight loss in diabetic rats treated with 200 mg/kg green tea in comparison to diabetic control group. No significant changes were observed in triglyceride (p=0.04), low-density-lipoprotein cholesterol (p=0.000), and high-density-lipoprotein cholesterol levels (p=0.01) following intervention. It appears that green tea extract had both antihyperglycemic and hypocholesterolmic effects in diabetic rats, although further work is needed to determine their mechanism.
(n° 35) Green tea extract alleviates arsenic-induced biochemical toxicity and lipid peroxidation in rats.
Messarah M, Saoudi M, Boumendjel A, Kadeche L, Boulakoud MS, El Feki A., Toxicol Ind Health. 2012 Feb 2., Badji Mokhtar University, Algeria.
The present work was undertaken to evaluate the protective effect of an aqueous extract of green tea (GT, Camellia Sinensis) leaves against arsenic (NaAsO(2))-induced biochemical toxicity and lipid peroxidation production in experimental rats. The treatment with arsenic exhibited a significant increase in some serum hepatic and renal biochemical parameters (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, total protein, albumin, bilirubin, cholesterol, urea and creatinine). To conclude, our data suggest that arsenic exposure enhanced an oxidative stress by disturbing the tissue antioxidant defense system, but the GT co-administration alleviates the toxicity induced by arsenic exposure.
(n° 36) Effects of (-)-Epigallocatechin Gallate on the Motility and Penetrability of Frozen-Thawed Boar Spermatozoa Incubated in the Fertilization Medium.
Kaedei Y, Naito M, Naoi H, Sato Y, Taniguchi M, Tanihara F, Kikuchi K, Nagai T, Otoi T., Reprod Domest Anim. 2012 Feb 2. doi: 10.1111/j.1439-0531.2012.01984.x. , The United Graduate School of Veterinary Science, Yamaguchi University, Ibaraki, Japan.
Epigallocatechin gallate (EGCG) is the major polyphenol in green tea (Camellia Sinensis) and is known for its antioxidant effects. The objective of the present study was to examine the effects of EGCG during in vitro fertilization (IVF) on the sperm quality and penetrability into oocytes. Our results indicate that motility and penetrability of boar spermatozoa are improved by co-incubation with 50μm EGCG, but the effects vary with individual boars.
(n° 37) Isolation and identification of spermidine derivatives in tea (Camellia Sinensis) flowers and their distribution in floral organs.
Yang Z, Dong F, Baldermann S, Murata A, Tu Y, Asai T, Watanabe N., J Sci Food Agric. 2012 Aug 15;92(10):2128-32. doi: 10.1002/jsfa.5596. Epub 2012 Feb 1, Shizuoka University, Ohya, Suruga-ku, Shizuoka, Japan.
Recently, tea (Camellia Sinensis) flowers have attracted increasing interest because of their content of bioactive compounds such as catechins. The aim of this study was to investigate the occurrence of some characteristic compounds in tea flowers. This study has provided the first evidence that spermidine-phenolic acid conjugates occur in tea flowers in considerable amounts. Their presence should prompt a reconsideration of the ecological role of tea flowers. From an economic point of view, tea flowers might be suitable as a raw material in the healthcare food and pharmaceutical industries.
(n° 38) Nutrition strategies to improve physical capabilities in Duchenne muscular dystrophy.
Davoodi J, Markert CD, Voelker KA, Hutson SM, Grange RW., Phys Med Rehabil Clin N Am. 2012 Feb;23(1):187-99, xii-xiii. Epub 2011 Dec 13, Virginia Tech, Blacksburg, USA.
There is no current cure for Duchenne muscular dystrophy (DMD), and palliative and prophylactic interventions to improve the quality of life of patients remain limited, with the exception of corticosteroids. This article describes 2 potential nutritional interventions for the treatment of DMD, green tea extract (GTE) and the branched-chain amino acid leucine, and their positive effects on physical activity. Both GTE and leucine are suitable for human consumption, are easily tolerated with no side effects, and, with appropriate preclinical data, could be brought forward to clinical trials rapidly.
(n° 39) Caffeinated beverage intake and reproductive hormones among premenopausal women in the BioCycle Study.
Schliep KC, Schisterman EF, Mumford SL, Pollack AZ, Zhang C, Ye A, Stanford JB, Hammoud AO, Porucznik CA, Wactawski-Wende J., Am J Clin Nutr. 2012 Feb;95(2):488-97. Epub 2012 Jan 11., Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, USA.
Caffeinated beverages are widely consumed among women of reproductive age, but their association with reproductive hormones, and whether race modifies any such associations, is not well understood. We assessed the relation between caffeine and caffeinated beverage intake and reproductive hormones in healthy premenopausal women and evaluated the potential effect modification by race. Moderate consumption of caffeine was associated with reduced estradiol concentrations among white women, whereas caffeinated soda and green tea intakes were associated with increased estradiol concentrations among all races. Further research is warranted on the association between caffeine and caffeinated beverages and reproductive hormones and whether these relations differ by race.
(n° 40) Potential role of green tea catechins in various disease therapies: progress and promise.
Mak JC., Clin Exp Pharmacol Physiol. 2012 Mar;39(3):265-73. doi: 10.1111/j.1440-1681.2012.05673.x, The University of Hong Kong, Hong Kong, China.
Green tea (from the plant Camellia Sinensis), a beverage whose consumption started 5000 years ago in China, has important biological and pharmacological properties. The beneficial effects of green tea have been attributed to the presence of phenolic compounds that are powerful anti-oxidants and free iron scavengers. Of all the catechins found in green tea, namely (-)-epicatechin-3-gallate, (-)-epigallocatechin, (-)-epicatechin and (-)-epigallocatechin-3-gallate (EGCG), EGCG is the most abundant and powerful. It is widely believed that green tea may protect against death from all causes, especially cardiovascular diseases (coronary heart disease and stroke) owing to the presence of catechins associated with green tea consumption. Other health benefits include various types of cancer chemoprevention, weight loss and protective effects against neurodegenerative diseases (Alzheimer's disease and Parkinson's disease). Although most of the studies have shown benefits with two to three cups of green tea per day, the optimal dose has not yet been established to enable any solid conclusions to be drawn regarding the various health benefits of green tea or its constituents in humans. With Phase I trials providing information on the safety profile and pharmacokinetics of EGCG, the window of opportunity is wider to undertake well-controlled long-term human studies to enable a full understanding of the protective effects of green tea catechins on various parameters in different settings.
(n° 41) The Effects of Rooibos (Aspalathus linearis), Green Tea (Camellia Sinensis) and Commercial Rooibos and Green Tea Supplements on Epididymal Sperm in Oxidative Stress-induced Rats.
Awoniyi DO, Aboua YG, Marnewick J, Brooks N., Phytother Res. 2012 Aug;26(8):1231-9. doi: 10.1002/ptr.3717. Epub 2012 Jan 7, Cape Peninsula University of Technology, Bellville, South Africa.
Reactive oxygen species (ROS) are involved in many physiological functions of mammalian sperm. Numerous endogenous antioxidants belonging to both enzymatic and non-enzymatic groups can remove excess ROS and prevent oxidative stress (OS). This study compares the modulation of OS by rooibos, Chinese green tea and commercial rooibos and green tea supplements in rat sperm. Catalase activity was significantly higher in the sperm of rats consuming fermented rooibos, 'green' rooibos and both the rooibos and green tea supplements. Superoxide dismutase concentration in the sperm of rats supplemented with fermented rooibos, 'green' rooibos and green tea was higher. Sperm glutathione levels of rats consuming the fermented and 'green' rooibos were also significantly higher. Rooibos fermented and 'green' rooibos showed a tendency to lower the levels of ROS and lipid peroxidation when compared with the control group. In conclusion, both rooibos extracts could offer a measure of protection against induced oxidative damage by increasing the antioxidant defence mechanisms and thereby improving the sperm quality and function.
(n° 42) Cardiovascular effects of black tea and nicotine alone or in combination against experimental induced heart injury.
Joukar S, Bashiri H, Dabiri S, Ghotbi P, Sarveazad A, Divsalar K, Joukar F, Abbaszadeh M., J Physiol Biochem. 2012 Jun;68(2):271-9. Epub 2012 Jan 7., Kerman University of Medical Sciences, Kerman, Iran.
The present study was designed to elucidate the outcome of subchronic co-administration of black tea and nicotine on cardiovascular performance and whether these substances could modulate the isoproterenol-induced cardiac injury. When the cardiac injury was induced, tea consumption maintained the maximum dp/dt, and nicotine significantly decreased the pressure-rate product. Moreover, severity of heart lesions was lower in the presence of nicotine or black tea. Concomitant use of these materials did not show extra effects on mentioned parameters more than the effect of each of them alone. The results suggest that subchronic administration of black tea or nicotine for a period of 4 weeks may have a mild cardioprotective effect, while concomitant use of these materials cannot intensify this beneficial effect.
(n° 43) Black tea (Camellia Sinensis) decoction shows immunomodulatory properties on an experimental animal model and in human peripheral mononuclear cells.
Chattopadhyay C, Chakrabarti N, Chatterjee M, Mukherjee S, Sarkar K, Chaudhuri AR., Pharmacognosy Res. 2012 Jan;4(1):15-21, KPC Medical College and Hospital, Kolkata, West Bengal, India.
Black tea (Camellia Sinensis) has been used as a daily beverage for time immemorial. Immunomodulatory effects of tea are recognized as it stimulates the proliferation of cultured human peripheral blood mononuclear cells. Anti-inflammatory effects of tea have also been depicted in the available literature. Therefore, we designed this study to examine the potential immunemodulatory and anti-inflammatory activities of black tea in a rat model and in human peripheral mononuclear cells. The purpose of the study was to determine (1) evaluation of anti-inflammatory effects of black tea on rats, (2) evaluation of immunemodulator effects of black tea on rats, and (3) evaluation of immunemodulator effects of black tea on human peripheral mononuclear cells. Black tea decoction (10% and 20%) strength has shown significant anti-inflammatory effects (64.8% and 77% reduction, respectively), on carrageenan-induced acute inflammatory models (rat paw edema) which can be comparable with the standard drug indomethacin (89.1%). In a chronic anti-inflammatory model, black tea decoction (10% and 20%) has shown significant suppressive effects on rat paw edema (38.56% and 69.53%) observed on 21(st) day. Lymphoproliferative action of tea was evaluated on human peripheral mononuclear cells using an MTT assay where the number of living cells were expressed in terms of optical density at 570 nm. An experiment has shown that black tea increases the maximum number of T-lymphocytes at 72 h with a maximum strength of 20%. Maximum number of viable cells (T-lymphocytes) was observed with black tea at 20% strength at 72 h. The results were expressed as mean ± SD, and the significance was evaluated by Student's t-test versus control, with P < 0.05 implying significance. Taken together, our data indicate that black tea has potential anti-inflammatory and immunomodulatory action and this corroborates with the current trend of tea being promoted as a 'health drink'.
(n° 44) Antioxidant and antibacterial properties of green, black, and herbal teas of Camellia Sinensis.
Chan EW, Soh EY, Tie PP, Law YP., Pharmacognosy Res. 2011 Oct;3(4):266-72., UCSI University, Cheras, Kuala Lumpur, Malaysia.
The role of non-polymeric phenolic (NP) and polymeric tannin (PT) constituents in the antioxidant and antibacterial properties of six brands of green, black, and herbal teas of Camellia Sinensis were investigated. Extraction yields ranged from 12 to 23%. Yields of NP fractions (70-81%) were much higher than those of PT fractions (1-11%), suggesting that the former are the major tea components. Ranking of antioxidant properties of extracts was green tea>black tea>herbal tea. For all six teas, antioxidant properties of PT fractions were significantly higher than extracts and NP fractions. Extracts and fractions of all six teas showed no activity against the three Gram-negative bacteria. Green teas inhibited all three Gram-positive bacteria with S. aureus being the least susceptible. Black and herbal teas inhibited the growth of M. luteus and B. cereus, but not S. aureus. The most potent were the PT fractions of Boh Cameron Highlands and Ho Yan Hor with MID of 0.01 and 0.03 mg/disc against M. luteus. Results suggested that NP constituents are major contributors to the antioxidant and antibacterial properties of teas of C. Sinensis. Although PT constituents have stronger antioxidant and antibacterial properties, they constitute only a minor component of the teas.
(n° 45) Preventive effects of green tea (Camellia Sinensis var. assamica) on diabetic nephropathy.
Kang MY, Park YH, Kim BS, Seo SY, Jeong BC, Kim JI, Kim HH., Yonsei Med J. 2012 Jan;53(1):138-44. doi: 10.3349/ymj.2012.53.1.138, Seoul National University College of Medicine and Clinical Research Institute, Seoul, Korea.
This study aimed to evaluate the preventive effects of Camellia Sinensis var. assamica (CSVA) on diabetic nephropathy in in vitro and in vivo models. MDCK cells were incubated with 1 mM of oxalate with or without different concentrations of CSVA, then MTT and malondialdehyde (MDA) assays were performed to investigate the preventive effects of CSVA on oxalate-induced cytotoxicity and oxidative stress. As CSVA concentrations increased, viable MDCK cells increased in concentration. MDA production decreased over time in the CSVA treated group. The creatinine clearance of group 3 was lower than those of groups 1 and 2. The amount of urine microalbumin and protein in group 1 were higher than those in groups 2 and 3. Also, more glomerulus basement membrane foot processes were preserved in groups 2 and 3. In conclusion, CSVA has beneficial preventive tendencies towards diabetic nephropathy in both in vitro and in vivo models.
(n° 46) Tea polyphenols inhibit rat osteoclast formation and differentiation.
Oka Y, Iwai S, Amano H, Irie Y, Yatomi K, Ryu K, Yamada S, Inagaki K, Oguchi K., J Pharmacol Sci. 2012;118(1):55-64. Epub 2011 Dec 21, Showa University School of Medicine, Japan.
Matrix metalloproteinases (MMPs) play an important role in degeneration of the matrix associated with bone and cartilage. Regulation of osteoclast activity is essential in the treatment of bone disease, including osteoporosis and rheumatoid arthritis. Polyphenols in green tea, particularly epigallocatechin-3-gallate (EGCG), inhibit MMPs expression and activity. However, the effects of the black tea polyphenol, theaflavin-3,3'-digallate (TFDG), on osteoclast and MMP activity are unknown. Therefore, we examined whether TFDG and EGCG affect MMP activity and osteoclast formation and differentiation in vitro. TFDG or EGCG (10 and 100 µM) was added to cultures of rat osteoclast precursors cells and mature osteoclasts. Numbers of multinucleated osteoclasts and actin rings decreased in polyphenol-treated cultures relative to control cultures. MMP-2 and MMP-9 activities were lower in TFDG- and EGCG-treated rat osteoclast precursor cells than in control cultures. MMP-9 mRNA levels declined significantly in TFDG-treated osteoclasts in comparison to control osteoclasts. TFDG and EGCG inhibited the formation and differentiation of osteoclasts via inhibition of MMPs. TFDG may suppress actin ring formation more effectively than EGCG. Thus, TFDG and EGCG may be suitable agents or lead compounds for the treatment of bone resorption diseases.
(n° 47) Anti-influenza virus activity of green tea by-products in vitro and efficacy against influenza virus infection in chickens.
Lee HJ, Lee YN, Youn HN, Lee DH, Kwak JH, Seong BL, Lee JB, Park SY, Choi IS, Song CS., Poult Sci. 2012 Jan;91(1):66-73, Konkuk University, Seoul, Korea.
Polyphenolic compounds present in green tea, particularly catechins, are known to have strong anti-influenza activity. The goal of this study was to determine whether green tea by-products could function as an alternative to common antivirals in animals compared to original green tea. The anti-influenza activity of green tea by-products was further examined in mouse and chicken influenza infection models. In mice, oral administration of green tea by-products reduced viral titers in the lungs in the early phase of infection, but they could not protect these animals from disease and death. In contrast, therapeutic administration of green tea by-products via feed or water supplement resulted in a dose-dependent significant antiviral effect in chickens, with a dose of 10 g/kg of feed being the most effective (P < 0.001). We also demonstrated that unidentified hexane-soluble fractions of green tea by-products possessed strong anti-influenza activity, in addition to ethyl acetate-soluble fractions, including catechins. This study revealed green tea by-product extracts to be a promising novel antiviral resource for animals.
(n° 48) Fatty Acid Composition and Antioxidant Activity of Tea (Camellia Sinensis L.) Seed Oil Extracted by Optimized Supercritical Carbon Dioxide.
Wang Y, Sun D, Chen H, Qian L, Xu P., Int J Mol Sci. 2011;12(11):7708-19. Epub 2011 Nov 8, Zhejiang University, Hangzhou, China
Seeds are another product in addition to leaves (raw materials for teas) of tea (Camellia Sinensis L.) plant. The great increase of tea consumption in recent years raises the challenge of finding commercial applications for tea seeds. In the present study, supercritical carbon dioxide (SC-CO(2)) extraction edible oil from tea seed was carried out, response surface methodology (RSM) was used to optimize processing parameters including time (20-90 min), temperature (35-45 °C) and pressure (50-90 MPa). The fatty acid composition and antioxidant activity of the extracted oil was also investigated. The highest yield of oil (29.2 ± 0.6%) was obtained under optimal SC-CO(2) extraction conditions (45 °C, 89.7 min and 32 MPa, respectively), which was significantly higher (p < 0.05) than that (25.3 ± 1.0%) given by Soxhlet extraction. Meanwhile, tea seed oil extracted by SC-CO(2) contained approximately 80% unsaturated fatty acids and showed a much stronger scavenging ability on the DPPH radical than that extracted by Soxhlet. SC-CO(2) is a promising alternative for efficient extraction of edible oil from tea seed. Moreover, tea seed oil extracted by SC-CO(2) is highly edible and has good antioxidant activity, and therefore may play a potential role as a health-promoting food resource in human diets.
(n° 49) Synergistic antioxidant activity of green tea with some herbs.
Jain DP, Pancholi SS, Patel R., J Adv Pharm Technol Res. 2011 Jul;2(3):177-83, NMT Gujarati College of Pharmacy, Indore, Madhya Pradesh, India.
Cardiovascular diseases, cancer, arthritis, etc. are caused by free radicals that are byproducts of metabolic pathways. Selected plants namely Vitis vinifera, Phyllanthus emblica L., Punica granatum, Cinnamomum cassia, Ginkgo biloba L., and Camellia Sinensis Linn. are reported to produce antioxidant property. This study is undertaken to support the hypothesis that formulation of a polyherbal combination of these plants shows a synergistic effect with green tea. The extracts of each drug were characterized by phytochemical studies and tests for phenolics and flavonoids. In vitro antioxidant activity for individual drug and its combination was determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH), superoxide, and nitric oxide free radical scavenging methods. Our results suggest that a combination of all these herbs with green tea can synergistically enhance antioxidant activity and thus lower doses of each herb with green tea may be used. Antioxidant potential of polyherbal combination was also comparable to that of standard ascorbic acid. Studies showed that selected individual plants contained abundant quantity of phenolics and flavonoids and their polyherbal combination with green tea was found to produce best antioxidant activity among all individual extracts. This will help in avoiding undesirable side effects due to higher doses of single herb.
(n° 50) Green tea protects human osteoblasts from cigarette smoke-induced injury: possible clinical implication.
Holzer N, Braun KF, Ehnert S, Egaña JT, Schenck TL, Buchholz A, Schyschka L, Neumaier M, Benzing S, Stöckle U, Freude T, Nussler AK., Langenbecks Arch Surg. 2012 Mar;397(3):467-74. Epub 2011 Dec 8., Technische Universität München, Munich, Germany.
Recent reports discuss the altered bone homeostasis in cigarette smokers, being a risk factor for osteoporosis and negatively influencing fracture healing. Cigarette smoke is known to induce oxidative stress in the body via an increased production of reactive oxygen species (ROS). These increases in ROS are thought to damage the bone-forming osteoblasts. Naturally occurring polyphenols contained in green tea extract (GTE), e.g., catechins, are known to have anti-oxidative properties. Our data suggest possible beneficial effects on bone homeostasis, fracture healing, and bone mineral density following a GTE-rich diet or supplementation.
(n° 51) Updated bioavailability and 48 h excretion profile of flavan-3-ols from green tea in humans.
Calani L, Del Rio D, Luisa Callegari M, Morelli L, Brighenti F., Int J Food Sci Nutr. 2012 Aug;63(5):513-21. Epub 2011 Dec 2, University of Parma , Parma , Italy.
Green tea is a popular beverage, prepared with infusion of unfermented dried leaves of Camellia Sinensis, and is one of the most relevant sources of polyphenolic compounds in the human diet. This study reports green tea flavan-3-ol absorption, metabolism and complete urinary excretion up to 48 h in 20 healthy volunteers. Green tea contained monomeric flavan-3-ols and proanthocyanidins with a total polyphenol content of 728 μmol. A total of 41 metabolites were identified in urines, all present in conjugated forms. Among these, six colonic metabolites of green tea flavan-3-ols were identified for the first time after green tea consumption in humans. The average 48 h bioavailability was close to 62%, major contributors being microbial metabolites. Some volunteer showed a 100% absorption/excretion, whereas some others were unable to efficiently absorb/excrete this class of flavonoids. This suggests that colonic ring fission metabolism could be relevant in the putative bioactivity of green tea polyphenols.
(n° 52) Acute neurocognitive effects of epigallocatechin gallate (EGCG).
Scholey A, Downey LA, Ciorciari J, Pipingas A, Nolidin K, Finn M, Wines M, Catchlove S, Terrens A, Barlow E, Gordon L, Stough C., Appetite. 2012 Apr;58(2):767-70. Epub 2011 Nov 20., Swinburne University, Melbourne, Australia.
Green tea is reported to have wide ranging beneficial health outcomes across epidemiological studies, which have been attributed to its flavonoid content. We investigated whether the flavonoid epigallocatechin gallate (EGCG) modulates brain activity and self-reported mood in a double-blind, placebo controlled crossover study. Participants completed baseline assessments of cognitive and cardiovascular functioning, mood and a resting state electroencephalogram (EEG) before and then 120 min following administration of 300 mg EGCG or matched placebo. EGCG administration was associated with a significant overall increase in alpha, beta and theta activity, also reflected in overall EEG activity, more dominant in midline frontal and central regions, specifically in the frontal gyrus and medial frontal gyrus. In comparison to placebo the EGCG treatment also increased self-rated calmness and reduced self rated stress. This pattern of results suggests that participants in the EGCG condition may have been in a more relaxed and attentive state after consuming EGCG. This is in keeping with the widespread consumption of green tea for its purported relaxing/refreshing properties. The modulation of brain function due to EGCG is deserving of further controlled human studies.
(n° 53) A crude extract from immature green tea (Camellia Sinensis) leaves promotes Toll-like receptor 7-mediated interferon-α production in human macrophage-like cells.
Monobe M, Ogino A, Ema K, Tokuda Y, Maeda-Yamamoto M., Cytotechnology. 2012 Mar;64(2):145-8. Epub 2011 Nov 29, NARO Institute of Vegetable and Tea Science, Kanaya-Shishidoi, Shimada, Shizuoka, Japan
Toll-like receptor 7 (TLR7) senses viral single-stranded RNA (ssRNA), induces the production of type I interferons (IFNs), IFN-α and -β, in macrophages such as dendritic cells (DCs), and its immune system protects the host from virus infection. Here, we found that a crude extract from immature green tea leaves (iTPS) containing a macromolecule with ssRNA fragments, induces IFN-α production in human macrophage-like cells. In addition IFN-α production was inhibited by treatment with TLR7 inhibitors or a phagocytosis inhibitor.
(n° 54) Dietary agents in the prevention of alcohol-induced hepatotoxicty: preclinical observations.
Shivashankara AR, Azmidah A, Haniadka R, Rai MP, Arora R, Baliga MS., Food Funct. 2012 Feb;3(2):101-9. Epub 2011 Nov 28, Father Muller Medical College, Kankanady, Mangalore, Karnataka, India.
Long term alcohol consumption is one of the important causes for liver failure and death. To complicate the existing problem there are no dependable hepatoprotective drugs and a large number of patients prefer using complementary and alternative medicines for treating and managing hepatic complications. Almost 25 centuries ago, Hippocrates, the father of medicine, proclaimed "Let food be thy medicine and medicine be thy food." Exploring the association between diet and health continues even today. Preclinical studies carried out in the recent past have shown that the commonly used dietary agents like Allium sativum (garlic), Camellia Sinensis (tea), Curcuma longa (turmeric), Emblica officinalis (Indian gooseberry), Ferula asafoetida (asafoetida), Garcinia cambogia (Malabar tamarind), Glycine max (soyabean), Murraya koenigii (curry leaves), Piper betle (beetle leaf), Prunus armeniaca (apricot), Ocimum gratissimum (wild basil), Theobroma cacao (cocoa), Trigonella foenum-graecum (fenugreek) and Vitis vinifera (grapes) protect against ethanol-induced hepatotoxicity. Mechanistic studies have shown that the beneficial effects of these phytochemicals in preventing the ethanol-induced hepatotoxicity are mediated by the antioxidant, free radical scavenging, anti-inflammatory and anti-fibrotic effects. The present review for the first time collates the hepatoprotective effects of these agents and also emphasizes on aspects that need future research to establish their utility in humans.
(n° 55) Green tea extract supplementation gives protection against exercise-induced oxidative damage in healthy men.
Jówko E, Sacharuk J, Balasińska B, Ostaszewski P, Charmas M, Charmas R., Nutr Res. 2011 Nov;31(11):813-21, Jozef Pilsudski University of Physical Education in Warsaw, Poland.
The purpose of this study was to evaluate the effects of a long-term (4-week) green tea extract (GTE) supplementation in combination with strength training on selected blood markers of oxidative stress and muscular damage after a short-term exercise in previously untrained men. We hypothesized that GTE supplementation would elevate antioxidant potential and attenuate exercise-induced oxidative stress and muscular damage. In conclusion, in previously untrained men, dietary supplementation with GTE (in combination with strength training) enhances the antioxidant defense system in plasma at rest and, in turn, may give protection against oxidative damage induced by both short-term muscular endurance test and long-term strength training.
(n° 56) Concomitant inhibition of HSP90, its mitochondrial localized homologue TRAP1 and HSP27 by green tea in pancreatic cancer HPAF-II cells.
Zhang L, Pang E, Loo RR, Rao J, Go VL, Loo JA, Lu QY., Proteomics. 2011 Dec;11(24):4638-47. doi: 10.1002/pmic.201100242. Epub 2011 Nov 23., University of California, Los Angeles, USA.
Pancreatic cancer is a deadly disease characterized by poor prognosis and patient survival. Green tea polyphenols have been shown to exhibit multiple antitumor activities in various cancers, but studies on the pancreatic cancer are very limited. To identify the cellular targets of green tea action, we exposed a green tea extract (GTE) to human pancreatic ductal adenocarcinoma HPAF-II cells and performed two-dimensional gel electrophoresis of the cell lysates. Our study has identified multiple new molecular targets of GTE and provided further evidence on the anticancer activity of green tea in pancreatic cancer.
(n° 57) Lipid rafts mediate epigallocatechin-3-gallate- and green tea extract-dependent viability of human colon adenocarcinoma COLO 205 cells; clusterin affects lipid rafts-associated signaling pathways.
Pajak B, Kania E, Gajkowska B, Orzechowski A., J Physiol Pharmacol. 2011 Aug;62(4):449-59, Polish Academy of Sciences, Warsaw, Poland.
Epigallocatechin-3-gallate (EGCG) is an important bioactive constituent of green tea extract (GTE) that was widely believed to reduce proliferation of many cancer cell lines. The purpose of this study was to verify the possible pro-apoptotic action of GTE/EGCG in human colon adenocarcinoma COLO 205 cells. The effect of EGCG/GTE treatments on cell viability was studied using methyl thiazolyl tetrazolium (MTT) assay. Our studies demonstrated that EGCG and GTE stimulate cell survival and proliferation of COLO 205 cells in a lipid rafts-dependent manner via at least MEK/ERK1/2 signaling pathway. Furthermore, EGCG/GTE mediated positive effects on viability and mitogenicity of COLO 205, while suppression of β-catenin activity was positively correlated with sClu clusterin expression.
(n° 58) The pharmacological mechanism of angiotensin-converting enzyme inhibition by green tea, Rooibos and enalaprilat - a study on enzyme kinetics.
Persson IA., Phytother Res. 2012 Apr;26(4):517-21. doi: 10.1002/ptr.3588. Epub 2011 Sep 8., Linköping University, Sweden.
Green tea (Camellia Sinensis L.) and Rooibos (Aspalathus linearis Dahlg.) inhibit angiotensin-converting enzyme (ACE) in vitro and in vivo. The ACE inhibitor enalaprilat has been described previously as a competitive inhibitor and sometimes as a non-competitive inhibitor. The aim of this study was to investigate the pharmacological mechanism of ACE inhibition of green tea and Rooibos by enzyme kinetics, and to compare this with enalaprilat. Incubating serum with green tea or Rooibos saturated with zinc chloride did not change the inhibitory effect. Enalaprilat preincubated with zinc chloride showed a decrease in the inhibitory effect. In conclusion, green tea, Rooibos and enalaprilat seem to inhibit ACE activity using a mixed inhibitor mechanism.
(n° 59) Black tea theaflavins inhibit formation of toxic amyloid-β and α-synuclein fibrils.
Grelle G, Otto A, Lorenz M, Frank RF, Wanker EE, Bieschke J., Biochemistry. 2011 Dec 13;50(49):10624-36. Epub 2011 Nov 16, Max Delbrück Centrum für Molekulare Medizin, Berlin-Buch, Germany.
Causal therapeutic approaches for amyloid diseases such as Alzheimer's and Parkinson's disease targeting toxic amyloid oligomers or fibrils are still emerging. Here, we show that theaflavins (TF1, TF2a, TF2b, and TF3), the main polyphenolic components found in fermented black tea, are potent inhibitors of amyloid-β (Aβ) and α-synuclein (αS) fibrillogenesis. Their mechanism of action was compared to that of two established inhibitors of amyloid formation, (-)-epigallocatechin gallate (EGCG) and congo red (CR). All three compounds reduce the fluorescence of the amyloid indicator dye thioflavin T. Like EGCG but unlike congo red, theaflavins stimulate the assembly of Aβ and αS into nontoxic, spherical aggregates that are incompetent in seeding amyloid formation and remodel Aβ fibrils into nontoxic aggregates. When compared to EGCG, TF3 was less susceptible to air oxidation and had an increased efficacy under oxidizing conditions. These findings suggest that theaflavins might be used to remove toxic amyloid deposits.
(n° 60) The effect of green tea polyphenols on macrophage migration inhibitory factor-associated steroid resistance.
Noh SU, Park YM., Br J Dermatol. 2012 Mar;166(3):653-7. doi: 10.1111/j.1365-2133.2011.10720.x., The Catholic University of Korea, Banpo-Dong, Seocho-Gu, Seoul, Korea.
Recently, evidence has been obtained to suggest that inflammation is provoked through upregulation of macrophage migration inhibitory factor (MIF) expression by steroids. However, little is known regarding the effect of steroids on MIF expression in human keratinocytes and the counter-effect of epigallocatechin-3-gallate (EGCG), a member of the class of green tea polyphenols. Dexamethasone significantly enhanced MIF expression in human keratinocytes, and EGCG significantly downregulated the expression of dexamethasone-induced MIF. EGCG also significantly downregulated rh-MIF-induced expression of Th-related cytokines and chemokines, such as interleukin (IL)-6, IL-18, transforming growth factor-β, CCL17, CCL22 and CXCL10, in human keratinocytes. These results demonstrated that EGCG may have a novel pharmacological effect to prevent steroid-induced tachyphylaxis and inflammation by suppressing the expression of MIF in human keratinocytes.
(n° 61) Preparation, preliminary characterization, antioxidant, hepatoprotective and antitumor activities of polysaccharides from the flower of tea plant (Camellia Sinensis).
Xu R, Ye H, Sun Y, Tu Y, Zeng X., Food Chem Toxicol. 2012 Jul;50(7):2473-80. Epub 2011 Oct 19, Nanjing Agricultural University, Nanjing, China.
In the present study, the crude polysaccharides from the flowers of tea plant (Camellia Sinensis) (TFPS) were prepared with hot water and further fractionated on a DEAE-52 cellulose chromatography to afford three purified fractions of TFPS-1, TFPS-2 and TFPS-3. Then, their preliminary structures, antioxidant and antitumor activities in vitro and hepatoprotective activity in vivo were investigated. The results suggested that TFPS should be a potent natural polymer with antioxidant, hepatoprotective and antitumor activities.
(n° 62) Black tea extract prevents lipopolysaccharide-induced NF-κB signaling and attenuates dextran sulfate sodium-induced experimental colitis.
Song YA, Park YL, Kim KY, Chung CY, Lee GH, Cho DH, Ki HS, Park KJ, Cho SB, Lee WS, Kim N, Ahn BW, Joo YE., BMC Complement Altern Med. 2011 Oct 11;11:91, Chonnam National University Medical School, Gwangju, Korea.
Black tea has been shown to elicit anti-oxidant, anti-carcinogenic, anti-inflammatory and anti-mutagenic properties. In this study, we investigated the impact of black tea extract (BTE) on lipopolysaccharide (LPS)-induced NF-κB signaling in bone marrow derived-macrophages (BMM) and determined the therapeutic efficacy of this extract on colon inflammation. LPS-induced IL-12p40, IL-23p19, IL-6 and IL-1β mRNA expressions were inhibited by BTE. LPS-induced IκBα phosphorylation/degradation and nuclear translocation of NF-κB/p65 were blocked by BTE. BTE treatment blocked LPS-induced DNA-binding activity of NF-κB. BTE-fed, DSS-exposed mice showed the less weight loss, longer colon length and lower histologic score compared to control diet-fed, DSS-exposed mice. DSS-induced IκBα phosphorylation/degradation and phosphorylation of NF-κB/p65 were blocked by BTE. An increase of cleaved caspase-3 and poly (ADP-ribose) polymerase (PARP) in DSS-exposed mice was blocked by BTE. These results indicate that BTE attenuates colon inflammation through the blockage of NF-κB signaling and apoptosis in DSS-induced experimental colitis model.
(n° 63) Green tea polyphenol epigallocatechin-3-gallate suppresses melanoma growth by inhibiting inflammasome and IL-1β secretion.
Ellis LZ, Liu W, Luo Y, Okamoto M, Qu D, Dunn JH, Fujita M., Biochem Biophys Res Commun. 2011 Oct 28;414(3):551-6. Epub 2011 Oct 1, University of Colorado School of Medicine, Aurora, USA.
Epigallocatechin-3-gallate (EGCG), the major polyphenolic component of green tea, has been demonstrated to possess anti-inflammatory, antioxidant, anti-mutagenic and anti-carcinogenic properties. The anti-melanoma effect of EGCG has been previously suggested, but no clear mechanism of action has been established. In this study, we demonstrated that EGCG inhibits melanoma cell growth at physiological doses (0.1-1 μM). This paper provides a novel mechanism for EGCG-induced melanoma inhibition: inflammasome downregulation→decreased IL-1β secretion→decreased NF-κB activities→decreased cell growth. In addition, it suggests inflammasomes and IL-1β could be potential targets for future melanoma therapeutics.
(n° 64) (-)-Epigallocatechin gallate suppresses proliferation of vascular smooth muscle cells induced by high glucose by inhibition of PKC and ERK1/2 signalings.
Yang J, Han Y, Sun H, Chen C, He D, Guo J, Yu C, Jiang B, Zhou L, Zeng C., J Agric Food Chem. 2011 Nov 9;59(21):11483-90. Epub 2011 Oct 14, The Third Military Medical University, Chongqing, People's Republic of China.
Proliferation of vascular smooth muscle cells (VSMCs) plays an important role in the development and progression of diabetes-related vascular complications. (-)-Epigallocatechin gallate (EGCG), the major catechin derived from green tea, is able to exert antidiabetes effects in animal models. However, it is not known whether or not EGCG inhibits VSMC proliferation induced by high glucose. This study tested the hypothesis that EGCG might have an inhibitory effect on VSMC proliferation induced by high glucose. VSMC proliferation was determined by [(3)H]-thymidine incorporation and uptake of 3-(4,5-dimethylthiazol-2-yl)-diphenyltetrazolium bromide (MTT). VSMC proliferation mediated by high glucose (30 mM) was involved in protein kinase C (PKC) and ERK1/2 signalings, because its effect was blocked by PKC inhibitor (PKC inhibitor 19-31) and ERK1/2 inhibitor (PD98059). Pretreatment of VSMCs with EGCG significantly inhibited the stimulatory effect of high glucose on PKC and ERK1/2 activation, followed by attenuation of its downstream transcription factor Elk-1 phosphorylation. Taken together, these results suggest that EGCG could suppress VSMC proliferation induced by high glucose by inhibition of PKC and ERK1/2 signalings in VSMCs, which indicates that EGCG might be a possible medicine to reduce vascular complications in diabetes.
(n° 65) Green tea polyphenols produce antidepressant-like effects in adult mice.
Zhu WL, Shi HS, Wei YM, Wang SJ, Sun CY, Ding ZB, Lu L., Pharmacol Res. 2012 Jan;65(1):74-80. Epub 2011 Sep 22, Peking University, Beijing, China.
Recent studies have shown that a higher consumption of green tea leads to a lower prevalence of depressive symptoms in elderly individuals. However, no studies have explored the antidepressant-like effect of green tea in preclinical models of depression. The aim of this study was to investigate the antidepressant-like effects and the possible mechanism of action of green tea in widely used mouse models of depression. Mice were orally administered green tea polyphenols (GTP; 5, 10 and 20mg/kg) for 7days and assessed in the forced swimming test (FST) and tail suspension test (TST) 60min after the last GTP administration. Serum corticosterone and adrenocorticotrophic hormone (ACTH) levels were also determined immediately after the FST. Green tea polyphenols significantly reduced immobility in both the FST and TST but did not alter locomotor activity in the open field test, suggesting that GTP has antidepressant-like effects, and this action did not induce nonspecific motor changes in mice. Green tea polyphenols also reduced serum corticosterone and ACTH levels in mice exposed to the FST. The present study demonstrated that GTP exerts antidepressant-like effects in a mouse behavioral models of depression, and the mechanism may involve inhibition of the hypothalamic-pituitary-adrenal axis.
(n° 66) Effect of green tea (Camellia Sinensis L.) extract on morphological and functional changes in adult male gonads of albino rats.
Chandra AK, Choudhury SR, De N, Sarkar M., Indian J Exp Biol. 2011 Sep;49(9):689-97, University College of Science and Technology, University of Calcutta, Kolkata, West Bengal, India.
Green tea, prepared from the steamed and dried leaves of the shrub Camellia Sinensis, is known for its antioxidant and anti-carcinogenic effects. However, its effects on male gonadal functions have not been explored adequately and the present investigation has been undertaken to evaluate the effect of green tea extract on gonads of adult male albino rats. Results of in vivo studies showed that green tea extract (GTE) at mild (1.25 g%, identical to 5 cups of tea/day), moderate (2.5 g%, identical to 10 cups of tea/day) and high (5.0 g%, identical to 20 cups of tea/day) doses, for a period of 26 days, altered morphology and histology of testis and accessory sex organs. A significant dose-dependent decrease in the sperm counts, inhibited activities of testicular delta(5)3beta-and 17beta-hydroxysteroid dehydrogenase (delta5-3beta3-HSD and 17beta3-HSD respectively) and decreased serum testosterone level were noticed. Significant increase in serum LH level was observed after moderate and high doses; serum FSH level also increased but not significantly. Histopathological examination showed inhibition of spermatogenesis evidenced by preferential loss of matured and elongated spermatids. Results of this study showed that GTE at relatively high dose may cause impairment of both the morphological and normal functional status of testis in rodents and thus its consumption at relatively high doses raises concern on male reproductive function in spite of its other beneficial effects.
(n° 67) Anti-obesity effects of the methanolic extract and chakasaponins from the flower buds of Camellia Sinensis in mice.
Hamao M, Matsuda H, Nakamura S, Nakashima S, Semura S, Maekubo S, Wakasugi S, Yoshikawa M., Bioorg Med Chem. 2011 Oct 15;19(20):6033-41. Epub 2011 Aug 25., Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto, Japan.
The methanolic extract from the flower buds of Camellia Sinensis cultivated in Fujian Province showed inhibitory effects on body weight gain and the weight of visceral fats in high-fat diet-fed mice and/or Tsumura Suzuki Obese Diabetic (TSOD) mice. A suppressive effect of the extract on food intake was suggested to contribute to the anti-obesity effect. The n-butanol (BuOH)-soluble fraction also reduced food intake in normal diet-fed mice. A principal constituent, chakasaponin II, inhibited gastric emptying (GE) as well as food intake. These inhibitory effects were partly reduced by pretreatment with a high dose of capsaicin. The n-BuOH-soluble fraction and chakasaponin II suppressed mRNA levels of neuropeptide Y (NPY), an important regulator of body weight through its effects on food intake and energy expenditure, in the hypothalamus. Furthermore, chakasaponin II enhanced the release of serotonin (5-HT) from the isolated ilea of mice in vitro. These findings suggested that the active saponins suppressed the appetite signals in the hypothalamus through stimulation of the capsaicin-sensitive sensory nerves, probably vagal afferent nerves, or enhancement of 5-HT release from the ilea, leading to reduced food intake and body weight gain.
(n° 68) Effect of supplementation of soft drinks with green tea extract on their erosive potential against dentine.
Barbosa CS, Kato MT, Buzalaf MA., Aust Dent J. 2011 Sep;56(3):317-21. doi: 10.1111/j.1834-7819.2011.01338.x. Epub 2011 Jul 20, University of São Paulo, Bauru, Brazil.
Matrix metalloproteinase (MMP) inhibitors reduce dentine erosion. This in vitro study evaluated the effect of the supplementation of soft drinks with green tea extract, a natural inhibitor of MMPs, on their erosive potential against dentine. For each drink tested (Coca-Cola, Kuat guarana, Sprite and light Coca-Cola), 40 dentine specimens were divided into two subgroups differing with respect to supplementation with green tea extract at 1.2% (OM24, 100%Camellia Sinensis leaf extract, containing 30 ± 3% of catechin; Omnimedica, Switzerland) or not (control). A significant difference was observed among the drinks tested with Sprite leading to the highest surface loss and light Coca-Cola to the lowest. Supplementation with green tea extract reduced the surface loss by 15% to 40% but the difference was significant for Coca-Cola only. Supplementation of soft drinks with green tea extract might be a viable alternative to reduce their erosive potential against dentine.
(n° 69) Pro-bone and antifat effects of green tea and its polyphenol, epigallocatechin, in rat mesenchymal stem cells in vitro.
Ko CH, Siu WS, Wong HL, Shum WT, Fung KP, San Lau CB, Leung PC., J Agric Food Chem. 2011 Sep 28;59(18):9870-6. Epub 2011 Sep 6, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
Green tea has been demonstrated recently as a potent bone supportive agent. Our previous studies showed that green tea and its polyphenolic constituents can promote bone-forming osteoblast activities and inhibit the bone-resorpting osteoclast formation. The objective of the present study was to investigate whether green tea and its components can regulate the osteogenic and adipogenic differentiation in pluripotent rat mesenchymal stem cells (MSCs). Our results demonstrated that GTE could significantly increase ALP dose dependently in the concentrations without cytotoxicity (0-100 μg/mL). Among six tested tea polyphenols, epigallocatechin (EGC) was shown to be the most effective in promoting osteogenic differentiation. At 20 μM, EGC increased ALP levels and Ca deposition significantly by 2.3- and 1.7-fold, respectively, when compared with the control group. EGC also increased the mRNA expression of bone formation markers runt-related transcription factor 2, ALP, osteonectin, and osteopontin. Furthermore, EGC demonstrated its antiadipogenicity by decreasing the adipocyte formation and inhibiting the mRNA expression levels of the adipogenic markers peroxisome proliferator-activated receptor γ, ccaat/enhancer-binding protein β, and fatty acid binding protein 4. In conclusion, this is the first report of the dual action of green tea polyphenol EGC in promoting osteogenesis and inhibiting adipocyte formation in MSCs. Our results provide scientific evidence to support the potential use of green tea in supporting the bone against degenerative diseases such as osteoporosis.
(n° 70) Anti-hyperglycemia properties of Tea (Camellia Sinensis) bioactives using in vitro assay models and influence of extraction time.
Ankolekar C, Terry T, Johnson K, Johnson D, Barbosa AC, Shetty K., J Med Food. 2011 Oct;14(10):1190-7. Epub 2011 Aug 22, Chenoweth Laboratory, University of Massachusetts, Amherst, Massachusetts, USA.
Tea (Camellia Sinensis) has well-known health benefits, which are attributed to its polyphenolic metabolites. This research explored the potential of regular tea consumption and influence of extraction time typically used in daily consumption of tea, as a therapeutic dietary support for potential management of early stage type 2 diabetes using in vitro assay models. The most fermented teas showed highest α-amylase inhibition: Choice Darjeeling 5-minute extraction had the highest inhibition (84.1%), followed by Tazo Black 5-minute extraction (71.6%). Angiotensin converting enzyme inhibition was not observed in any sample. Overall, the 5-minute extraction time was found to have more relevance for potential benefits for managing hyperglycemia than the 2-minute procedure. This research suggests that tea offers an attractive potential strategy to regulate postprandial hyperglycemia toward an overall dietary support for type 2 diabetes management.
(n° 71) Protocol for minimizing the risk of metachronous adenomas of the colorectum with green tea extract (MIRACLE): a randomised controlled trial of green tea extract versus placebo for nutriprevention of metachronous colon adenomas in the elderly population.
Stingl JC, Ettrich T, Muche R, Wiedom M, Brockmöller J, Seeringer A, Seufferlein T., BMC Cancer. 2011 Aug 18;11:360, University Ulm, Germany. Julia.firstname.lastname@example.org
Prevention of colorectal cancer is a major health care issue. People who have undergone colonoscopy screening and had colorectal polyps removed have a higher risk of being diagnosed with polyps again compared to the normal population. Therefore, it would be ideal to find appropriate means that effectively help to prevent the reoccurrence of polyps after polypectomy. So far, pharmaceutical chemoprevention with NSAIDs including aspirin has been shown to be effective but not gained general acceptance due to side effects. Nutraceuticals such as polyphenols from tea plants have demonstrated remarkable therapeutic and preventive effects in molecular, epidemiological and clinical trials. However, placebo-controlled trials demonstrating the efficacy of nutraceuticals for the (secondary) prevention of colorectal polyps as precursors for colorectal cancer are missing. The beneficial safety profile of decaffeinated green tea extract, the quantifiable and known active content EGCG, and the accumulating evidence of its cancer preventive potential require, in our view, a validation of this compound for the nutriprevention of colorectal adenoma. Good accessibility and low costs might render this neutraceutical a top candidate for wider use as food supplement in colon cancer prevention.
(n° 72) Green tea catechin, epigallocatechin-3-gallate (EGCG): mechanisms, perspectives and clinical applications.
Singh BN, Shankar S, Srivastava RK., Biochem Pharmacol. 2011 Dec 15;82(12):1807-21. Epub 2011 Jul 30, The University of Kansas Cancer Center, The University of Kansas Medical Center, Kansas City, United States.
An expanding body of preclinical evidence suggests EGCG, the major catechin found in green tea (Camellia Sinensis), has the potential to impact a variety of human diseases. Apparently, EGCG functions as a powerful antioxidant, preventing oxidative damage in healthy cells, but also as an antiangiogenic and antitumor agent and as a modulator of tumor cell response to chemotherapy. Much of the cancer chemopreventive properties of green tea are mediated by EGCG that induces apoptosis and promotes cell growth arrest by altering the expression of cell cycle regulatory proteins, activating killer caspases, and suppressing oncogenic transcription factors and pluripotency maintain factors. EGCG has great potential in cancer prevention because of its safety, low cost and bioavailability. In this review, we discuss its cancer preventive properties and its mechanism of action at numerous points regulating cancer cell growth, survival, angiogenesis and metastasis. Therefore, non-toxic natural agent could be useful either alone or in combination with conventional therapeutics for the prevention of tumor progression and/or treatment of human malignancies.
(n° 73) Amelioration of behavioral aberrations and oxidative markers by green tea extract in valproate induced autism in animals.
Banji D, Banji OJ, Abbagoni S, Hayath MS, Kambam S, Chiluka VL., Brain Res. 2011 Sep 2;1410:141-51. Epub 2011 Jul 5, Nalanda College of Pharmacy, Cherlapally, Nalgonda, India.
Exposure to toxicants prenatally and postnatally could have deleterious consequences on the offspring. Postnatal exposure to valproate in mice pups is capable of inducing experimental autism resulting in neurobehavioral aberrations. Consumption of green tea has been associated with neuronal protection against the impact of toxicants. We investigated the role of green tea extract in reversing cardinal behavioral changes and aberrations in oxidative stress induced by valproate exposure. Young mice of both genders received a single dose of valproate (400mg/kg subcutaneously) on postnatal day 14 followed by a daily dose of green tea extract (75 and 300mg/kg) orally up to postnatal day 40. Mice pups were subjected to behavioral testing to assess motor co-ordination, nociceptive response, locomotion, anxiety, exploratory activity and cognition on various postnatal days up to postnatal day 40. At the end of behavioral testing, blood was withdrawn from the retro orbital plexus for the estimation of lipid peroxides. Animals were sacrificed on postnatal day 41 and whole brain was subjected to histopathological examination. Our studies revealed a significant improvement in behavioral assessments particularly with 300mg/kg of green tea extract. Formation of markers of oxidative stress was reduced at both dose levels. Histological findings confirm the neuroprotective effect of green tea at a dose of 300mg/kg. In conclusion it can be stated that green tea exerts neuronal cytoprotective action possibly due to anti-oxidant action and could be efficacious in the management of autism.
(n° 74) Effects of the aqueous extract of white tea (Camellia Sinensis) in a streptozotocin-induced diabetes model of rats.
Islam MS., Phytomedicine. 2011 Dec 15;19(1):25-31. Epub 2011 Jul 30, University of KwaZulu-Natal (Westville Campus), Durban, South Africa.
White tea (WT) is very similar to green tea (GT) but it is exceptionally prepared only from the buds and young tea leaves of Camellia Sinensis plant while GT is prepared from the matured tea leaves. The present study was investigated to examine the effects of a 0.5% aqueous extract of WT in a streptozotocin-induced diabetes model of rats. Data of this study suggest that the 0.5% aqueous extract of WT is effective to reduce most of the diabetes associated abnormalities in a steptozotocin-induced diabetes model of rats.
(n° 75) Retardation of quality changes of Pacific white shrimp by green tea extract treatment and modified atmosphere packaging during refrigerated storage.
Nirmal NP, Benjakul S., Int J Food Microbiol. 2011 Oct 3;149(3):247-53. Epub 2011 Jul 8, Prince of Songkla University, Hat Yai, Songkhla, Thailand.
The effect of modified atmosphere packaging (MAP) on the quality changes of Pacific white shrimp (Litopenaeus vannamei) treated with or without green tea extract (1g/L; GTE) in combination with or without ascorbic acid (0.05g/L; AA) during refrigerated storage of 10days was investigated. GTE treatment in combination with MAP could retard chemical changes and melanosis formation, regardless of AA incorporation (P>0.05). Nevertheless, GTE in combination with AA had higher inhibition on microbial growth and yielded the shrimp with higher likeness, compared with the other treatments (P<0.05). Therefore, shrimp treated with GTE in combination with AA prior to MAP had the lowest losses in quality during refrigerated storage.
(n° 76) Tea triterpenoidal saponins from the roots of Camellia Sinensis have inhibitory effects against alcohol dehydrogenase.
Varughese T, Manir MM, Rahaman M, Kim JK, Lee BG, Moon SS., Planta Med. 2011 Dec;77(18):2029-36. Epub 2011 Jul 22, Kongju National University, Gongju, Republic of Korea.
Ten new polyhydroxyolean-12-ene pentacyclic triterpenoidal saponins, named rogchaponins 1-10, were isolated from the methanolic extract of the roots of Camellia Sinensis by a series of chromatographic methods (silica gel flash column and C18 MPLC followed by C18 HPLC). Their structures were established by 1D and 2D-NMR techniques along with IR and HR-TOF-MS. Rogchaponins R4 ( 4) and R5 (5) showed inhibitory activities against yeast alcohol dehydrogenase (ADH) with IC (50) values of 16.1 ± 3.2 and 15.4 ± 3.3 µM, respectively. A 4-methylpyrazole positive control exhibited an IC (50) of 2750 ± 50 µM. However, the saponins showed no inhibitory activity against yeast aldehyde dehydrogenase (ALDH).
(n° 77) Synergistic anticancer activity of curcumin and catechin: an in vitro study using human cancer cell lines.
Manikandan R, Beulaja M, Arulvasu C, Sellamuthu S, Dinesh D, Prabhu D, Babu G, Vaseeharan B, Prabhu NM., Microsc Res Tech. 2012 Feb;75(2):112-6. doi: 10.1002/jemt.21032. Epub 2011 Jul 21, Alagappa University, Karaikudi, Tamil Nadu, India.
The most practical approach to reduce morbidity and mortality of cancer is to delay the process of carcinogenesis by usage of anticancer agents. This necessitates that safer compounds are to be critically examined for anticancer activity especially, those derived from natural sources. A spice commonly found in India and the surrounding regions, is turmeric, derived from the rhizome of Curcuma longa and the major active component is a phytochemical termed curcumin. Green tea is one of the most popular beverages used worldwide, produced from the leaves of evergreen plant Camellia Sinensis and the major active ingredients are polyphenolic compounds known as catechins. Although, both curcumin or catechin inhibited the growth of above cell lines, interestingly, in combination of both these compounds highest level of growth control was observed. The anticancer activity shown is due to cytotoxicity, nuclear fragmentation as well as condensation, and DNA fragmentation associated with the appearance of apoptosis. These results suggest that curcumin and catechin in combination can inhibit the proliferation of HCT 15, HCT 116, as well as Hep G-2 cells efficiently through induction of apoptosis.
(n° 78) Inhibition of angiotensin converting enzyme (ACE) activity by polyphenols from tea (Camellia Sinensis) and links to processing method.
Dong J, Xu X, Liang Y, Head R, Bennett L., Food Funct. 2011 Jun;2(6):310-9. Epub 2011 May 26, CSIRO Food and Nutritional Sciences, Werribee, Victoria, Australia.
The focus of this study was to investigate Angiotensin Converting Enzyme (ACE) inhibiting activity across 34 teas (Camellia Sinensis) produced by 5 different processing methods including green (GT), oolong (OT), white (WT), black (BT) and dark (DT) teas. Inhibition was weakly dependent on substrate concentration for GT fraction >3 kDa and independent of substrate concentration for all other GT and BT size fractions and GTPI. Furthermore, evidence for direct inactivation of ACE by GTPI was demonstrated. Overall, the results suggest that tea polyphenolics exert a mixed mode of in vitro inhibition of ACE, mostly of a kinetically uncompetitive type. The results are discussed in the context of in vivo and epidemiological evidence for regulation of blood pressure by tea consumption.
(n° 79) A subacute toxicity evaluation of green tea (Camellia Sinensis) extract in mice.
Hsu YW, Tsai CF, Chen WK, Huang CF, Yen CC., Food Chem Toxicol. 2011 Oct;49(10):2624-30. Epub 2011 Jul 13, Chung Shan Medical University, Taichung City, Taiwan.
Green tea is believed to be beneficial to health because it possesses antioxidant, antiviral and anticancer properties. The potential toxicity of green tea when administered at high doses via concentrated extracts, however, has not been completely investigated. The objective of the present study was to evaluate the safety of green tea extract in ICR mice using a subacute exposure paradigm. The results showed that oral administration of green tea extract did not cause adverse effects on body weight, organ weights, hematology, serum biochemistry, urinalysis or histopathology. Additionally, administering green tea extract via gavage significantly reduced triglyceride and cholesterol levels. These observed effects could be attributed to the high levels of catechins present in green tea as these compounds have been reported to have beneficial health effects. The no-observed-adverse-effect level for green tea extract derived from the results of the present study was 2500mg/kgbody weight/day.
(n° 80) L-Theanine: properties, synthesis and isolation from tea.
Vuong QV, Bowyer MC, Roach PD., J Sci Food Agric. 2011 Aug 30;91(11):1931-9. doi: 10.1002/jsfa.4373. Epub 2011 Mar 29, University of Newcastle, Ourimbah, NSW, Australia.
Theanine is a non-protein amino acid that occurs naturally in the tea plant (Camellia Sinensis) and contributes to the favourable taste of tea. It is also associated with effects such as the enhancement of relaxation and the improvement of concentration and learning ability. It is also linked with health benefits including the prevention of certain cancers and cardiovascular disease, the promotion of weight loss and enhanced performance of the immune system. Thus, there has been a significant rise in the demand for theanine. While theanine has been chemically and biologically synthesised, techniques to isolate theanine from natural sources remain an important area of research. In this review article, the properties and health benefits of theanine are summarised and the synthesis and isolation of theanine are reviewed and discussed. Future perspectives for the isolation of theanine from natural sources are also outlined.
(n° 81) Antioxidant properties of green tea extract protect reduced fat soft cheese against oxidation induced by light exposure.
Huvaere K, Nielsen JH, Bakman M, Hammershøj M, Skibsted LH, Sørensen J, Vognsen L, Dalsgaard TK., J Agric Food Chem. 2011 Aug 24;59(16):8718-23. Epub 2011 Jul 29, University of Copenhagen, Frederiksberg C, Denmark.
The effect of two different antioxidants, EDTA and green tea extract (GTE), used individually or in combination, on the light-induced oxidation of reduced fat soft cheeses (0.2 and 6% fat) was investigated. In samples with 0.2% fat, lipid hydroperoxides as primary lipid oxidation products were not detected, but their interference was suggested from the formation of secondary lipid oxidation products such as hexanal and heptanal. The occurrence of these oxidation markers was inhibited by spiking with 50 ppm EDTA or 750 ppm GTE, or a combination of the two prior to irradiation. In contrast, addition of 50 ppm EDTA to samples with 6% fat was ineffective, but 750 ppm GTE (alone or in combination with EDTA) strongly reduced levels of hexanal and heptanal. Accumulation of primary lipid hydroperoxides was not affected by GTE, hence antioxidative activity was ascribed to scavenging of hexanal and heptanal precursors. These radical intermediates result from hydroperoxide disintegration, and subsequent scavenging by GTE, which acts as a radical sink, corroborates the intense signal observed by electron paramagnetic resonance (EPR) spectroscopy.
(n° 82) Complementary antioxidant function of caffeine and green tea polyphenols in normal human skin fibroblasts.
Jagdeo J, Brody N., J Drugs Dermatol. 2011 Jul;10(7):753-61, SUNY Downstate Medical Center, Department of Dermatology, Brooklyn, USA.
The study of free radicals is particularly relevant in the context of human skin carcinogenesis and photoaging because of these oxidants' ability to induce DNA mutations and produce lipid peroxidation byproducts, including 4-hydroxy-2-nonenal (HNE). Therefore, it is important to identify and evaluate agents with the ability to modulate intracellular free radicals and HNE.. Using a flow cytometry-based assay, the results demonstrate that at 0.001% concentration, green tea polyphenols alone, and in combination with 0.1 mM caffeine, inhibited the upregulation of H2O2-generated free radicals and HNE in human skin fibroblasts in vitro. Caffeine alone demonstrated limited anti-oxidant properties.
(n° 83) Antimicrobial traits of tea- and cranberry-derived polyphenols against Streptococcus mutans.
Yoo S, Murata RM, Duarte S., New York University, New York, USA., Caries Res. 2011;45(4):327-35. Epub 2011 Jun 30.
There are over 750 species of bacteria that inhabit the human oral cavity, but only a small fraction of those are attributed to causing plaque-related diseases such as caries. Streptococcus mutans is accepted as the main cariogenic agent and there is substantial knowledge regarding the specific virulence factors that render the organism a pathogen. Camellia Sinensis, the plant from which various forms of tea are derived, and Vaccinium macrocarpon (American cranberry fruit) have received notable attention both for their prevalence in the human diet as well as for their unique composition of polyphenols. The biologically active constituents of these plants have demonstrated potent enzyme-inhibitory properties without being bactericidal, a key quality that is important in developing therapies that will not cause microorganisms to develop resistance. The aim of this review is to consider studies that have investigated the feasibility of tea, cranberry, and other select plant derivatives as a potential basis for alternative therapeutic agents against Streptococcus mutans and to evaluate their current and future clinical relevance.
(n° 84) In vivo and in vitro antitumor effects of nutrient mixture in murine leukemia cell line P-388.
Roomi MW, Roomi NW, Bhanap B, Rath M, Niedzwiecki A., Exp Oncol. 2011 Jun;33(2):71-7, Dr. Rath's Research Institute, Cancer Division, Santa Clara, California, USA.
Leukemia is characterized by uncontrolled marrow cell proliferation and metastatic foci. We investigated the antitumor potential of a nutrient mixture on malignant leukemia P-388 cells. The nutrient mixture containing lysine, proline, ascorbic acid, green tea extract and other nutrients is formulated to target key pathways in cancer progression. Tumors in the group of mice supplemented with the nutrient mixture had 50% lower weight compared to the tumors in control group (p = 0.0105). Histopathologically, both the groups of tumors were similar, yet size of tumors in the group treated with the nutrient mixture was considerably smaller. These results indicate that the nutrient mixture exhibited significant action against multiple targets in P-388 leukemia and may have potential in human leukemia.
(n° 85) Genotoxic effects of green tea extract on human laryngeal carcinoma cells in vitro.
Durgo K, Kostić S, Gradiški K, Komes D, Osmak M, Franekić J., Arh Hig Rada Toksikol. 2011 Jun;62(2):139-46. doi: 10.2478/10004-1254-62-2011-2105, Food Technology and Biotechnology, Zagreb, Croatia.
Green tea (Camellia Sinensis) contains several bioactive compounds which protect the cell and prevent tumour development. Phytochemicals in green tea extract (mostly flavonoids) scavenge free radicals, but also induce pro-oxidative reactions in the cell. The results show that EGCG and green tea extract increased the DNA damage in the CK2 cell line during short exposure. The cytotoxicity of EGCG and ECG increased with the time of incubation. Green tea extract induced lipid peroxidation in the CK2 cell line. The pro-oxidant effect of green tea was determined at concentrations higher than those found in traditionally prepared green tea infusions.
(n° 86) Plant polyphenols attenuate hepatic injury after hemorrhage/ resuscitation by inhibition of apoptosis, oxidative stress, and inflammation via NF-kappaB in rats.
Relja B, Töttel E, Breig L, Henrich D, Schneider H, Marzi I, Lehnert M., Eur J Nutr. 2012 Apr;51(3):311-21. Epub 2011 Jun 23, Hospitals of the Goethe-University Frankfurt am Main, Frankfurt, Germany.
Oxidative stress and inflammation contribute to hepatic injury after hemorrhage/resuscitation (H/R). Natural plant polyphenols, i.e., green tea extract (GTE) possess high anti-oxidant and anti-inflammatory activities in various models of acute inflammation. However, possible protective effects and feasible mechanisms by which plant polyphenols modulate pro-inflammatory, apoptotic, and oxidant signaling after H/R in the liver remain unknown. Therefore, we investigated the effects of GTE and its impact on the activation of NF-kappaB in the pathogenesis of hepatic injury induced by H/R. Taken together, GTE application blunts hepatic damage, apoptotic, oxidative, and pro-inflammatory changes after H/R. These results underline the important roles of JNK and NF-kappaB in inflammatory processes after H/R and the beneficial impact of plant polyphenols in preventing their activation.
(n° 87) Effect of milk and brewing method on black tea catechin bioaccessibility.
van der Burg-Koorevaar MC, Miret S, Duchateau GS., J Agric Food Chem. 2011 Jul 27;59(14):7752-8. Epub 2011 Jun 28, Unilever R&D Vlaardingen, Vlaardingen, The Netherlands.
The aim of this study was to investigate whether milk reduces the bioaccessibility of tea catechins, which would compromise tea beneficial effects ascribed to polyphenols. Adding milk to black tea has been shown to lead to polyphenol-protein complexes. So far, data on the intestinal stability of polyphenol-protein complexes are scarce. English black tea (0.93 ± 0.06 mol/L total catechins) and Indian black tea (1.83 ± 0.08 mol/L catechins) were prepared with skimmed or full-fat milk and subjected to simulated gastric, small intestinal, and brush border digestion. Adding milk (5.6-40%) to tea results in a decrease of total catechin (TCAT) recovery. However, the bioaccessibilities of TCAT of tea with milk versus tea controls were comparable (p > 0.05). The type of milk did not influence TCAT recovery during all digestive stages (p > 0.05). Polyphenol-protein complexes are degraded during digestion. It is very unlikely that consumption of tea with or without milk will result in differences in catechin plasma concentration.
(n° 88) [Effects of green tea extract and its components on antioxidant status and activities of xenobiotic metabolizing enzymes of rats]. [Article in Russian]
Kravchenko LV, Trusov NV, Aksenov IV, Avren'eva LI, Guseva GV, Lashneva NV, Tutel'ian VA., Vopr Pitan. 2011;80(2):9-15.
Dietary administration of green tea extract (GTE) or epigallocatechin gallate (EGCG), quercetin (Qu) or caffeine (Cf) in doses equal to their concentration in GTE led to an increase of serum and liver antioxidant capacity and strengthening stability of microsomal and lysosomal membranes in rats. The antioxidant efficiency of EGCG and Qu was considerably higher than that of GTE. There were significant differences in the effects of EGCG, Qu and GTE on the activities and expression of mRNA for CYP1A1, CYP1A2 and CYP3A1. But feeding both GTE and Cf to rats results in similar elevated activities of CYP1A1, CYP1A2, UDP-glucuronosyl transferase and glutathion transferase. Our results suggest that Cf is the main contributor to GTE effects on activities of xenobiotic metabolizing enzymes.
(n° 89) The use of green tea extract as a storage medium for the avulsed tooth.
Hwang JY, Choi SC, Park JH, Kang SW., J Endod. 2011 Jul;37(7):962-7. Epub 2011 May 18, School of Dentistry, Kyung Hee University, Seoul, Republic of Korea.
Green tea extract (GTE) has been reported to have remarkable anti-inflammatory, antioxidant, and anticarcinogenic effects and to prolong allograft survivals. The purpose of the present study is to investigate in vitro the efficacy of GTE as a storage medium for avulsed teeth. We estimated the possibility for storage medium by maintaining the viability of human periodontal ligament (PDL) cells. The result indicates that there was no difference in cell viability between GTE and HBSS media, whereas GTE showed higher cell viability than other media (P < .05). Our study shows that the efficacy of GTE in maintaining the viability of human PDL cells is similar to that of HBSS and higher than that of milk. Therefore, we conclude that GTE could be a suitable, alternative storage medium for avulsed teeth.
(n° 90) Development of new antioxidant active packaging films based on ethylene vinyl alcohol copolymer (EVOH) and green tea extract.
Lopez de Dicastillo C, Nerin C, Alfaro P, Catala R, Gavara R, Hernandez-Munoz P., J Agric Food Chem. 2011 Jul 27;59(14):7832-40. Epub 2011 Jun 24, Instituto de Agroquímica y Tecnología de Alimentos, Paterna, Spain.
Ethylene vinyl alcohol copolymer (EVOH) films containing green tea extract were successfully produced by extrusion. The films were brown and translucent, and the addition of the extract increased the water and oxygen barrier at low relative humidity but increased the water sensitivity, the glass transition temperature, and the crystallinity of the films and improved their thermal resistance. An analysis by HPLC revealed that the antioxidant components of the extract suffered partial degradation during extrusion, reducing the content of catechin gallates and increasing the concentration of free gallic acid. Exposure of the films to various food simulants showed that the liquid simulants increased their capacity to reduce DPPH(•) and ABTS(•+) radicals. Kinetically, gallic acid was released more quickly than catechins, owing to its faster diffusivity in the polymer matrix as a consequence of its smaller molecular size, although the most relevant effect is the plasticization of the matrix by alcohol, increasing the diffusion coefficient >10-fold. Therefore, the materials here developed with the combination of antioxidant substances that constitute the green tea extract could be used in the design of antioxidant active packaging for all type of foods, from aqueous to fatty products, the compounds responsible for the protection being those with the higher compatibility with the packaged product.
(n° 91) Tea catechins prevent contractile dysfunction in unloaded murine soleus muscle: a pilot study.
Ota N, Soga S, Haramizu S, Yokoi Y, Hase T, Murase T., Nutrition. 2011 Sep;27(9):955-9. Epub 2011 Jun 8, Biological Science Laboratories, Kao Corporation, Tochigi, Japan
Extended periods of muscle disuse, physical inactivity, immobilization, and bedrest result in a loss of muscle mass and a decrease in muscle force, which are accompanied by an increase in oxidative stress. We investigated the effects of the intake of green tea catechins on unloading-induced muscle dysfunction in tail-suspended mice. Hind limb unloading caused a loss of soleus muscle weight and muscle force. Intake of tea catechins significantly inhibited the unloading-induced decrease in force in isolated soleus muscle by 19% compared with the control group, although tea catechins did not affect muscle weight. In addition, intake of tea catechins suppressed the decrease in antioxidant potential and the increase in carbonyl myofibrillar protein. Ingestion of tea catechins minimized contractile dysfunction in skeletal muscle and muscle atrophy in unloaded muscle. This effect might be partly due to the lower oxidative modification of myofibrillar protein through the antioxidant activity of tea catechins.
(n° 92) Epigallocatechin-3-gallate Inhibits Pancreatic Lipase and Reduces Body Weight Gain in High Fat-Fed Obese Mice.
Grove KA, Sae-Tan S, Kennett MJ, Lambert JD., Obesity (Silver Spring). 2011 Jun 2., The Pennsylvania State University, University Park, Pennsylvania, USA.
Tea (Camellia Sinensis, Theaceae) has been shown to have obesity preventive effects in laboratory studies. We hypothesized that dietary epigallocatechin-3-gallate (EGCG) could reverse metabolic syndrome in high fat-fed obese C57bl/6J mice, and that these effects were related to inhibition of pancreatic lipase (PL). In conclusion, EGCG supplementation reduced final BW and BW gain in obese mice, and some of these effects may be due to inhibition of PL by EGCG.
(n° 93) Search for antidiabetic constituents of medicinal food.
Nakamura S, Matsuda H, Yoshikawa M., Yakugaku Zasshi. 2011;131(6):909-15, Kyoto Pharmaceutical University, Yamashina-ku, Kyoto, Japan.
Many foods are known to have not only nutritive and taste values but also medicinal effects. In Chinese traditional medicine, the treatment using medicinal foods has been recommended highly. Recently, we examined the effects of the extract and constituents of several medicinal foods on experimental models of diabetes. In this paper, we focus on the bioactive constituents of four medicinal foods, namely the antidiabetic constituents from 1) the roots, stems and leaves of Salacia plants, 2) the male flowers of Borassus flabellifer, 3) the flower buds of Camellia Sinensis, 4) the processed leaves of Hydrangea macrophylla var. thunbergii (Hydrangeae Dulcis Folium).
(n° 94) Antimicrobial properties of green tea extract against cariogenic microflora: an in vivo study.
Ferrazzano GF, Roberto L, Amato I, Cantile T, Sangianantoni G, Ingenito A., J Med Food. 2011 Sep;14(9):907-11. Epub 2011 May 25, University of Naples Federico II, Naples, Italy.
The aim of the present study was to test in vivo the effectiveness of an experimental green tea extract in reducing levels of mutans streptococci and lactobacilli in saliva by means of selective culture medium. The experimental group showed a statistically significant reduction in colony counts of mutans streptococci and lactobacilli relative to the control group. These findings showed the efficacy of a green tea extract against cariogenic oral flora, opening a promising avenue of clinical applications in the preparation of specific and natural anticariogenic remedies.
(n° 95) Green and black tea in relation to gynecologic cancers.
Butler LM, Wu AH., Mol Nutr Food Res. 2011 Jun;55(6):931-40. doi: 10.1002/mnfr.201100058. Epub 2011 May 19, Colorado State University, Fort Collins, USA.
Observational studies have evaluated the relationship between green tea intake and cancers of the ovary and endometrium, but we are not aware of the published studies on green tea intake and risk of human papillomavirus (HPV)-related cancers of the cervix, vagina, or vulva. A critical review of the published literature on tea intake and risk of ovarian and endometrial cancers was conducted. We summarized the experimental evidence supporting the antiviral and immunomodulatory activities of green tea catechins, and results from randomized clinical trials that demonstrated green tea catechin efficacy on treatment of cervical lesions and external genital warts. Observational data support a protective role of green tea on risk of ovarian and endometrial cancers. Observational data are needed to evaluate whether green tea reduces risk of human papillomavirus-related cancers.
(n° 96) Green tea extract ameliorates reperfusion injury to rat livers after warm ischemia in a dose-dependent manner.
Liang R, Nickkholgh A, Kern M, Schneider H, Benzing S, Zorn M, Büchler MW, Schemmer P., Mol Nutr Food Res. 2011 Jun;55(6):855-63. doi: 10.1002/mnfr.201000643. Epub 2011 May 19, Ruprecht-Karls University, Heidelberg, Germany.
Polyphenolic constituents of green tea (Camellia Sinensis) have been shown to be potent scavengers of reactive oxygen species (ROS). Thus, this study was designed to assess its effects after liver ischemia-reperfusion. Preconditioning with a single oral dose of GTE ameliorates ischemia-reperfusion injury in liver. Decreased cellular activation and improved microcirculation are the proposed mechanisms.
(n° 97) Recycling coffee grounds and tea leaf wastes to improve the yield and mineral content of grains of paddy rice.
Morikawa CK, Saigusa M., J Sci Food Agric. 2011 Aug 30;91(11):2108-11. doi: 10.1002/jsfa.4444. Epub 2011 May 5, National Institute of Vegetable and Tea Science (NIVTS), Tsu, Mie, Japan.
Coffee grounds and tea leaf wastes exhibit strong affinity for metals such as Fe and Zn. The objective of this experiment was to evaluate the effect of top-dressing application of Fe- and Zn-enriched coffee grounds and tea leaf wastes at the panicle initiation stage on the mineral content of rice grains and the yield of paddy rice. The top-dressing application of these materials is an excellent method to recycle coffee grounds and tea wastes from coffee shops. Use of these novel materials would not only reduce the waste going to landfill but would also benefit the mineral nutrition of rice consumers at low cost by increasing Fe and Zn levels of rice grains as well as grain yield.
(n° 98) Modulating effects of rooibos and honeybush herbal teas on the development of esophageal papillomas in rats.
Sissing L, Marnewick J, de Kock M, Swanevelder S, Joubert E, Gelderblom W., Nutr Cancer. 2011;63(4):600-10, Medical Research Council, Tygerberg, South Africa.
Widespread consumption of herbal teas has stimulated interest in their role as cancer preventive agents. The present investigation monitored the modulation of methylbenzylnitrosamine (MBN)-induced esophageal squamous cell carcinogenesis by rooibos (Aspalathus linearis) and honeybush (Cyclopia intermedia) herbal and Camellia Sinensis teas in male F344 rats. The tumor multiplicity was significantly (P < 0.05) inhibited by unfermented honeybush (45.5%), green (50%), and black (36%) teas, while the other teas exhibited weaker effects (<30% inhibition). The mean total papilloma size was reduced by unfermented rooibos (87%), unfermented honeybush (94%), and fermented honeybush (74%) due to the absence of large papillomas (>10 mm(3)). Fermentation of herbal teas reduced the inhibitory effects on papilloma development associated with a reduction in the polyphenolic constituents. The inhibitory effect of herbal teas on papilloma development is associated with different flavonoid subgroups and/or combination thereof.
(n° 99) Mechanistic issues concerning cancer prevention by tea catechins.
Yang CS, Wang H., Mol Nutr Food Res. 2011 Jun;55(6):819-31. doi: 10.1002/mnfr.201100036. Epub 2011 Apr 29, The State University of New Jersey, Piscataway, USA.
The cancer preventive activities of tea (Camellia Sinensis, Theaceae) have been demonstrated in animal models for cancers at different organ sites and suggested by some epidemiological studies. This article discusses the key issues involved in extrapolating results from cell line studies to mechanistic information in vivo and in translating animal studies to human cancer prevention.
(n° 100) The role of antioxidant versus pro-oxidant effects of green tea polyphenols in cancer prevention.
Forester SC, Lambert JD., Mol Nutr Food Res. 2011 Jun;55(6):844-54. doi: 10.1002/mnfr.201000641. Epub 2011 May 2, The Pennsylvania State University, University Park, PA, USA.
Consumption of green tea (Camellia Sinensis) may provide protection against chronic diseases, including cancer. Green tea polyphenols are believed to be responsible for this cancer preventive effect, and the antioxidant activity of the green tea polyphenols has been implicated as a potential mechanism. The potential role of these pro-oxidant effects in the cancer preventive activity of green tea is not well understood. The evidence for not only the antioxidant, but also pro-oxidant, properties of green tea is discussed in the present review.
(n° 101) Lipophilized epigallocatechin gallate (EGCG) derivatives as novel antioxidants.
Zhong Y, Shahidi F., J Agric Food Chem. 2011 Jun 22;59(12):6526-33. Epub 2011 May 31, Memorial University of Newfoundland , St. John's, Newfoundland, Canada.
Epigallocatechin gallate (EGCG) is the major polyphenol in green tea and known to render many health benefits associated with tea consumption. EGCG was modified structurally to improve its lipophilicity, expand its application in lipophilic media, and enhance its cellular absorption in vivo. The chemical structures of the EGCG derivatives, determined by HPLC-MS and ¹H and ¹³C NMR, were EGCG-3',5',3'',5''-O-tetraesters of SA, EPA, and DHA. The lipophilized EGCG derivatives exhibited greater antioxidant activity in scavenging the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical than EGCG itself. The results suggest that EGCG derivatives may be used as potential lipophilic antioxidants in the food, cosmetic, and medicinal industries.
(n° 102) Epigallocatechin-3-gallate regulates cell growth, cell cycle and phosphorylated nuclear factor-κB in human dermal fibroblasts.
Han DW, Lee MH, Kim HH, Hyon SH, Park JC., Acta Pharmacol Sin. 2011 May;32(5):637-46. Epub 2011 Apr 25, Pusan National University, Korea.
To investigate the effects of (-)epigallocatechin-3-gallate (EGCG), the main polyphenol in green tea, on cell growth, cell cycle and phosphorylated nuclear factor-κB (pNF-κB) expression in neonatal human dermal fibroblasts (nHDFs). The effect of EGCG on the growth of nHDFs depended on the concentration tested. At a low concentration (200 μmol/L), EGCG resulted in a slight decrease in the proportion of cells in the S and G(2)/M phases of cell cycle with a concomitant increase in the proportion of cells in G(0)/G(1) phase. At the higher doses (400 and 800 μmol/L), apoptosis was induced. The regulation of EGCG on the expression of pNF-κB was also concentration-dependent, whereas it did not affect the unphosphorylated NF-κB expression. cDNA microarray analysis showed that cell cycle-related genes were down-regulated by EGCG (200 μmol/L). The expression of cyclins A/B and cyclin-dependent kinase 1 was reversibly regulated by EGCG (200 μmol/L). FITC-EGCG was found to be internalized into the cytoplasm and translocated into the nucleus of nHDFs. EGCG, through uptake into cytoplasm, reversibly regulated the cell growth and expression of cell cycle-related proteins and genes in normal fibroblasts.
(n° 103) The inhibition of the mammalian DNA methyltransferase 3a (Dnmt3a) by dietary black tea and coffee polyphenols.
Rajavelu A, Tulyasheva Z, Jaiswal R, Jeltsch A, Kuhnert N., BMC Biochem. 2011 Apr 21;12:16, Jacobs University Bremen, Bremen, Germany.
Black tea is, second only to water, the most consumed beverage globally. Previously, the inhibition of DNA methyltransferase 1 was shown by dietary polyphenols and epi-gallocatechin gallate (EGCG), the main polyphenolic constituent of green tea, and 5-caffeoyl quinic acid, the main phenolic constituent of the green coffee bean. We studied the inhibition of DNA methyltransferase 3a by a series of dietary polyphenols from black tea such as theaflavins and thearubigins and chlorogenic acid derivatives from coffee. For theaflavin 3,3 digallate and thearubigins IC50 values in the lower micro molar range were observed, which when compared to pharmacokinetic data available, suggest an effect of physiological relevance. Since Dnnmt3a has been associated with development, cancer and brain function, these data suggest a biochemical mechanism for the beneficial health effect of black tea and coffee and a possible molecular mechanism for the improvement of brain performance and mental health by dietary polyphenols.
(n° 104) Enhancement of cancer chemosensitization potential of cisplatin by tea polyphenols poly(lactide-co-glycolide) nanoparticles.
Singh M, Bhatnagar P, Srivastava AK, Kumar P, Shukla Y, Gupta KC., J Biomed Nanotechnol. 2011 Feb;7(1):202, Indian Institute of Toxicology Research, (Council of Scientific and Industrial Research, India), P.O. Box 80, M. G. Marg, Lucknow 226001, India.
Anti-cancer potential of polymer based nanoparticle of EGCG and TF alone and in combination with anti-cancer drug cisplatin have been studied in human cancer lines: A549 (lung carcinoma), HeLa (cervical carcinoma) and THP-1 (acute monocytic leukemia) using cell proliferation assay and cell cycle analysis. Encapsulated polyphenols retained biological effectiveness with over 20-fold dose advantage than EGCG/TF in exerting anti-cancer effects and also enhanced the potential of a widely used anti-cancer drug cisplatin. Subsequently, encapsulated polyphenols alone or in combination with cisplatin were more effective in inhibiting cell proliferation, metastasis, angiogenesis and apoptosis biomarkers. Collectively, our observations reveal that nanoparticle-mediated delivery of phytochemicals could serve as a basis for enhancing bioavailability and limiting the unwanted toxicity of chemotherapeutic agents.
(n° 105) Neuroprotective effects of theanine and its preventive effects on cognitive dysfunction.
Kakuda T., Pharmacol Res. 2011 Aug;64(2):162-8. Epub 2011 Apr 6, R&D Division, Itoen, Ltd., Mekami, Makinohara, Shizuoka, Japan.
Theanine (γ-glutamylethylamide) characteristically present in tea leaves (Camellia Sinensis). It has a similar chemical structure to glutamate, which is a neurotransmitter related to memory. Theanine passes through the blood-brain barrier and has been shown to have a cerebroprotective effect and a preventive effect on neuronal cell death after transient cerebral ischemia. In an investigation of elderly persons with normal or slight cognitive dysfunction, volunteers who ingested powdered green tea containing a high theanine concentration (equivalent to 47.5mgday(-1) of theanine) showed significantly lower decline in cognitive function compared with that of the placebo group. This result suggested that theanine might have improved a slight cognitive dysfunction in elderly persons.
(n° 106) Evaluation of renal protective effects of the green-tea (EGCG) and red grape resveratrol: role of oxidative stress and inflammatory cytokines.
El-Mowafy AM, Salem HA, Al-Gayyar MM, El-Mesery ME, El-Azab MF., Nat Prod Res. 2011 Apr;25(8):850-6, Mansoura University, Mansoura, Egypt.
Epigallocatechin-gallate (EGCG) and resveratrol (RSVL) are two of the most promising natural medicines. We verified their capacity to ameliorate cisplatin (CP)-induced disruption of renal glomerular filtration rate (GFR) in rats, and sought the mediatory involvement of lipid peroxidation (malondialdehyde [MDA]-level) and inflammatory cytokine (TNF-α) therein. Correlation studies showed a significant association between creatinine level, and each of MDA (r = 0.91), GSH (r = -0.87), and TNF-α (0.91). The study showed for the first time that EGCG, unlike RSVL, can protect against CP-induced nephrotoxicity. At the molecular level, CP triggers a high level of oxidative stress and systemic inflammation, events that were all abrogated with EGCG; better than RSVL or quercetin.
(n° 107) Nanoemulsified green tea extract shows improved hypocholesterolemic effects in C57BL/6 mice.
Kim YJ, Houng SJ, Kim JH, Kim YR, Ji HG, Lee SJ., J Nutr Biochem. 2012 Feb;23(2):186-91. Epub 2011 Mar 29, Korea University, Chungnam, South Korea.
Nanoemulsification of nutrients could improve bioavailability by enhancing intestinal uptake. We investigated the antioxidant and hypolipidemic effects of nanoemulsified green tea extract (NGTE). Antioxidant effect was measured by 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging assay and dichlorofluorescein diacetate (DCFH-DA) assay. C57BL/6 mice were fed a control high-fat diet, green tea extract (GTE), or NGTE diet for 4 weeks. These results suggest that nanoemulsification significantly increased hypocholesterolemic effects of GTE in vivo due to increased bioavailability.
(n° 108) Effect of tea polyphenols on microbiological and biochemical quality of Collichthys fish ball.
Yi S, Li J, Zhu J, Lin Y, Fu L, Chen W, Li X., J Sci Food Agric. 2011 Jul;91(9):1591-7. doi: 10.1002/jsfa.4352. Epub 2011 Mar 28, Zhejiang Gongshang University, Hangzhou, Zhejiang, China.
Tea polyphenols (TP), as the most active constituents of tea, are considered natural food additives. This study examined the preservative properties of TP for Collichthys fish ball in well storage. Vacuum-packed Collichthys fish balls were treated with 0, 0.1, 0.15, 0.20, 0.25, and 0.30 g kg(-1) TP and stored at 0 °C for 17 days.The shelf life of Collichthys fish balls supplemented with tea polyphenols can be prolonged for an additional 6 days in good condition at 0 °C storage.
(n° 109) Effect of green tea on pharmacokinetics of 5-fluorouracil in rats and pharmacodynamics in human cell lines in vitro.
Qiao J, Gu C, Shang W, Du J, Yin W, Zhu M, Wang W, Han M, Lu W., Food Chem Toxicol. 2011 Jun;49(6):1410-5. Epub 2011 Mar 31, Beijing Normal University, Beijing, PR China.
Tea drinking is widely practiced in the world and has recently increased among cancer patients. However, the effects of concurrent consumption of tea on the bioavailability and the net therapeutic potential of co-administered chemical drugs are not clear. In this study, the effects of green tea on the pharmacokinetics of 5-fluorouracil (5-FU) in rats and the pharmacodynamics in human cell lines in vitro were studied. The results showed that it is crucial to perform therapeutic drug monitoring (TDM) when the cancer patients have a habit of drinking green tea.
(n° 110) The impact of packaging materials on the antioxidant phytochemical stability of aqueous infusions of green tea (Camellia Sinensis) and yaupon holly (Ilex vomitoria) during cold storage.
Kim Y, Welt BA, Talcott ST., J Agric Food Chem. 2011 Sep 14;59(17):9716, Epub 2011 Mar 31, Sensus Research and Development Center, Sensus, LLC, Hamilton, Ohio, United States.
Ready to drink (RTD) teas are a growing segment in the beverage category, brought about by improvements in the flavor of these products and healthy market trends driven by consumers. The presented results evaluated the antioxidant phytochemical stability of RTD teas from aqueous infusions of traditional green tea (Camellia Sinensis) and a botanical tea from yaupon holly (Ilex vomitoria) as influenced by packaging materials during cold storage. Two common packaging materials for RTD products are glass and polyethylene terephthalate (PET) and have been compared to a retortable pouch (RP), an emerging packaging material for various types of food since it is durable, inexpensive, lightweight, and easy to sterilize. Storage stability was then evaluated for each aqueous infusion prepared at 10 g/L at 90 °C for 10 min and evaluated at 3 °C in the absence of light over 12 weeks. Results highlight the superiority of oxygen-impervious glass packaging, but viable alternatives may be utilizable for RTD teas with variable phytochemical compositions.
(n° 111) Green tea drinking is inversely associated with urinary incontinence in middle-aged and older women.
Hirayama F, Lee AH., Neurourol Urodyn. 2011 Sep;30(7):1262-5. doi: 10.1002/nau.20987. Epub 2011 Mar 14, Curtin University of Technology, Perth, Western Australia, Australia.
To investigate the association between green tea consumption and urinary incontinence among middle-aged and older women. The prevalence of urinary incontinence was 27.5% among 298 eligible participants. The 82 women who leaked urine tended to drink less green tea (daily mean intake 622, SD 554 ml) than others without the condition (daily mean intake 757, SD 571 ml), P = 0.04. Relative to non-drinkers, the adjusted odds ratios of urinary incontinence were 0.37 (95% CI 0.15-0.91) for drinking more than 700 ml and 0.34 (95% CI 0.13-0.88) for drinking 4 or more cups daily. The corresponding dose-response relationships for these quantity (P = 0.04) and frequency (P = 0.01) of intake were significant. However, association with black tea, oolong tea and coffee consumption was not evident. The findings suggested an inverse association between urinary incontinence and habitual green tea consumption in middle-aged and older women.
(n° 112) Cancer prevention by tea: Evidence from laboratory studies.
Yang CS, Wang H, Li GX, Yang Z, Guan F, Jin H., Pharmacol Res. 2011 Aug;64(2):113-22. Epub 2011 Mar 21, The State University of New Jersey, Piscataway, NJ, USA.
The cancer preventive activities of tea (Camellia Sinensis Theaceae) have been studied extensively. Inhibition of tumorigenesis by green tea extracts and tea polyphenols has been demonstrated in different animal models, including those for cancers of the skin, lung, oral cavity, esophagus, stomach, small intestine, colon, bladder, liver, pancreas, prostate, and mammary glands. Many studies in cell lines have demonstrated the modulation of signal transduction and metabolic pathways by (-)-epigallocatechin-3-gallate (EGCG), the most abundant and active polyphenol in green tea. These molecular events can result in cellular changes, such as enhancement of apoptosis, suppression of cell proliferation, and inhibition of angiogenesis. Nevertheless, the molecular mechanisms of inhibition of carcinogenesis in animals and humans remain to be further investigated. Future research directions in this area are discussed.
(n° 113) Aluminium and nutrients induce changes in the profiles of phenolic substances in tea plants (Camellia Sinensis CV TTES, No. 12 (TTE)).
Chen YM, Tsao TM, Liu CC, Lin KC, Wang MK., J Sci Food Agric. 2011 Apr;91(6):1111-7. doi: 10.1002/jsfa.4291. Epub 2011 Mar 7, National Taiwan University, Taipei, Taiwan.
Tea plants are always cultivated in acid soils in hilly regions and their growth can be dependent on to soluble aluminium (Al). The mechanism of Al detoxification and the influence of Al on phenolic compounds (i.e. catechin) in the roots of tea plants has remained obscure. This study aimed to investigate the influence of Al changes on the concentrations of phenolic substances in tea plants through hydroponic experiments. The Al concentration in tea plants indeed increases catechin concentrations and plays an important role in the growth of tea plants.
(n° 114) Anti-angiogenic activity and intracellular distribution of epigallocatechin-3-gallate analogs.
Piyaviriyakul S, Shimizu K, Asakawa T, Kan T, Siripong P, Oku N., Biol Pharm Bull. 2011 Mar;34(3):396-400, University of Shizuoka, Japan.
Angiogenesis, a process of construction of new blood capillaries, is crucial for tumor progression and metastasis. Our previous studies demonstrated that a component of green tea, epigallocatechin-3-gallate (EGCG), suppressed angiogenesis and subsequent tumor growth. In this study, to elucidate the detailed mechanism of the anti-angiogenic effect of EGCG and to enhance the antiangiogenic activity of EGCG, we designed and synthesized EGCG derivatives and examined their biological effect and intracellular localization in human umbilical vein endothelial cells (HUVECs). Abundant fluorescence was observed in the cells after a 3-h incubation, and was localized in mitochondria as well as in cytoplasm. These results suggest that EGCG was incorporated into the HUVECs, that a portion of it entered into their mitochondria.
(n° 115) EGCG stimulates autophagy and reduces cytoplasmic HMGB1 levels in endotoxin-stimulated macrophages.
Li W, Zhu S, Li J, Assa A, Jundoria A, Xu J, Fan S, Eissa NT, Tracey KJ, Sama AE, Wang H., Biochem Pharmacol. 2011 May 1;81(9):1152-63. Epub 2011 Mar 1, The Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA.
Historically, consumption of Green tea (Camellia Sinensis) has been associated with health benefits against multiple diseases including cancer, atherosclerosis and cardiovascular disorders. Emerging evidence has suggested a pathogenic role for HMGB1, a newly identified "late" mediator of lethal systemic inflammation, in the aforementioned diseases. Here we demonstrated that a major ingredient of Green tea, EGCG, was internalized into HMGB1-containing LC3-positive cytoplasmic vesicles (likely autophagosomes) in macrophages, and induced HMGB1 aggregation in a time-dependent manner. Taken together, the present study has suggested a possibility that EGCG inhibits HMGB1 release by stimulating its autophagic degradation.
(n° 116) Tea contains potent inhibitors of tyrosine phosphatase PTP1B.
Ma J, Li Z, Xing S, Ho WT, Fu X, Zhao ZJ., Biochem Biophys Res Commun. 2011 Apr 1;407(1):98-102. Epub 2011 Feb 28, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, United States.
Tea is widely consumed all over the world. Studies have demonstrated the role of tea in prevention and treatment of various chronic diseases including diabetes and obesity, but the underlying mechanism is unclear. PTP1B is a widely expressed tyrosine phosphatase which has been defined as a target for therapeutic drug development to treat diabetes and obesity. Our study suggests that some beneficial effects of tea may be attributed to the inhibition of PTP1B.
(n° 117) Effects of green tea catechins and theanine on preventing influenza infection among healthcare workers: a randomized controlled trial.
Matsumoto K, Yamada H, Takuma N, Niino H, Sagesaka YM., BMC Complement Altern Med. 2011 Feb 21;11:15, University of Shizuoka, Yada, Suruga-ku, Shizuoka, Japan.
Experimental studies have revealed that green tea catechins and theanine prevent influenza infection, while the clinical evidence has been inconclusive. This study was conducted to determine whether taking green tea catechins and theanine can clinically prevent influenza infection. The catechin/theanine group received capsules including green tea catechins (378 mg/day) and theanine (210 mg/day). The control group received placebo. Among healthcare workers for the elderly, taking green tea catechins and theanine may be effective prophylaxis for influenza infection.
(n° 118) Comparison of in vitro antioxidant activities and bioactive components of green tea extracts by different extraction methods.
Jun X, Deji S, Ye L, Rui Z., Int J Pharm. 2011 Apr 15;408(1-2):97-101. Epub 2011 Feb 12, Sichuan University, Chengdu, China.
In this study, in vitro antioxidant activities and bioactive components of green tea extracts (GTE) by ultrahigh pressure extraction and conventional extraction methods (microwave extraction, ultrasonic extraction, Soxhlet extraction and heat reflux extraction) were investigated. From the results we can draw the conclusion that not only the more bioactive components are obtained but also the extract has better free radical and reactive oxygen species scavenging activities through ultrahigh pressure extraction method. These findings further illustrate that ultrahigh pressure extraction has a bright prospect for extracting active ingredients from plant materials.
(n° 119) Interactions of green tea catechins with organic anion-transporting polypeptides.
Roth M, Timmermann BN, Hagenbuch B., Drug Metab Dispos. 2011 May;39(5):920-6. Epub 2011 Jan 28, The University of Kansas Medical Center, Kansas City, USA.
Organic anion-transporting polypeptides (OATPs) are multispecific transporters that mediate the uptake of numerous drugs and xenobiotics into cells. Here, we examined the effect of green tea (Camellia Sinensis) catechins on the function of the four OATPs expressed in human enterocytes and hepatocytes. These results indicate that two of the major flavonols found in green tea have a substantial effect on the function of OATPs expressed in enterocytes and hepatocytes and can potentially alter the pharmacokinetics of drugs and other OATP substrates. In addition, the diverse effects of EGCG on the transport of other OATP1B3 substrates suggest that different transport/binding sites are involved.
(n° 120) White tea (Camellia Sinensis Kuntze) exerts neuroprotection against hydrogen peroxide-induced toxicity in PC12 cells.
López V, Calvo MI., Plant Foods Hum Nutr. 2011 Mar;66(1):22-6, San Jorge University, Villanueva de Gállego, Zaragoza, Spain.
Tea is a popular beverage whose consumption is associated with prevention of certain disorders. The objective of the study was to investigate the potential neuroprotective effect of white tea extract (WTE) on hydrogen peroxide induced toxicity in PC12 cells. Results suggest that WTE protects PC12 cells against H(2)O(2)-induced toxicity, and that an antioxidant mechanism through ROS scavenging may be in part responsible for cells neuroprotection.
(n° 121) Green tea epigallocatechin gallate enhances therapeutic efficacy of temozolomide in orthotopic mouse glioblastoma models.
Chen TC, Wang W, Golden EB, Thomas S, Sivakumar W, Hofman FM, Louie SG, Schönthal AH., Cancer Lett. 2011 Mar 28;302(2):100-8. Epub 2011 Jan 22, University of Southern California (USC), Los Angeles, CA, USA. email@example.com
The alkylating agent temozolomide, in combination with surgery and radiation, is the current standard of care for patients with glioblastoma. However, despite this extensive therapeutic effort, the inclusion of temozolomide extends survival only by a few short months. Among the factors contributing to chemoresistance is elevated expression of the endoplasmic reticulum (ER) chaperone GRP78 (glucose-regulated protein 78; BiP), a key pro-survival component of the ER stress response system. Because the green tea component EGCG (epigallocatechin 3-gallate) had been shown to inhibit GRP78 function, we investigated whether this polyphenolic agent would be able to increase the therapeutic efficacy of temozolomide in preclinical models of glioblastoma. ER stress-regulatory components affect the chemotherapeutic response of glioblastoma cells to treatment with temozolomide, and inclusion of EGCG is able to increase the therapeutic efficacy of this DNA-damaging agent.
(n° 122) Toxic hepatitis triggered by green tea.
Rohde J, Jacobsen C, Kromann-Andersen H., Ugeskr Laeger. 2011 Jan 17;173(3):205-6, Medicinsk Afdeling, Glostrup Hospital, Denmark.
Green tea is associated with various beneficial health effects, but several cases of hepatotoxic side effects have been reported. We present the first Danish case of toxic hepatitis following the consumption of 4-6 cups of green tea per day for six months. Green tea's main chemical component is epigallocatechin gallate (EGCG). Animal studies have shown that EGCG accumulated in the liver is most toxic when consumed fasting and that it causes greater hepatotoxicity upon repeated administration. Green tea hepatotoxicity should be kept in mind and cases are notifiable to the food authorities.
(n° 123) Sterilization and protection of protein in combinations of Camellia Sinensis green tea extract and gamma irradiation.
Saloua KS, Salah K, Nasreddine B, Samia A, Mouldi S, Ahmed L., Int J Biol Macromol. 2011 Apr 1;48(3):452-8. Epub 2011 Jan 14, Laboratoire de Biochimie et de Biologie Moléculaire, Faculté des Sciences de Bizerte, Zarzouna, Tunisia.
Sterilization of milk protein without heating is of great interest. Gamma irradiation is a very powerful method to decontaminated casein. Gamma-irradiation of proteins in aqueous media at doses higher than 5kGy is known to induce their aggregation (without oxygen) or degradation (in presence of oxygen). Camellia Sinensis green tea extract addition before irradiation of caseins cow milk proteins was examined. It was found that the presence of C. Sinensis green tea extract during irradiation in the presence of oxygen conditions prevented the protein aggregation even at doses higher than 10kGy, probably by scavenging oxygen radicals produced by irradiation. The protective role of C. Sinensis green tea extract allowing the gamma-irradiation treatment of caseins cow milk proteins in solution, was asserted by sodium dodecyl-sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and by high performance liquid chromatography inverse phase (RP-HPLC). The total viable microorganisms content evaluated by Plate Count Agar (PCA) incubation for 12h at 37°C, showed that caseins protein preparations gamma-irradiated remained sterile at a dose 2kGy in absence of C. Sinensis green tea extract and at a dose lower than 2kGy in the presence of C. Sinensis green tea extract.
(n° 124) Increased plasma concentration of epigallocatechin in mice after orally administering a green tea (Camellia Sinensis L.) extract supplemented by steamed rice.
Monobe M, Ema K, Tokuda Y, Maeda-Yamamoto M., Biosci Biotechnol Biochem. 2011;75(1):152-4. Epub 2011 Jan 7, National Institute of Vegetable and Tea Science, NARO, Kanaya, Shimada, Shizuoka, Japan.
We attempted to improve the bioavailability of green tea catechins by using food ingredients. The catechin bioavailability of a green tea extract administered to mice was significantly (p<0.05) increased by supplementing with steamed rice. This enhanced bioavailability was due to the increased concentration of plasma non-gallated catechins, especially epigallocatechin (EGC).
(n° 125) Plasma pharmacokinetics of catechin metabolite 4'-O-Me-EGC in healthy humans.
Renouf M, Redeuil K, Longet K, Marmet C, Dionisi F, Kussmann M, Williamson G, Nagy K., Eur J Nutr. 2011 Oct;50(7):575-80. Epub 2011 Jan 7, Nestlé Research Center, Nestec Ltd., Vers-Chez-Les-Blanc, Lausanne, Switzerland.
Tea is an infusion of the leaves of the Camellia Sinensis plant and is the most widely consumed beverage in the world after water. Green tea contains significant amounts of polyphenol catechins and represents a promising dietary component to maintain health and well-being. Epidemiological studies indicate that polyphenol intake may have potential health benefits, such as, reducing the incidence of coronary heart disease, diabetes and cancer. While bioavailability of green tea bioactives is fairly well understood, some gaps still remain to be filled, especially the identification and quantification of conjugated metabolites in plasma, such as, sulphated, glucuronidated or methylated compounds. The quantitative results presented in our study were confirmed by co-chromatography and accurate mass analysis of the respective standards. We show that the relative abundance of 4'-O-Me-EGC is ~40% compared to the parent EGC. 4'-O-Me-EGC is an important metabolite derived from catechin metabolism. Its presence in significant amounts should not be overlooked when assessing human bioavailability of green tea.
(n° 126) Effects of Ocimum sanctum and Camellia Sinensis on stress-induced anxiety and depression in male albino Rattus norvegicus.
Tabassum I, Siddiqui ZN, Rizvi SJ., Indian J Pharmacol. 2010 Oct;42(5):283-8, Aligarh Muslim University, Aligarh, UP, India.
The aim of this study was to study the ameliorative effects of Ocimum sanctum and Camellia Sinensis on stress-induced anxiety and depression. Restraint stress (3 h/day for six consecutive days) induced a significant reduction in both the percentage number of entries and time spent in open arms in EPM, and these changes were reversed with post-treatment of aqueous extract of O. sanctum and C. Sinensis (100 mg/kg for 6 days). Restraint stress-induced (a) increased latency and (b) decreased ambulation and rearing were also reversed by O. sanctum and C. Sinensis in OFT. A significant increase in immobility period was observed in FST and TST after restraint stress. O. sanctum and C. Sinensis significantly reduced the immobility times of rats in FST and TST. O. sanctum and C. Sinensis possess anxiolytic and antidepressant activities.
(n° 127) Weight control and prevention of metabolic syndrome by green tea.
Sae-tan S, Grove KA, Lambert JD., Pharmacol Res. 2011 Aug;64(2):146-54. Epub 2010 Dec 28, The Pennsylvania State University, University Park, PA, United States.
Green tea (Camellia Sinensis, Theaceace) is the second most popular beverage in the world and has been extensively studied for its putative disease preventive effects. Green tea is characterized by the presence of a high concentrations of polyphenolic compounds known as catechins, with (-)-epigallocatechin-3-gallate (EGCG) being the most abundant and most well-studied. Metabolic syndrome (MetS) is a complex condition that is defined by the presence of elevated waist circumference, dysglycemia, elevated blood pressure, decrease serum high-density lipoprotein-associated cholesterol, and increased serum triglycerides. Studies in both in vitro and laboratory animal models have examined the preventive effects of green tea and EGCG against the symptoms of MetS. In the present review, we discuss the current state of the science with regard to laboratory studies on green tea and MetS. We attempt to critically evaluate the available data and point out areas for future research. Although there is a considerable amount of data available, questions remain in terms of the primary mechanism(s) of action, the dose-response relationships involved, and the best way to translate the results to human intervention studies.
(n° 128) In vitro protective effects of colon-available extract of Camellia Sinensis (tea) against hydrogen peroxide and beta-amyloid (Aβ((1-42))) induced cytotoxicity in differentiated PC12 cells.
Okello EJ, McDougall GJ, Kumar S, Seal CJ., Phytomedicine. 2011 Jun 15;18(8-9):691-6. Epub 2010 Dec 22, Newcastle University, Newcastle upon Tyne, United Kingdom.
There is mounting evidence that the deposition and aggregation of β-amyloid peptides (Aβ) in the brain play a significant role in the development and pathogenesis of Alzheimer's disease. There is further evidence that free radical species such as hydrogen peroxide (H(2)O(2)) mediate Aβ induced toxicity. Previous studies have demonstrated that green tea polyphenols possess neuroprotective properties through their ability to ameliorate oxidative stress induced by free radical species. Green tea polyphenols have also been shown to enhance cognition in various animal models of induced cognitive impairment. Upon ingestion, green tea polyphenols are metabolised and undergo bio-transformation which affects their bioavailability and therefore efficacy. These results demonstrate that potentially bioavailable green tea metabolites are able to ameliorate both H(2)O(2) and Aβ((1-42)) induced cytotoxicity.
(n° 129) Black tea improves attention and self-reported alertness.
De Bruin EA, Rowson MJ, Van Buren L, Rycroft JA, Owen GN., Appetite. 2011 Apr;56(2):235-40. Epub 2010 Dec 21, Unilever R&D Vlaardingen, Vlaardingen, The Netherlands.
Tea has previously been demonstrated to better help sustain alertness throughout the day in open-label studies. We investigated whether tea improves attention and self-reported alertness in two double-blind, randomised, placebo-controlled, crossover studies. Participants received black tea (made from commercially available tea bags) in one condition and placebo tea (hot water with food colours and flavours) similar in taste and appearance to real tea in the other condition. The first study also demonstrated better auditory (p<.001) and visual (p=.030) intersensory attention after black tea compared to placebo. Simulation of theanine and caffeine plasma time-concentration curves indicated higher levels in the first study compared to the second, which supports the finding that tea effects on attention were strongest in the first study. Being the second most widely consumed beverage in the world after water, tea is a relevant contributor to our daily cognitive functioning.
(n° 130) Effect on the epigallocatechin gallate/epigallocatechin ratio in a green tea (Camellia Sinensis L.) extract of different extraction temperatures and its effect on IgA production in mice.
Monobe M, Ema K, Tokuda Y, Maeda-Yamamoto M., Biosci Biotechnol Biochem. 2010;74(12):2501-3. Epub 2010 Dec 7, National Institute of Vegetable and Tea Science, NARO, Shimada, Shizuoka, Japan.
We found that the epigallocatechin gallate (EGCG)/epigallocatechin (EGC) ratio in a green tea (Camellia Sinensis L.) extract was affected by the extraction temperature. The EGCG/EGC ratio in the 4 °C extract was around 1:3-4, whereas in the 100 °C extract, it was around 1:0.7. Oral administration of the mixture with a high EGC ratio (1:2-3 = EGCG/EGC) resulted in greater IgA production by murine Peyer's patch cells.
(n° 131) The impact of the catechol-O-methyltransferase genotype on the acute responsiveness of vascular reactivity to a green tea extract.
Miller RJ, Jackson KG, Dadd T, Mayes AE, Brown AL, Minihane AM., Br J Nutr. 2012 Apr;107(7):1092, University of Reading, Whiteknights, Reading, Berkshire, UK.
The beneficial effects of green tea catechins, such as the proposed improvement in endothelial function, may be influenced by phase II metabolism during and after absorption. The methylation enzyme, catechol-O-methyltransferase (COMT), has a missense mutation rs4680 (G to A), proposed to result in a 40 % reduction in enzyme activity. In conclusion, SI and insulin response to the glucose load differed between the COMT genotype groups, and this may be suggestive of a green tea extract and genotype interaction.
(n° 132) Green tea polyphenols supplementation and Tai Chi exercise for postmenopausal osteopenic women: safety and quality of life report.
Shen CL, Chyu MC, Pence BC, Yeh JK, Zhang Y, Felton CK, Doctolero S, Wang JS., BMC Complement Altern Med. 2010 Dec 9;10:76, Texas Tech University Health Sciences Center, Lubbock, USA.
Evidence suggests that both green tea polyphenols (GTP) and Tai Chi (TC) exercise may benefit bone health in osteopenic women. However, their safety in this population has never been systematically investigated. In particular, there have been hepatotoxicity concerns related to green tea extract. This study was to evaluate the safety of 24 weeks of GTP supplementation combined with TC exercise in postmenopausal osteopenic women, along with effects on quality of life in this population. GTP at a dose of 500 mg/day and/or TC exercise at 3 hr/week for 24 weeks appear to be safe in postmenopausal osteopenic women, particularly in terms of liver and kidney functions. TC exercise for 24 weeks (3 hr/wk) significantly improved quality of life in terms of role-emotional and mental health in these subjects.
(n° 133) Biochemical characterization of epigallocatechin-3-gallate as an effective stimulator for the phosphorylation of its binding proteins by glycogen synthase kinase-3β in vitro.
Miyai S, Yamaguchi A, Iwasaki T, Shamsa F, Ohtsuki K., Biol Pharm Bull. 2010;33(12):1932-7, Kitasato University, Kanagawa, Japan.
The stimulatory and inhibitory effects of epigallocatechin-3-gallate (EGCG) and its related two compounds (luteolin and quercetin) on the phosphorylation of four proteins [bovine myelin basic protein (bMBP), human recombinant tau protein (hrTP), human recombinant vimentin (hrVM) and rat collapsin response mediator protein-2 (rCRMP-2)] by glycogen synthase kinase-3β (GSK-3β) were comparatively determined in vitro. We found that (i) EGCG, not quercetin and luteolin, highly stimulated the GSK-3β-mediated phosphorylation of hrTP and significantly stimulated the phosphorylation of bMBP and hrVM by the kinase; (ii) these three polyphenols inhibited dose-dependently the phosphorylation of rCRMP-2 by GSK-3β; (iii) only EGCG significantly enhanced autophosphorylation of GSK-3β; and (iv) EGCG had a binding-affinity with two basic proteins (bMBP and hrTP) and a low affinity with rCRMP-2 rather than hrVM in vitro. In addition, the binding of EGCG to these two basic proteins induced to highly stimulate their phosphorylation, including novel potent sites for GSK-3β, and to significantly reduce the K(m) value and increase the V(max) value of these two substrate proteins for the kinase in vitro. These results provided here suggest that EGCG acts as an effective stimulator for the GSK-3β-mediated phosphorylation of its binding proteins containing EGCG-inducible phosphorylation sites for the kinase in vitro.
(n° 134) Antiobesity effects of green tea catechins: a mechanistic review.
Rains TM, Agarwal S, Maki KC., J Nutr Biochem. 2011 Jan;22(1):1-7. Epub 2010 Nov 5, Provident Clinical Research, Glen Ellyn, IL, USA.
Green tea catechins (GTC) are polyphenolic compounds present in the unfermented dried leaves of the plant, Camellia Sinensis. Results from a number of randomized, controlled intervention trials have shown that consumption of GTC (270 mg to 1200 mg/day) may reduce body weight and fat. There are several proposed mechanisms whereby GTC may influence body weight and composition. The predominating hypothesis is that GTC influences sympathetic nervous system (SNS) activity, increasing energy expenditure and promoting the oxidation of fat. Caffeine, naturally present in green tea, also influences SNS activity, and may act synergistically with GTC to increase energy expenditure and fat oxidation. Other potential mechanisms include modifications in appetite, up-regulation of enzymes involved in hepatic fat oxidation, and decreased nutrient absorption. This article reviews the evidence for each of these purported mechanisms, with particular reference to studies in humans.
(n° 135) Green and black tea suppress hyperglycemia and insulin resistance by retaining the expression of glucose transporter 4 in muscle of high-fat diet-fed C57BL/6J mice.
Nishiumi S, Bessyo H, Kubo M, Aoki Y, Tanaka A, Yoshida K, Ashida H, Kobe University, Nada-ku, Kobe, Hyogo, Japan, J Agric Food Chem. 2010 Dec 22;58(24):12916-23. Epub 2010 Nov 24.
To investigate the preventive effects of tea on hyperglycemia and insulin resistance, male C57BL/6J mice were given a high-fat diet containing 29% lard and also green or black tea ad libitum for 14 weeks. Both teas suppressed body weight gain and deposition of white adipose tissue caused by the diet. In addition, they improved hyperglycemia and glucose intolerance by stimulating glucose uptake activity accompanied by the translocation of glucose transporter (GLUT) 4 to the plasma membrane in muscle. Long-term consumption of the high-fat diet reduced levels of insulin receptor β-subunit, GLUT4 and AMP-activated protein kinase α in muscle, and green and black tea suppressed these decreases. The results strongly suggest that green and black tea suppress high-fat diet-evoked hyperglycemia and insulin resistance by retaining the level of GLUT4 and increasing the level of GLUT4 on the plasma membrane in muscle.
(n° 136) Green tea extract-induced lethal toxicity in fasted but not in nonfasted dogs.
Wu KM, Yao J, Boring D., Int J Toxicol. 2011 Feb;30(1):19-20. Epub 2010 Nov 22, Food and Drug Administration, Silver Spring, MD, USA.
Recent chronic toxicity studies performed on green tea extracts in fasted dogs have revealed some unique dose-limiting lethal liver, gastrointestinal, and renal toxicities. Key findings included necrosis of hepatic cells, gastrointestinal epithelia and renal tubules, atrophy of reproductive organs, atrophy and necrosis of hematopoietic tissues, and associated hematological changes. The polyphenol cachetins (a mixture of primarily epigallocatechin gallate [≥55%]; plus up to 10% each of epigallocatechin, epicatechin, and epigallocatechin gallate) appeared to be the causative agents for the observed toxicities because they are the active ingredients of green tea extract studied. The toxicity mechanisms that produced lethality are not known, but the results are scientifically intriguing. Because tea drinking has become more popular in the United States and abroad, the mode of action and site of action of green tea extract-induced lethal toxicities during fasting and the role of other phytochemical components of Folia Camellia Sinensis (including nonpolyphenol fractions, which are often consumed when whole-leaf products are presented) warrant further investigation.
(n° 137) Comparative evaluation of different doses of green tea extract alone and in combination with sulfasalazine in experimentally induced inflammatory bowel disease in rats.
Byrav DS, Medhi B, Vaiphei K, Chakrabarti A, Khanduja KL., Dig Dis Sci. 2011 May;56(5):1369-78. Epub 2010 Nov 17, Postgraduate Institute of Medical Education and Research, Chandigarh, India.
The exact etiopathology of inflammatory bowel disease is still unclear. Most of the therapies present are directed towards symptomatic improvement. Surgical therapy in the form of restorative proctocolectomy is reserved for the terminal stage disease, which is unresponsive to medical therapy. The present study was conducted to evaluate the effect of green tea in experimentally induced inflammatory bowel disease. The study showed that green tea alone and in combination with sulfasalazine reduced inflammatory changes induced by tri nitro benzene sulfonic acid in rats. This reduction is associated with reduced malondialdehyde, lipid peroxidation, and TNF-α. This correlates well with both gross morphological and histopathological scores. The authors concluded that a combination of green tea extract with sulfasalazine showed greater efficacy than single drug treatment.
(n° 138) Synergy research: approaching a new generation of phytopharmaceuticals.
Wagner H., Fitoterapia. 2011 Jan;82(1):34-7. Epub 2010 Nov 12, Ludwig-Maximilians-University Munich, Munich, Germany.
The longstanding, successful use of herbal drug combinations in traditional medicine demands that we find a rationale for their comparative pharmacological and therapeutic superiority to isolated single constituents. The synergistic efficacy of these combinations can be evaluated and verified by Berenbaum's isobole method, followed by clinical studies performed in comparison with synthetic standard drugs. There are many examples of mono- and multi-extract combinations used presently, which exhibit synergistic efficiency based on multi-target mechanisms of action. Among the natural products, gallocatechins of green tea and curcuminoids of ginger are the presently favoured polyphenols for a possible future use in co-medication with antibiotics and standard anticancer drugs. The main targets were found to be COX 1+2, NF-κB, and membrane glycoproteins that belong to the ATP-binding cassette (ABC) transporter family.
(n° 139) Black tea reduces diarrhoea prevalence but decreases growth performance in enterotoxigenic Escherichia coli-infected post-weaning piglets.
Bruins MJ, Vente-Spreeuwenberg MA, Smits CH, Frenken LG., J Anim Physiol Anim Nutr (Berl). 2011 Jun;95(3):388-98. doi: 10.1111/j.1439-0396.2010.01066.x. Epub 2010 Oct 29, Unilever R&D Vlaardingen, Vlaardingen, The Netherlands.
Enterotoxigenic Escherichia coli (ETEC) is a main cause of diarrhoea in humans and piglets. In vitro, black tea extract (BTE) has anti-pathogenic properties. Anti-diarrhoeal properties of BTE were assessed in a pig model of gastrointestinal infection. In vitro, BTE delayed ETEC exponential growth, which was reversed by iron addition. Although BTE had anti-diarrhoeal properties, this effect was accompanied by impaired performance. The absence of a correlation between diarrhoea prevalence and feed intake suggests that reduced diarrhoea directly results from BTE rather than from reduced feed intake caused by BTE astringency.
(n° 140) Safety evaluation of tea (Camellia Sinensis (L.) O. Kuntze) flower extract: assessment of mutagenicity, and acute and subchronic toxicity in rats.
Li B, Jin Y, Xu Y, Wu Y, Xu J, Tu Y., J Ethnopharmacol. 2011 Jan 27;133(2):583-90. Epub 2010 Oct 27, Zhejiang University, Hangzhou, Zhejiang, China.
Tea (Camellia Sinensis (L.) O. Kuntze, Theaceae) flowers possess many physiological functions and have been used in traditional medicines for deodorization, skin care, cough suppressant and expectorant in China. However, there is a little information about its possible toxicity. The present investigation was carried out to evaluate the safety of tea flower extract by mutagenicity and acute and subchronic toxicity studies. In the subchronic toxicity study, no dose-related effects on survival, growth, hematology, blood chemistry, organ weights, or pathologic lesions were observed. These results indicate that tea flower extract does not possess mutagenic potential, and that both acute and subchronic toxicity towards animals is very low. A no-observed adverse-effect level (NOAEL) for tea flower extract is 4.0 g/kg bw/day for rats under the conditions of this study.
(n° 141) Hyperbranched acidic polysaccharide from green tea.
Yang L, Fu S, Zhu X, Zhang LM, Yang Y, Yang X, Liu H, Sun Yat-sen University, Guangzhou, China., Biomacromolecules. 2010 Dec 13;11(12):3395-405. Epub 2010 Oct 28.
An acidic tea polysaccharide (ALTPS), isolated from green tea ( Camellia Sinensis ), was characterized as a hyperbranched glycoprotein containing the acidic heteropolysaccharide chains and the protein residues from the results of UV-vis, FTIR, one- and two-dimensional NMR, GC, GC-MS, and amino acid analyses. By application of the polymer solution theory, it was revealed that ALTPS was present in a sphere-like conformation in the solutions as a result of the hyperbranched structure. The TEM image further confirmed that ALTPS existed in a spherical conformation in aqueous NaCl solution. Glucose was absorbed by ALTPS, which may be one of blood glucose lowering mechanisms of tea polysaccharides.
(n° 142) Analysis of agricultural residues on tea using d-SPE sample preparation with GC-NCI-MS and UHPLC-MS/MS.
Zhang X, Mobley N, Zhang J, Zheng X, Lu L, Ragin O, Smith CJ., J Agric Food Chem. 2010 Nov 24;58(22):11553-60. Epub 2010 Oct 20, The Coca-Cola Company, 1 Coca-Cola Plaza, Atlanta, Georgia, United States.
This study presents new sample preparation and analytical procedures for the quantification of pesticides on processed tea leaves. Twenty-seven tea samples purchased from local grocery stores were analyzed using the newly developed methods. Among the pesticides analyzed, endosulfan sulfate and kelthane were the most frequently detected by GC-NCI-MS and imidacloprid and acetamiprid by UHPLC-MS/MS in these teas. The samples were found to be relatively clean, with <1 mg/kg of total pesticide residues. The organic-labeled teas were significantly cleaner than nonorganic ones. The cost per gram of tea did not correlate with pesticide residue levels detected.
(n° 143) Amelioration of gentamicin nephrotoxicity by green tea extract in uninephrectomized rats as a model of progressive renal failure.
Salem EA, Salem NA, Kamel M, Maarouf AM, Bissada NK, Hellstrom WJ, Eladl M., Ren Fail. 2010;32(10):1210-5, Zagazig University, Zagazig, Sharkia, Egypt.
Gentamicin (GM) is an effective antibiotic against severe infection but has limitations related to nephrotoxicity. This study investigates whether green tea extract (GTE), an antioxidant, could ameliorate the nephrotoxic effect of GM in uninephrectomized rats. Injecting uninephrectomized rats with GM induced renal dysfunction as shown by significant elevations in serum creatinine and urea. Serum TNF-α and oxidative stress parameters (superoxide anion and lipid peroxides) were also significantly increased. On the contrary, antioxidative parameters [superoxide dismutase (SOD), catalase (CAT), and reduced glutathione (GSH)] were significantly decreased. Histopathological examination of renal tissue illustrated features of degeneration, marked cellular infiltration, tubular dilatation, and varying degrees of necrosis. GTE given to GM rats reduced these nephrotoxicity parameters. Serum creatinine, urea, and TNF-α were almost normalized in the GM+GTE group. The oxidative stress parameters were significantly decreased and the antioxidative parameters were significantly increased. GTE ameliorates GM-induced nephrotoxicity and oxidative damage by improving antioxidant defense and tissue integrity. Further human studies are necessary to demonstrate the antioxidant effects of GTE on renal diseases. Nevertheless, green tea (GT) may offer an inexpensive, nontoxic, and effective intervention strategy in subjects with a risk for GM-induced nephrotoxicity.
(n° 144) MicroRNA expression profile of MCF-7 human breast cancer cells and the effect of green tea polyphenon-60.
Fix LN, Shah M, Efferth T, Farwell MA, Zhang B., Cancer Genomics Proteomics. 2010 Sep-Oct;7(5):261-77, East Carolina University, Greenville, NC, U.S.A.
This study reports for the first time the microRNA expression profile of human breast cancer MCF-7 cells and the effect of green tea. Twenty three miRNAs have been identified with differential expression after a 48 h treatment with 10 μg/ml Polyphenon-60 (green tea extract). These miRNAs include miR-21 and miR-27 that were found to be down-regulated following treatment with green tea. These two miRNAs have previously been identified as being overexpressed in MCF-7 breast cancer cells, with miR-21 specifically implicated in down-regulating the tumor suppressor gene, tropomyosin-1. This data supports the hypothesis that Polyphenon-60-induced modification of the breast cancer miRNA expression profile contributes to the efficacy of green tea treatment. The resulting decrease in carcinogenesis is further supported by the altered miRNA regulation of potential oncogenes and tumor-suppressor genes.
(n° 145) Ameliorated effects of green tea extract on lead induced liver toxicity in rats.
Mehana EE, Meki AR, Fazili KM., Exp Toxicol Pathol. 2012 May;64(4):291-5. Epub 2010 Oct 14, Alexandria University, Egypt.
In the present study, the effect of green tea extract (GTE) on lead induced toxicity was studied in Sprague-Dawley rats. The activities of glutathione-S-transferase (GST) and superoxide dismutase (SOD) were used as markers to evaluate the anti oxidant status of tissues. Lead exposure was found to attenuate the antioxidant potential of liver, which was however augmented when supplemented with green tea extract. Liver enzymes ALT, AST and ALP and serum protein determinations indicated the protective effects of green tea extract. Histopathological studies of liver revealed that supplementation of green tea extract resulted in mild degeneration and congestion of the blood vessels and an enhanced regenerative capacity.
(n° 146) In vivo evaluation of black and green tea dermal products against UV radiation.
Türkoğlu M, Uğurlu T, Gedik G, Yılmaz AM, Süha Yalçin A., Drug Discov Ther. 2010 Oct;4(5):362-7, Marmara University, Istanbul, Turkey.
Aqueous extracts of black and green tea (Camellia Sinensis) were obtained by freeze-drying for this study. The extracts were evaluated based on tea quality control tests, UV, IR scans, and in vitro antioxidant capacity tests. Results led to the conclusion that freeze-dried black and green tea extracts had strong UV absorbance. Formulating those extracts into dermal gels protected the skin against UV-induced erythema. Therefore, tea extracts were found to be promising candidates for their ability to protect against the harmful effects of UV radiation, such as erythema and premature aging of the skin.
(n° 147) Green tea catechin, epigallocatechin gallate, suppresses signaling by the dsRNA innate immune receptor RIG-I.
Ranjith-Kumar CT, Lai Y, Sarisky RT, Cheng Kao C., PLoS One. 2010 Sep 22;5(9):e12878, Indiana University, Bloomington, Indiana, USA.
The Innate immune system constitutes the first line of defense against pathogen infections. The Retinoic acid-inducible gene I (RIG-I) receptor recognizes triphosphorylated ssRNAs and dsRNA to initiate downstream signaling of interferon response. However, unregulated activity of these receptors could lead to autoimmune diseases. We seek to identify small molecules that can specifically regulate RIG-I signaling. Epigallocatechin gallate (EGCG), a polyphenolic catechin present in green tea, was identified in a small molecule screen. It was found to bind RIG-I and inhibits its signaling at low micromolar concentrations in HEK293T cells. EGCG and its derivatives could have potential therapeutic use as a modulator of RIG-I mediated immune responses.
(n° 148) Supplementation of green tea catechins in dentifrices suppresses gingival oxidative stress and periodontal inflammation.
Maruyama T, Tomofuji T, Endo Y, Irie K, Azuma T, Ekuni D, Tamaki N, Yamamoto T, Morita M., Arch Oral Biol. 2011 Jan;56(1):48-53. Epub 2010 Sep 25, Okayama University Graduate School of Medicine, Okayama, Japan.
This study examined the effects of a dentifrice containing green tea catechins on gingival oxidative stress and periodontal inflammation using a rat model. Rats that had experimental periodontal inflammation showed apical migration of the junctional epithelium, alveolar bone loss and inflammatory cell infiltration in the connective tissue subjacent to the junctional epithelium at 8 weeks, whilst the control group showed no pathologic changes. Topical application of a green tea catechin-containing dentifrice reduced inflammatory cell infiltration in the periodontal lesions to a greater degree than the control dentifrice at 8 weeks. The gingiva in which green tea catechin-containing dentifrice was applied also showed a lower level of expression of hexanoyl-lysine (a marker of lipid peroxidation), nitrotyrosine (a marker of oxidative protein damage), and tumour necrosis factor-α (an indicator of pro-inflammatory cytokines) at 8 weeks compared to gingiva in which the control dentifrice was applied. Adding green tea catechins to a dentifrice may contribute to prevention of periodontal inflammation by decreasing gingival oxidative stress and expression of pro-inflammatory cytokines.
(n° 149) Novel chemotherapeutic and renal protective effects for the green tea (EGCG): role of oxidative stress and inflammatory-cytokine signaling.
El-Mowafy AM, Al-Gayyar MM, Salem HA, El-Mesery ME, Darweish MM., Phytomedicine. 2010 Dec 1;17(14):1067-75. Epub 2010 Sep 18, Mansoura University, Mansoura, Egypt.
The green tea catechin, epigallocatechin-gallate (EGCG) is a superb nature's medicine candidate. We evaluated the chemotherapeutic/chemoenhancing effects of EGCG in mice bearing the solid Ehrlich ascites carcinoma (EAC) tumor, and jointly monitored levels of serum C-reactive protein (CRP), lipid peroxidation (as malondialdehyde: MDA) and leukocytosis (LC). Besides, we verified whether; and how then, EGCG would protect against a devastating CP-induced nephrotoxicity in rats. In particular, renal proinflammatory (TNF-α) and oxidant stress signals have been investigated. This study shows remarkable cytotoxic/chemoenhancing effects for EGCG and introduces CRP as a predictor of both tumor's progression and responsiveness to chemotherapy. Further, this study is the first to reveal that EGCG can obliterate the lethal CP-induced nephrotoxicity. Mechanistically, EGCG acts by suppressing leukocytosis, systemic inflammation, oxidative stress, and their sequelae.
(n° 150) Outcomes of 3% green tea emulsion on skin sebum production in male volunteers.
Mahmood T, Akhtar N, Khan BA, Khan HM, Saeed T., Bosn J Basic Med Sci. 2010 Aug;10(3):260-4, The Islamia University of Bahawalpur, Bahawalpur, Pakistan.
This study was aimed to depict potential effects of stable formulation (water in oil emulsion), containing 3% green tea (Camellia Sinensis L) extract on skin sebum production in healthy human volunteers. It was observable that statistically significant (p < 0.5%) results were found for skin sebum production after long term application of the formulation. 3% formulation of green tea extract was ideal in all aspects and can be experienced in skin disorders like acne to further investigate its effects in unhealthy volunteers.
(n° 151) Genoprotective effects of green tea (Camellia Sinensis) in human subjects: results of a controlled supplementation trial.
Han KC, Wong WC, Benzie IF., Br J Nutr. 2011 Jan;105(2):171-9, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
Green tea is rich in polyphenolic antioxidants and has widely reported but largely unsubstantiated health benefits. In the present study, genoprotective effects of two types of green tea were studied both in an in vitro and in a human supplementation trial. For the in vitro study, human lymphocytes were pre-incubated in tea (0·005-0·1 %, w/v), washed and subjected to oxidant challenge induced by H2O2. The results indicate that green tea has significant genoprotective effects and provide evidence for green tea as a 'functional food'.
Pu-erh tea tasting in Yunnan, China: correlation of drinkers' perceptions to phytochemistry.
Ahmed S, Unachukwu U, Stepp JR, Peters CM, Long C, Kennelly E., J Ethnopharmacol. 2010 Oct 28;132(1):176-85. Epub 2010 Sep 8, Institute of Economic Botany, The New York Botanical Garden, Bronx, NY, USA.
Pu-erh (or pu'er) tea tasting is a social practice that emphasizes shared sensory experience, wellbeing, and alertness. The present study examines how variable production and preparation practices of pu-erh tea affect drinkers' perceptions, phytochemical profiles, and anti-oxidant. Significant variation was found among pu-erh samples based on: (1) agro-ecosystem mode of production by TCC (P<0.0001) and TMC (P<0.0265), (2) processing method for TCC (P<0.0001), TMC (P<0.0027), and free radical scavenging capacity (P<0.0001), (3) infusion sequence for TMC (P<0.0013), (4) taste rankings for TCC (P<0.0001), TMC (P<0.0001), and IC(50) (P<0.0059) and, (5) color rankings for TMC (P<0.0009) and IC(50) (P<0.0001). Samples rated as bitter and bitter-sweet contained the greatest TCC and free radical scavenging capacity. This research demonstrated that production environment, processing methods, and infusion sequence in preparing tea are related to the phytochemical profile, free radical scavenging activity, and flavor of tea. Findings contribute to the ethnomedical literature by supporting previous studies that have hypothesized that the taste of plants, particularly bitterness, may guide societies in the search for medicinal plants and beneficial phytochemicals.
(n° 152) Effect of different doses of un-fractionated green and black tea extracts on thyroid physiology.
Chandra AK, De N, Choudhury SR., Hum Exp Toxicol. 2011 Aug;30(8):884-96. Epub 2010 Aug 27, Endocrinology and Reproductive Physiology Laboratory, Department of Physiology, University of Calcutta, Kolkata, West Bengal, India.
Tea is a rich source of polyphenolic flavonoids including catechins, which are thought to contribute to the health benefits of it. Flavonoids have been reported to have antithyroid and goitrogenic effect. This study concludes that goitrogenic/antithyroidal potential of un-fractionated green tea extract is much more than black tea extract because of the differences in catechin contents in the tea extracts.
(n° 153) Polyphenols of Camellia sinenesis decrease mortality, hepatic injury and generation of cytokines and reactive oxygen and nitrogen species after hemorrhage/resuscitation in rats.
Lehnert M, Lind H, Zhong Z, Schoonhoven R, Marzi I, Lemasters JJ., BMC Complement Altern Med. 2010 Aug 24;10:46, Medical University of South Carolina, Charleston, SC, USA.
Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are produced during hemorrhagic shock and resuscitation (H/R), which may contribute to multiple organ failure. The Aim of this study was to test the hypothesis that green tea (Camellia sinenesis) extract containing 85% polyphenols decreases injury after H/R in rats by scavenging ROS and RNS. Female Sprague Dawley rats were given 100 mg polyphenol extract/kg body weight or Polyphenols decrease ROS/RNS formation and are beneficial after hemorrhagic shock and resuscitation.
(n° 154) White and green teas (Camellia Sinensis var. Sinensis): variation in phenolic, methylxanthine, and antioxidant profiles.
Unachukwu UJ, Ahmed S, Kavalier A, Lyles JT, Kennelly EJ., J Food Sci. 2010 Aug 1;75(6):C541-8, Lehman College, Bronx, NY, USA.
Recent investigations have associated white teas with anti-carcinogenic, immune-boosting, and antioxidative properties that may impact human health in a manner comparable to green teas. An in-depth chemical analysis of white tea types was conducted to quantify polyphenols and antioxidant potential of 8 commercially available white teas, and compare them to green tea. The results suggest certain green and white tea types have comparable levels of catechins with potential health promoting qualities. Specifically, the polyphenolic content of green teas was found to be similar to certain white tea varieties, which makes the latter tea type a potential substitute for people interested in consuming polyphenols for health reasons. Moreover, this study is among the first to demonstrate the effect subtype sampling, source of procurement, cultivation, and processing practices have on the final white tea product, as such analysis has previously been mostly carried out on green teas.
(n° 155) A gel-based proteomic analysis of the effects of green tea polyphenols on ovariectomized rats.
Shao C, Chen L, Lu C, Shen CL, Gao W., Nutrition. 2011 Jun;27(6):681-6. Epub 2010 Aug 13, Texas Tech University, Lubbock, Texas, USA.
Our recent study demonstrated the protective action of green tea polyphenols (GTPs) against bone loss in ovariectomized (OVX) rats through their antioxidant capacities to scavenge reactive oxygen species. The objective of the present study was to evaluate the alterations of liver protein profiles in estrogen-deficient middle-aged rats after GTP treatment by a gel-based proteomic approach. This may lead to understanding the mechanisms of GTPs in promoting bone health. Approximately 800 protein spots were detected. The expression levels of superoxide dismutase-1 and adenosine triphosphate synthase were 2.0-fold and 1.5-fold higher in the OVX + GTP group versus the OVX group, respectively, whereas the expression level of catechol-O-methyltransferase was 1.5-fold lower in the OVX + GTP group versus the OVX group. The changes of superoxide dismutase-1 and catechol-O-methyltransferase in individual liver samples were confirmed by western blots. Our data provide further evidence for the antioxidant role of GTPs by increasing superoxide dismutase-1 and adenosine triphosphate synthase and the estrogen-associated effect of GTPs by decreasing catechol-O-methyltransferase.
(n° 156) Which plant for which skin disease? Part 2: Dermatophytes, chronic venous insufficiency, photoprotection, actinic keratoses, vitiligo, hair loss, cosmetic indications. [Article in English, German]
Reuter J, Wölfle U, Korting HC, Schempp C., J Dtsch Dermatol Ges. 2010 Nov;8(11):866-73. doi: 10.1111/j.1610-0387.2010.07472.x, University of Freiburg, Germany.
This paper continues our review of scientifically evaluated plant extracts in dermatology. After plants effective against dermatophytes, botanicals with anti-edema effects in chronic venous insufficiency are discussed. There is good evidence from randomized clinical studies that plant extracts from grape vine leaves (Vitis vinifera), horse chestnut (Aesculus hippocastanum), sea pine (Pinus maritima) and butcher's broom (Ruscus aculeatus) can reduce edema in chronic venous insufficiency. Plant extracts from witch hazel (Hamamelis virginiana), green tea (Camellia Sinensis), the fern Polypodium leucotomos and others contain antioxidant polyphenolic compounds that may protect the skin from sunburn and photoaging when administered topically or systemically. Extracts from the garden spurge (Euphorbia peplus) and from birch bark (Betula alba) have been shown to be effective in the treatment of actinic keratoses in phase II studies. Some plant extracts have also been investigated in the treatment of vitiligo, various forms of hair loss and pigmentation disorders, and in aesthetic dermatology.
(n° 157) Protective activity of different concentration of tea polyphenols and its major compound EGCG against whole body irradiation-induced injury in mice. [Article in Chinese]
Guo S, Hu Y, Liu P, Wang Y, Guo D, Wang D, Liao H., Zhongguo Zhong Yao Za Zhi. 2010 May;35(10):1328-31, Department of Clinical Pharmacology, PLA General Hospital, Beijing, China.
To evaluate the different concentrate of tea polyphenols (TP) and its compound for irradiation-protection and investigate its mechanism. This study indicate that in comparison with non-irradiated controls, irradiation resulted in a significant reduction the spleen index (spleen weight/body weight 100), haematological parameters (RBC, WBC and PLT), activity of superoxide dismutase (SOD), and increase of malondialdehde (MDA) level in 28 days. Oral administration of TP (50 mg x kg(-1)) shown the best effect on reducing the irradiation-induced injury on mice studied, and showed a protective effect against irradiation-induced haematological parameters (RBC, WBC and PLT), the spleen index and MDA level significant reduction, and antioxidase activity (SOD) decrease.The results suggest that TP 50 mg x kg(-1) and EGCG have in vivo antioxidant potential and radioprotective activity against whole body gamma irradiation in mice. It may be concluded that TP (50% EGCG) possess good irradiation-protective and antioxidant effect.
(n° 158) Green tea polyphenols attenuating ultraviolet B-induced damage to human retinal pigment epithelial cells in vitro.
Xu JY, Wu LY, Zheng XQ, Lu JL, Wu MY, Liang YR., Invest Ophthalmol Vis Sci. 2010 Dec;51(12):6665-70. Epub 2010 Aug 11, Zhejiang University Tea Research Institute, Hangzhou, China.
To examine the protective effect of green tea polyphenols against ultraviolet B (UVB)-induced damage to retinal pigment epithelial (RPE) cells. Green tea polyphenols (GTP) was used to treat RPE cells before or after exposure to UVB. GTP effectively suppressed the decrease in viability of the UVB stressed RPE cells and the UVB suppression of survivin gene expression level. GTP alleviated mitochondria dysfunction and DNA fragmentation induced by UVB. GTP protected RPE cells from UVB damage through its increase in the survivin gene expression and its attenuation of mitochondria dysfunction and DNA fragmentation. GTP is a potential candidate for further development as a chemoprotective factor for the primary prevention of age-related eye diseases such as age-related macular degeneration.
(n° 159) Black-tea polyphenols decrease micellar solubility of cholesterol in vitro and intestinal absorption of cholesterol in rats.
Ikeda I, Yamahira T, Kato M, Ishikawa A., J Agric Food Chem. 2010 Aug 11;58(15):8591-5, Tohoku University, Sendai, Miyagi, Japan.
Administration of black-tea polyphenols (BTP) simultaneously reduced lymphatic recovery of both (3)H-cholesterol and (14)C-trioleoylglycerol in rats that were cannulated in the thoracic duct. Theaflavin (TF) and theaflavin-3,3'-digallate (TFDG) had no effect on the micellar solubility of cholesterol. The concentration of bile acid in the micelles was not influenced by the addition of any BTPs or theaflavins. These results suggest that the reduction of micellar cholesterol by BTP could be important to reducing cholesterol absorption.
(n° 160) Regular daily intake of black tea improves oxidative stress biomarkers and decreases serum C-reactive protein levels in type 2 diabetic patients.
Neyestani TR, Shariatzade N, Kalayi A, Gharavi A, Khalaji N, Dadkhah M, Zowghi T, Haidari H, Shab-bidar S, Ann Nutr Metab. 2010;57(1):40-9. Epub 2010 Jul 29, Shaheed Beheshti University of Medical Sciences, Tehran, Iran.
This study was undertaken to evaluate the possible effects of different daily doses of black tea intake on certain oxidative stress, inflammatory and metabolic biomarkers in patients with type 2 diabetes mellitus (T2DM). Serum total antioxidant capacity was enhanced similarly in both test and control groups. However, daily intake of 2 cups of BTE by the test group showed a suppressing effect on serum malondialdehyde. Serum C-reactive protein significantly decreased and glutathione levels increased following the intake of 4 cups (600 ml) of BTE a day. Regular intake of BTE had anti-oxidative and anti-inflammatory effects in patients with T2DM. These findings may, to some extent, explain the mechanisms underlying the protective effects of drinking tea against cardiovascular disease.
(n° 161) Comparative effects of EGCG, green tea and a nutrient mixture on the patterns of MMP-2 and MMP-9 expression in cancer cell lines.
Roomi MW, Monterrey JC, Kalinovsky T, Rath M, Niedzwiecki A., Oncol Rep. 2010 Sep;24(3):747-57, Dr Rath Research Institute, Santa Clara, CA, USA.
Type IV collagenase matrix metalloproteinases (MMPs), especially MMP-2 and MMP-9, have been found to promote invasion and metastasis of malignant tumors. Extracellular matrix (ECM) degradation by MMPs and increased expression of MMPs in cancer cells and tumor microvascular endothelial cells make MMPs an attractive target for cancer. Focused on a common pathomechanism of cancer growth and invasion, the disintegration of connective tissue, we used natural approaches to increase the integrity and strength of connective tissues. Utilizing the principle of nutrition synergy, we developed a novel micronutrient mixture (NM) containing lysine, proline, ascorbic acid and green tea extract. This study evaluates the potency of the components EGCG and green tea extract independently compared to that of NM on modulation of patterns of MMP-2 and MMP-9 expression in four cancer cell lines expressing MMP-2, MMP-9 or both. Human fibrosarcoma (HT-1080), hepatocellular carcinoma (SK-Hep-1), glioblastoma (T-98G), uterine leiomyosarcoma (SK-UT-1) cell lines were obtained from ATCC and grown in minimum essential medium (MEM) supplemented with 10% FBS, penicillin (100 U/ml) and streptomycin (100 mg/ml) in 24-well tissue culture plates. At near confluence, the cells were treated with agents dissolved in media and tested at concentrations indicated in triplicate at each dose. Cells were also treated with PMA 100 ng/ml to study enhanced expression of MMP-9. MMP expression was assessed by gelatinase zymography. Fibrosarcoma and hepatocellular carcinoma cells expressed both MMP-2 and MMP-9. Glioblastoma cells expressed MMP-2 and PMA treatment induced MMP-9 expression. Uterine leimyosarcoma cells expressed no MMPs but PMA induced MMP-9. NM was the most potent dose-dependent inhibitor of MMPs, followed by green tea extract and EGCG. In conclusion, these results suggest the enhanced efficacy of nutrients working in synergy to modulate complex pathways such as MMP expression.
(n° 162) Prevention of diet-induced obesity by dietary black tea polyphenols extract in vitro and in vivo.
Uchiyama S, Taniguchi Y, Saka A, Yoshida A, Yajima H., Nutrition. 2011 Mar;27(3):287-92. Epub 2010 Jun 3, Functional Food Business Project, Kirin Holdings Co, Ltd, Takasaki, Gunma, Japan.
The effects of certain tea components on the prevention of obesity in humans have recently been reported, although it is still unclear whether black tea consumption is beneficial. We obtained black tea extract (BTPE) consisting of polyphenols specific to black tea, and from it, prepared a polymerized polyphenol fraction (BTP). The effectiveness of oral administration of the BTPE was examined in in vitro and in vivo experiments. BTP and BTPE inhibited pancreatic lipase activity with an IC(50) of 15.5 and 36.4 μg/mL in vitro, respectively. BTPE suppressed increases in rat plasma triglyceride levels in a dose-dependent manner after oral administration of a lipid emulsion. Furthermore, administration of the 5% BTPE suppressed increases in body weight (P < 0.05), parametrial adipose tissue mass, and liver lipid content (reduced to 56.9% and 81.7% of control mice, respectively, P < 0.05) in mice fed a high-fat diet. The BTPE may prevent diet-induced obesity by inhibiting intestinal lipid absorption. It was suggested that the major active component in the BTPE was BTP.
(n° 163) Green tea minimally affects biomarkers of inflammation in obese subjects with metabolic syndrome.
Basu A, Du M, Sanchez K, Leyva MJ, Betts NM, Blevins S, Wu M, Aston CE, Lyons TJ., Nutrition. 2011 Feb;27(2):206-13. Epub 2010 Jun 2, Oklahoma State University, Stillwater, Oklahoma, USA.
Green tea (Camellia Sinensis) has shown to exert cardioprotective benefits in observational studies. This study suggests that the daily consumption of green tea beverage or extracts for 8 wk was well tolerated but did not affect the features of metabolic syndrome. However, green tea significantly reduced plasma serum amyloid alpha, an independent cardiovascular disease risk factor, in obese subjects with metabolic syndrome.
(n° 164) Mouthwash solutions with microencapsuled natural extracts: Efficiency for dental plaque and gingivitis.
[Article in French]
Vervelle A, Mouhyi J, Del Corso M, Hippolyte MP, Sammartino G, Dohan Ehrenfest DM., Rev Stomatol Chir Maxillofac. 2010 Jun;111(3):148-51. Epub 2010 Jun 4, The LoB5 Foundation for Research, Paris, France.
Mouthwash solutions are mainly used for their antiseptic properties. They currently include synthetic agents (chlorhexidine, triclosan, etc.) or essential oils (especially Listerine). Many natural extracts may also be used. These associate both antiseptic effects and direct action on host response, due to their antioxidant, immunoregulatory, analgesic, buffering, or healing properties. The best known are avocado oil, manuka oil, propolis oil, grapefruit seed extract, pycnogenol, aloe vera, Q10 coenzyme, green tea, and megamin. The development of new technologies, such as microencapsulation (GingiNat concept), may allow an in situ slow release of active ingredients during several hours, and open new perspectives for mouthwash solutions.
(n° 165) Preventive effects of black tea theaflavins against mouse type IV allergy.
Yoshino K, Yamazaki K, Sano M., J Sci Food Agric. 2010 Sep;90(12):1983-7, Numazu National College of Technology, Shizuoka, Japan.
Tea (Camellia Sinensis L.), one of the most popular beverages, contains various beneficial constituents. We investigated the preventive effects of black tea theaflavins, theaflavin-3-gallate (3-TF) and theaflavin-3,3'-digallate (TFDG), on oxazolone-induced type IV allergy in male ICR mice. Percutaneous administration of both 3-TF and TFDG at 0.2 mg ear(-1) showed significant preventive effects against mouse type IV allergy. Oral administration of these agents at 50 mg kg(-1) body weight also showed significant preventive effects against mouse type IV allergy. Oral administration of 3-TF and TFDG at a dose of 50 mg kg(-1) body weight prevented the increases in levels of some proinflammatory cytokines, interleukin-12 (IL-12), interferon-gamma (IFN-gamma), and tumour necrosis factor-alpha (TNF-alpha), in the sera and/or ears of mice with type IV allergy. Lowering of serum antioxidant activity in mice with allergic symptoms was also prevented by oral administration of these theaflavins at a dose of 50 mg kg(-1) body weight. The anti-allergic mechanisms of action of theaflavins involve inhibition of the fluctuations of cytokines and maintenance of antioxidant status in allergic mice. These results suggest that the theaflavins as well as catechins contribute to the anti-allergic effects of black tea.
(n° 166) Green tea supplementation affects body weight, lipids, and lipid peroxidation in obese subjects with metabolic syndrome.
Basu A, Sanchez K, Leyva MJ, Wu M, Betts NM, Aston CE, Lyons TJ., J Am Coll Nutr. 2010 Feb;29(1):31-40, Oklahoma State University, Stillwater, Oklahoma, USA.
To compare the effects of supplementation of green tea beverage or green tea extracts with controls on body weight, glucose and lipid profile, biomarkers of oxidative stress, and safety parameters in obese subjects with metabolic syndrome. Pairwise comparisons showed green tea beverage and green tea extracts caused a significant decrease in body weight and body mass index (BMI) versus controls at 8 weeks (-2.5 +/- 0.7 kg, p < 0.01, and -1.9 +/- 0.6, p < 0.05, respectively). Green tea beverage showed a decreasing trend in LDL-cholesterol and LDL/high-density lipoprotein (HDL) versus controls (p < 0.1). Green tea beverage also significantly decreased MDA and HNE (-0.39 +/- 0.06 microM, p < 0.0001) versus controls. Plasma free catechins were detectable in both beverage and extract groups versus controls at screen and at 8 weeks, indicating compliance and bioavailability of green tea catechins. Green tea beverage consumption (4 cups/d) or extract supplementation (2 capsules/d) for 8 weeks significantly decreased body weight and BMI. Green tea beverage further lowered lipid peroxidation versus age- and gender-matched controls, suggesting the role of green tea flavonoids in improving features of metabolic syndrome in obese patients.
(n° 167) Evaluation of Listeria monocytogenes survival in ice cream mixes flavored with herbal tea using Taguchi method.
Ozturk I, Golec A, Karaman S, Sagdic O, Kayacier A., Foodborne Pathog Dis. 2010 Oct;7(10):1263-7, Erciyes University, Kayseri, Turkey.
In this study, the effects of the incorporation of some herbal teas at different concentrations into the ice cream mix on the population of Listeria monocytogenes were studied using Taguchi method. The ice cream mix samples flavored with herbal teas were prepared using green tea and sage at different concentrations. Afterward, fresh culture of L. monocytogenes was inoculated into the samples and the L. monocytogenes was counted at different storage periods. Taguchi method was used for experimental design and analysis. In addition, some physicochemical properties of samples were examined. Results suggested that there was some effect, although little, on the population of L. monocytogenes when herbal tea was incorporated into the ice cream mix. Additionally, the use of herbal tea caused a decrease in the pH values of the samples and significant changes in the color values.
(n° 168) Tea catechin auto-oxidation dimers are accumulated and retained by Caco-2 human intestinal cells.
Neilson AP, Song BJ, Sapper TN, Bomser JA, Ferruzzi MG., Nutr Res. 2010 May;30(5):327-40, Purdue University, West Lafayette, IN, USA.
Despite the presence of bioactive catechin B-ring auto-oxidation dimers in tea, little is known regarding their absorption in humans. Our hypothesis for this research is that catechin auto-oxidation dimers are present in teas and are absorbable by human intestinal epithelial cells. Dimers (theasinensins [THSNs] and P-2 analogs) were quantified in commercial teas by high-performance liquid chromatography-mass spectrometry. (-)-Epigallocatechin (EGC) and (-)-epigallocatechin gallate (EGCG) homodimers were present at 10 to 43 and 0 to 62 mumol/g leaf, respectively. The EGC-EGCG heterodimers were present at 0 to 79 mumol/g. The potential intestinal absorption of these dimers was assessed using Caco-2 intestinal cells. Catechin monomers and dimers were detected in cells exposed to media containing monomers and preformed dimers. Accumulation of dimers was significantly greater than monomers from test media. Three-hour accumulation of EGC and EGCG was 0.19% to 0.55% and 1.24% to 1.35%, respectively. Comparatively, 3-hour accumulation of the EGC P-2 analog and THSNs C/E was 0.89% +/- 0.28% and 1.53% +/- 0.36%, respectively. Accumulation of P-2 and THSNs A/D was 6.93% +/- 2.1% and 10.1% +/- 3.6%, respectively. The EGCG-EGC heterodimer P-2 analog and THSN B 3-hour accumulation was 4.87% +/- 2.2% and 4.65% +/- 2.8%, respectively. One-hour retention of P-2 and THSNs A/D was 171% +/- 22% and 29.6% +/- 9.3% of accumulated amount, respectively, suggesting intracellular oxidative conversion of THSNs to P-2. These data suggest that catechin dimers present in the gut lumen may be readily absorbed by intestinal epithelium.
(n° 169) The crystal structure of the green tea polyphenol (-)-epigallocatechin gallate-transthyretin complex reveals a novel binding site distinct from the thyroxine binding site.
Miyata M, Sato T, Kugimiya M, Sho M, Nakamura T, Ikemizu S, Chirifu M, Mizuguchi M, Nabeshima Y, Suwa Y, Morioka H, Arimori T, Suico MA, Shuto T, Sako Y, Momohara M, Koga T, Morino-Koga S, Yamagata Y, Kai H., Biochemistry. 2010 Jul 27;49(29):6104-14, Kumamoto University, Oe-Honmachi, Kumamoto, Japan.
Amyloid fibril formation is associated with protein misfolding disorders, including neurodegenerative diseases such as Alzheimer's, Parkinson's, and Huntington's diseases. Familial amyloid polyneuropathy (FAP) is a hereditary disease caused by a point mutation of the human plasma protein, transthyretin (TTR), which binds and transports thyroxine (T(4)). TTR variants contribute to the pathogenesis of amyloidosis by forming amyloid fibrils in the extracellular environment. A recent report showed that epigallocatechin 3-gallate (EGCG), the major polyphenol component of green tea, binds to TTR and suppresses TTR amyloid fibril formation. However, structural analysis of EGCG binding to TTR has not yet been conducted. Here we first investigated the crystal structure of the EGCG-V30M TTR complex and found novel binding sites distinct from the thyroxine binding site, suggesting that EGCG has a mode of action different from those of previous chemical compounds that were shown to bind and stabilize the TTR tetramer structure. Furthermore, EGCG induced the oligomerization and monomer suppression in the cellular system of clinically reported TTR variants. Taken together, these findings suggest the possibility that EGCG may be a candidate compound for FAP therapy.
(n° 170) The antioxidant and pro-oxidant activities of green tea polyphenols: a role in cancer prevention.
Lambert JD, Elias RJ., Arch Biochem Biophys. 2010 Sep 1;501(1):65-72. Epub 2010 Jun 15, The Pennsylvania State University, University Park, PA, USA.
Green tea (Camellia Sinensis) is rich in catechins, of which (-)-epigallocatechin-3-gallate (EGCG) is the most abundant. Studies in animal models of carcinogenesis have shown that green tea and EGCG can inhibit tumorigenesis during the initiation, promotion and progression stages. Many potential mechanisms have been proposed including both antioxidant and pro-oxidant effects, but questions remain regarding the relevance of these mechanisms to cancer prevention. This review is meant point out understudied areas and stimulate research on the topic with the hope that insights into the mechanisms of cancer preventive activity of tea polyphenols will result.
(n° 171) Lead contamination in different varieties of tea plant (Camellia Sinensis L.) and factors affecting lead bioavailability.
Chen Y, Xu J, Yu M, Chen X, Shi J., J Sci Food Agric. 2010 Jul;90(9):1501-7, Ministry of Agriculture Key Laboratory of Non-point Source Pollution Control, Hangzhou, China.
There has been increasing concern in recent years about the concentration of lead (Pb) in tea. However, little research has been done to address questions concerning the distribution of Pb in different varieties of tea plant and the differences among tea plant varieties in their uptake and accumulation of Pb from the soil. Therefore the aim of this study was to investigate the accumulation of Pb in different tea plant varieties and the factors affecting Pb bioavailability. The results indicated that the uptake, transport and accumulation of Pb by tea plant organs were strongly governed by soil conditions and tea variety, thus providing tea producers with useful information on variety selection for the production of quality teas containing low levels of Pb.
(n° 172) Oral pretreatment with a green tea polyphenol for cardioprotection against ischemia-reperfusion injury in an isolated rat heart model.
Yanagi S, Matsumura K, Marui A, Morishima M, Hyon SH, Ikeda T, Sakata R., J Thorac Cardiovasc Surg. 2011 Feb;141(2):511-7. Epub 2010 May 23, Kyoto University Graduate School of Medicine, Kyoto, Japan.
Ischemia-reperfusion injury is among the most serious problems in cardiac surgery. Epigallocatechin-3-gallate, a major polyphenolic component of green tea, is thought to be cardioprotective through its antioxidant activities. We investigated cardioprotective effects of oral epigallocatechin-3-gallate pretreatment against ischemia-reperfusion injury in isolated rat hearts and considered possible underlying mechanisms. Oral pretreatment with epigallocatechin-3-gallate preserved cardiac function after ischemia-reperfusion, an effect that may involve its antioxidative, antiapoptotic properties, although a high dose did not lead to dramatic improvement in cardiac function. Oral epigallocatechin-3-gallate pretreatment may be a novel and simple cardioprotective method for preventing perioperative cardiac dysfunction in cardiac surgery.
(n° 173) Green and black tea inhibit cytokine-induced IL-8 production and secretion in AGS gastric cancer cells via inhibition of NF-κB activity.
Gutierrez-Orozco F, Stephens BR, Neilson AP, Green R, Ferruzzi MG, Bomser JA., Planta Med. 2010 oCT;76(15):E7. Epub 2010 May 26, The Ohio State University, Columbus, OH 43210, USA.
Consumption of tea is associated with a reduced risk for several gastrointestinal cancers. Inflammatory processes, such as secretion of IL-8 from the gastric epithelium in response to chronic chemokine or antigen exposure, serve both as a chemoattractant for white blood cells and a prerequisite for gastric carcinogenesis. Our findings demonstrate that both green and black tea extracts with distinctly different catechin profiles, are capable of disrupting the molecular link between inflammation and carcinogenesis via inhibition of NF-κB activity in AGS cells.
(n° 174) Effect of dietary tea polyphenols on growth performance and cell-mediated immune response of post-weaning piglets under oxidative stress.
Deng Q, Xu J, Yu B, He J, Zhang K, Ding X, Chen D., Arch Anim Nutr. 2010 Feb;64(1):12-21, Sichuan Agricultural University, Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ya'an, Sichuan, P.R. China.
To gain insights into the effects of tea polyphenols (TP) on growth performance and cell-mediated immune response of piglets under oxidative stress, an oxidative stress model was established by intraperitoneally injecting weaned piglets with diquat. The increment of pro-inflammatory IL-1 caused by oxidative stress was attenuated, and the concentration of serum IFN-gamma was decreased by TP-supplementation. However, the serum concentrations of anti-inflammatory cytokine, such as IL-4, were greatly enhanced by TP, which suggested an immune shift from Th1 to Th2. These findings supported the immunomodulatory potential of TP for piglets subjected to oxidative stress.
(n° 175) Antimicrobial activity of the green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) against clinical isolates of Stenotrophomonas maltophilia.
Gordon NC, Wareham DW., Int J Antimicrob Agents. 2010 Aug;36(2):129-31. Epub 2010 May 15, Division of Infection, Barts & The London NHS Trust, London, UK.
Stenotrophomonas maltophilia is increasingly recognised as an important nosocomial pathogen. Treatment options are limited due to intrinsic resistance to many antibiotics as well as concerns over toxicity of the mainstay of treatment, co-trimoxazole. Epigallocatechin-3-gallate (EGCG), the major catechin found in green tea, has been shown to have antimicrobial effects against a number of bacterial pathogens. In time-kill assays, the bactericidal activity of EGCG was analysed by viable colony counts as well as a colorimetric assay for bacterial reduction of XTT. EGCG was slowly bactericidal at 4x MIC, with a 2.5 log reduction in viable bacteria at 24h. EGCG has promising in vitro antimicrobial activity against S. maltophilia. Although the mechanism of action is not yet clear, further studies to evaluate its clinical potential and role in combination with other antimicrobial agents are warranted.
(n° 176) Green tea polyphenol epigallocatechin 3-gallate in arthritis: progress and promise.
Ahmed S., Arthritis Res Ther. 2010;12(2):208. Epub 2010 Apr 28, College of Pharmacy, 2801 W, Bancroft Street, Toledo, OH, USA.
Green tea's active ingredient, epigallocatechin 3-gallate (EGCG), has gained significant attention among scientists and has been one of the leading plant-derived molecules studied for its potential health benefits. In the present review I summarize the findings from some of the most significant preclinical studies with EGCG in arthritic diseases. The review also addresses the limitations of the dose, pharmacokinetics, and bioavailability of EGCG in experimental animals and findings related to the EGCG-drug interaction. Although these findings provide scientific evidence of the anti-rheumatic activity of EGCG, further preclinical studies are warranted before phase clinical trials could be initiated with confidence for patients with joint diseases.
(n° 177) Clinical efficacy comparison of anti-wrinkle cosmetics containing herbal flavonoids.
Chuarienthong P, Lourith N, Leelapornpisid P., Int J Cosmet Sci. 2010 Apr;32(2):99-106, Rubia Industries Limited, Samutprakarn, Thailand.
Herbal anti-wrinkle cosmetics were formulated from ginkgo (Ginkgo biloba), a mixture of tea and rooibos (Camellia Sinensis and Aspalathus linearis) and soybean (Glycine soja). The ginkgo preparation increased skin moisturization (27.88%) and smoothness (4.32%) and reduced roughness (0.4%) and wrinkles (4.63%), whereas the formula containing tea and rooibos showed the best efficacy on wrinkle reduction (9.9%). In comparison to the tea and rooibos formula, gingko significantly improved skin moisturization (P = 0.05).
(n° 178) The in vitro effects of Rooibos and Black tea on immune pathways.
Hendricks R, Pool EJ., J Immunoassay Immunochem. 2010;31(2):169-80, The University of the Western Cape, Bellville, South Africa.
The in vitro effects of Aspalathus linearis (Rooibos tea) and Camellia Sinensis (Black tea) on biomarkers of specific immune pathways were determined using whole blood culture assays. Stimulated and unstimulated whole blood cultures were incubated with tea extracts. Rooibos and Black tea addition to unstimulated whole blood cultures induced higher Interleukin-6, Interleukin-10, and Interferon gamma secretion. Addition of Rooibos tea to stimulated whole blood cultures induced higher Interleukin-6, lower Interleukin-10, and had no effect on Interferon gamma secretion. Black tea addition to stimulated whole blood cultures inhibited Interleukin-6, Interleukin-10, and Interferon gamma production. The data indicates that Rooibos and Black tea modulates immune function in vitro.
(n° 179) Epigallocatechin gallate inhibits beta amyloid oligomerization in Caenorhabditis elegans and affects the daf-2/insulin-like signaling pathway.
Abbas S, Wink M., Phytomedicine. 2010 Sep;17(11):902-9. Epub 2010 Apr 9, Heidelberg University, Heidelberg, Germany.
Epidemiological studies have repeatedly demonstrated that green tea protects against oxidative stress involved in many diseases. Health benefits of green tea are attributed to its principal active constituent, epigallocatechin gallate (EGCG). In the strain TJ356 (DAF-16::GFP) EGCG treatment induced translocation of DAF-16 from the cytoplasm into the nucleus, suggesting that EGCG may affect the daf-2/insulin-like signaling pathway. EGCG decreased the formation of lipofuscin, an aging related pigment. Also, EGCG reduced beta amyloid (Abeta) deposits and inhibited Abeta oligomerization in transgenic C. elegans (CL2006). Thus, the use of green tea and EGCG is apparently rational alternatives for protecting against ROS-mediated and age-related diseases.
(n° 180) Black tea polyphenols-mediated in vivo cellular responses during carcinogenesis.
Kumar G, Pillare SP, Maru GB., Mini Rev Med Chem. 2010 Jun;10(6):492-505, Tata Memorial Centre (TMC), Kharghar, Navi Mumbai, India.
Tea (Camellia Sinensis), a popular beverage, is consumed worldwide. The biological activities and mechanism(s) of chemopreventive effects of green tea polyphenols (monomeric catechins) have been extensively studied, while similar information regarding newly formed major black tea polyphenols (BTPs-oligomeric, polymeric) is not available. Therefore, this review focuses mainly on compiling the evidence on chemopreventive efficacy of black tea extract (BTE) / BTPs and describing their mechanism(s) of anti-initiating, anti-promoting and anti-progressor action(s) in in vivo experimental systems. Overall, the mechanism(s) implicated in the BTPs-mediated inhibition are diverse and involve effects on multiple molecular pathways and genes.
(n° 181) Green tea polyphenol suppresses tumor invasion and angiogenesis in N-butyl-(-4-hydroxybutyl) nitrosamine-induced bladder cancer.
Sagara Y, Miyata Y, Nomata K, Hayashi T, Kanetake H., Cancer Epidemiol. 2010 Jun;34(3):350-4. Epub 2010 Apr 1, Nagasaki University School of Medicine, Sakamoto, Nagasaki, Japan.
Green tea polyphenol (GTP) suppresses malignancy in bladder cancer cell lines. However, the detail of its anti-carcinogenic effect in vivo is not fully understood. This study investigated the effect of GTP on bladder tumor size and angiogenesis in mice given N-butyl-(-4-hydroxybutyl) nitrosamine (BBN), with and without GTP. The results showed that GTP had no anti-carcinogenic effect, but inhibited tumor growth and invasion in mice with established bladder cancer, at least in part through the regulation of angiogenesis. Our data suggest that GTP seems to suppress tumor development in bladder cancer.
(n° 182) Coffee, tea and caffeine intake and the risk of severe depression in middle-aged Finnish men: the Kuopio Ischaemic Heart Disease Risk Factor Study.
Ruusunen A, Lehto SM, Tolmunen T, Mursu J, Kaplan GA, Voutilainen S., Public Health Nutr. 2010 Aug;13(8):1215-20. Epub 2010 Apr 1, Kuopio Campus, University of Eastern Finland, Kuopio, Finland.
Only a few cross-sectional studies have assessed the association between coffee, tea and caffeine and the risk of depression. Our aim was to determine the association in a population-based cohort study. Coffee consumption may decrease the risk of depression, whereas no association was found for tea and caffeine intake.
(n° 183) The major green tea polyphenol, (-)-epigallocatechin-3-gallate, induces heme oxygenase in rat neurons and acts as an effective neuroprotective agent against oxidative stress.
Romeo L, Intrieri M, D'Agata V, Mangano NG, Oriani G, Ontario ML, Scapagnini G., J Am Coll Nutr. 2009 Aug;28 Suppl:492S-499S, Università del Molise, via DeSanctis, Campobasso, Italy.
Oxidative stress induced by hyperglycemia is a key factor in the pathogenesis of diabetic complications, such as neuropathy. Recently, green tea catechins have received much attention, as they can facilitate a number of antioxidative mechanisms and improve glycemic control. In cultured neurons, elevated expression of HO-1 mRNA and protein were detected after 6 hours of incubation with 25-100 microM EGCG, and its induction relates with the activation of Nrf2. Interestingly, pre-incubation (12 hours) with EGCG 50 microM resulted in an enhanced cellular resistance to glucose oxidase-mediated oxidative damage; this cytoprotective effect was considerably attenuated by zinc protoporphyrin IX, an inhibitor of heme oxygenase activity. In this study, we demonstrated that EGCG, the major green tea catechin, induced HO-1 expression in cultured neurons, possibly by activation of the transcription factor Nrf2, and by this mechanism was able to protect against oxidative stress-induced cell death.
(n° 184) Effects of green tea on iron accumulation and oxidative stress in livers of iron-challenged thalassemic mice.
Saewong T, Ounjaijean S, Mundee Y, Pattanapanyasat K, Fucharoen S, Porter JB, Srichairatanakool S., Med Chem. 2010 Mar;6(2):57-64, Chiang Mai University, Chiang Mai, Thailand.
Liver is affected by secondary iron overload in transfusions dependent b-thalassemia patients. The redox iron can generate reactive oxidants that damage biomolecules, leading to liver fibrosis and cirrhosis. Iron chelators are used to treat thalassemias to achieve negative iron balance and relieve oxidant-induced organ dysfunctions. Green tea (GT) (Camellia Sinensis) catechins exhibit anti-oxidation, the inhibition of carcinogenesis, the detoxification of CYP2E1-catalyzed HepG2 cells and iron chelation. In conclusion, green tea inhibits or delays the deposition of hepatic iron in regularly iron-loaded thalassemic mice effectively. This will prevent the iron-induced generation of free radicals via Haber-Weiss and Fenton reactions, and consequently liver damage and fibrosis. Combined chelation with green tea would be investigated in beta-thalassemia patients with iron overload.
(n° 185) Oxalate content of green tea of different origin, quality, preparation and time of harvest.
Hönow R, Gu KL, Hesse A, Siener R., Urol Res. 2010 Oct;38(5):377-81. Epub 2010 Mar 4, Federal Institute for Drugs and Medical Devices, Bonn, Germany.
The purpose of the study was to analyse the oxalate content of green tea (Camellia Sinensis) depending on origin, quality, time of harvest and preparation. Leaves reaped in the autumn when grown to full size yielded more oxalate than small and young leaves reaped in the spring. Modifications in steeping duration of tea leaves had no significant influence on the oxalate content of the beverage. Patients at risk for recurrent stone formation should take into account the oxalate content of green tea.
(n° 186) Therapeutic effects on murine oral candidiasis by oral administration of cassia (Cinnamomum cassia) preparation.
Taguchi Y, Takizawa T, Ishibashi H, Sagawa T, Arai R, Inoue S, Yamaguchi H, Abe S., Nihon Ishinkin Gakkai Zasshi. 2010;51(1):13-21, Research and Product Development Division, S & B Foods Inc., Tokyo, Japan.
We examined the effects of spices and herbs on Candida albicans growth using in vitro assay and therapeutic activity of some selected herbal preparations against murine oral candidiasis. All tested samples: lemongrass (Cymbopogon citratus), lemon balm (Melissa officinalis), thyme (Thymus vulgaris), rosemary (Rosmarinus officinalis), roselle (Hibiscus sabdariffa), green tea (Camellia Sinensis), and cassia (Cinnamomum cassia) inhibited Candida mycelial growth in vitro. The results of this assay showed that the anti-Candida activity of lemongrass, green tea, and cassia is stronger than that of the other tested herbs. Oral administration of lemongrass or green tea did not result in significant improvement in the murine oral candidiasis, while the administration of cassia improved the symptoms and reduced the number of viable Candida cells in the oral cavity. The results of in vitro Candida growth assay including GC/MS analysis suggested that cinnamaldehyde in the cassia preparation was the principal component responsible for the inhibitory activity of Candida mycelial growth. These findings suggest that oral intake of a cassia preparation is a clinical candidate for a prophylactic or therapeutic tool against oral Candida infection.
(n° 187) Effects of epigallocatechin gallate on regulatory T cell number and function in obese v. lean volunteers.
Yun JM, Jialal I, Devaraj S., Br J Nutr. 2010 Jun;103(12):1771-7. Epub 2010 Feb 23, University of California, Davis, Medical Center, Sacramento, CA, USA.
Obesity predisposes to an increased incidence of diabetes and CVD. Also, obesity is a pro-inflammatory state. Regulatory T cells (Tregs) are essential negative regulators of inflammation and are down-regulated in pro-inflammatory states. Animal models of obesity are associated with decreased Tregs. The dietary modulation of Tregs could be used as a therapeutic strategy to control inflammation. Epigallocatechin gallate (EGCG) is a potent anti-inflammatory agent and an active ingredient of green tea and is suggested to have a role as a preventive agent in obesity, diabetes and CVD. The role of EGCG in the modulation of Tregs has, however, not been studied. Thus, the aim of the present study was to determine the effect of EGCG on the number and function of Tregs in obese and lean human subjects in vitro, and to delineate its specific regulation mechanisms. Tregs were isolated from normal-weight and obese subjects. Tregs were cultured in the absence or presence of EGCG (20 mum) for 24 h. Foxp3-expressing Tregs were enumerated using flow cytometry. Histone deacetylase (HDAC) activity and nuclear NF-kappaBp65 level were measured by ELISA and Western blots. Obese subjects had lower Tregs and IL-10 production than lean subjects. EGCG treatment significantly enhanced the number of Foxp3-expressing Tregs and IL-10 production in vitro (P < 0.05) in both groups. Also, EGCG decreased NF-kappaB activity and increased HDAC activity and HDAC-2 expression in Tregs (P < 0.05) in both groups. Thus, in part, EGCG enhances the functionality of Tregs, i.e. IL-10 production and number by suppressing the NF-kappaB signalling pathway via inducing epigenetic changes.
(n° 188) Epigallocatechin-3-gallate downregulates Pg-P and BCRP in a tamoxifen resistant MCF-7 cell line.
Farabegoli F, Papi A, Bartolini G, Ostan R, Orlandi M., Phytomedicine. 2010 Apr;17(5):356-62. Epub 2010 Feb 10, 14, University of Bologna, Bologna, Italy.
We investigated the anticancer effect of EGCG treatment on a breast carcinoma cell line resistant to tamoxifen (MCF-7Tam cells). In conclusion, the present results showed that EGCG could down-regulate the activity of two molecules that play a key role in drug metabolism and transport and that are highly expressed in tamoxifen resistant breast carcinoma cells. The interaction of EGCG and drugs used in the therapy of estrogen sensitive breast carcinoma ought to be subject of studies and the potential use of EGCG in drug-resistant diseases ought to be better considered.
(n° 189) Protective role of tannin-rich fraction of Camellia Sinensis in tissue arsenic burden in Sprague Dawley rats.
Chandronitha C, Ananthi S, Ramakrishnan G, Lakshmisundaram R, Gayathri V, Vasanthi HR., Hum Exp Toxicol. 2010 Sep;29(9):705-19. Epub 2010 Feb 9, Sri Ramachandra University, Chennai, India.
The protective effect of green tea (Camellia Sinensis) was tested against arsenic-induced toxicity. However, the possible role of tannins in green tea in alleviating hepatic and renal oxidative injury has also been studied. The protective role of tannin-rich fraction of C. Sinensis when compared to the detannified fraction was also confirmed by histological examinations. The greater activity of GTC than that of detannified green tea fraction correlates with the higher content of tannins in green tea. Overall, these results indicate that the tannin-rich green tea could have improved the defense mechanism against arsenic-induced oxidative stress and reduced the tissue arsenic burden.
(n° 190) Antimicrobial activities of tapioca starch/decolorized hsian-tsao leaf gum coatings containing green tea extracts in fruit-based salads, romaine hearts and pork slices.
Chiu PE, Lai LS., Int J Food Microbiol. 2010 Apr 30;139(1-2):23-30. Epub 2010 Jan 20, National Chung Hsing University, Kuo-Kuang Road, Taichung, 402, Taiwan, ROC.
The antimicrobial activities of edible coatings based on a tapioca starch/decolorized hsian-tsao leaf gum (dHG) matrix with various green tea extracts (GTEs) were evaluated. It was believed that the active compounds in green tea extracts could leave the coating matrix and migrate to increase the non-growth area. When being sprayed on various real food models, all tapioca starch/dHG coatings containing GTEs could successfully reduce the aerobic counting and growth of yeasts/molds by 1 to 2 log cycles in fruit-based salads, as compared to the control sample. Furthermore, during refrigerated storage of romaine hearts and pork slices for 48h, tapioca starch/dHG coatings with E4 extracts demonstrated pronounced antimicrobial activity against Gram positive bacteria (4-6 log cycles reduction), followed by W extracts and E8 extracts in a decreasing order. Such results implied the high efficacy of antimicrobial migration of tapioca starch/dHG coatings containing GTEs and their application potentials on foods.
(n° 191) Dietary green tea extract increases phase 2 enzyme activities in protecting against myocardial ischemia-reperfusion.
Akhlaghi M, Bandy B., Nutr Res. 2010 Jan;30(1):32-9, Shiraz University of Medical Sciences, Shiraz, Iran.
Green tea catechins are dietary antioxidant compounds that have been shown to protect against myocardial ischemia-reperfusion (IR) injury. Considering reports that catechins can induce phase 2 enzymes in cultured cells and some organs, we hypothesized that part of the protection to heart against IR injury may involve elevation of phase 2 enzyme activities. The results support a possible involvement of phase 2 enzymes in the protection by green tea catechins against myocardial IR injury.
(n° 192) Addition of whole, semiskimmed, and skimmed bovine milk reduces the total antioxidant capacity of black tea.
Ryan L, Petit S., Nutr Res. 2010 Jan;30(1):14-20, Oxford Brookes University, Oxford, United Kingdom.
Epidemiological studies have shown that populations consuming fruits, vegetables, tea, cocoa, and red wine have lower incidences of cardiovascular disease, certain cancers, and eye disease. These health effects have largely been attributed to the polyphenol content of the foods and drinks studied. Black tea is rich in a range of polyphenolic compounds that could potentially have health-promoting properties. We conclude that black tea is a valuable source of antioxidants and that the effect of milk on the total antioxidant capacity may be related to the fat content of the milk.
(n° 193) The antioxidant effect of green tea catechin ameliorates experimental liver injury.
Kobayashi H, Tanaka Y, Asagiri K, Asakawa T, Tanikawa K, Kage M, Yagi M., Phytomedicine. 2010 Sep;17(11):910. Epub 2010 Jan 25, Kurume University School of Medicine, Asahimachi, Kurume-city, Fukuoka, Japan.
Several studies have reported green tea catechin to have both antifibrotic and anti-oxidative effects. The goal of this study was to evaluate the effect of green tea cathechin therapy in hepatic tissue injury using cholestatic rats with bile duct ligation. Green tea catechin may reduce hepatic fibrosis by suppressing oxidative stress and controlling the transcription factor expression involved in stellate cell activation.
(n° 194) Laboratory, epidemiological, and human intervention studies show that tea (Camellia Sinensis) may be useful in the prevention of obesity.
Grove KA, Lambert JD., J Nutr. 2010 Mar;140(3):446-53. Epub 2010 Jan 20, The Pennsylvania State University, University Park, PA, USA.
Tea (Camellia Sinensis, Theaceae) and tea polyphenols have been studied for the prevention of chronic diseases, including obesity. In this review, we will critically evaluate the evidence for the prevention of obesity by tea, discuss the relevance of proposed mechanisms in light of tea polyphenol bioavailability, and review the reports concerning the toxic effects of high doses of tea polyphenols and the implication that this has for the potential use of tea for the prevention of obesity. We hope that this review will expose areas for further study and encourage research on this important public health issue.
(n° 195) Green tea ameliorates renal oxidative damage induced by gentamicin in rats.
Abdel-Raheem IT, El-Sherbiny GA, Taye A., Pak J Pharm Sci. 2010 Jan;23(1):21-8, AL-Azhar University, Assiut, Egypt.
Recent studies indicate that free radicals are important mediators of renal damage induced by gentamicin (GM), an aminoglycoside antibiotic widely used in treating severe gram-negative infections. Green tea extract (GTE) was reported to have antioxidant and free radical scavenging activities. GM produced elevation in urinary total protein, BUN, serum creatinine and TBARS levels. On the other hand, GM reduced the GSH level and SOD, CAT activities. The simultaneous administration of GTE plus gentamicin protected kidney tissues against nephrotoxic effect of gentamicin as evidenced from amelioration of histopathological alterations and normalization of kidney biochemical parameters.
(n° 196) Green tea averts age-dependent decline of hippocampal signaling systems related to antioxidant defenses and survival.
Assunção M, Santos-Marques MJ, Carvalho F, Andrade JP., Free Radic Biol Med. 2010 Mar 15;48(6):831-8. Epub 2010 Jan 11, University of Porto, Porto, Portugal.
We previously found that prolonged consumption of green tea (GT), a rich source of antioxidant polyphenols, protected proteins and lipids against oxidation and reduced lipofuscin deposition in the rat hippocampal formation as well as improving spatial memory during aging. We conclude that long-term GT ingestion improves antioxidant systems and activates CREB in the aging rat hippocampal formation, leading to neuroprotection mediated by downstream upregulation of BDNF and Bcl-2.
(n° 197) Preventive effect of green tea catechins on experimental tumor metastasis in senescence-accelerated mice.
Shimizu K, Kinouchi Shimizu N, Hakamata W, Unno K, Asai T, Oku N., Biol Pharm Bull. 2010 Jan;33(1):117-21, University of Shizuoka, Shizuoka, Japan.
Successful avoidance of the immune surveillance system is critical for the development of a blood-borne metastasis. The results suggest that GT-catechin intake prevented the experimental tumor metastasis in aged SAMP10 mice via its inhibition of a reduction in immune surveillance potential with age.
(n° 198) The inhibitory effect of Camellia Sinensis extracts against the neuromuscular blockade of Crotalus durissus terrificus venom.
de Jesus Reis Rosa L, Silva GA, Filho JA, Silva MG, Cogo JC, Groppo FC, Oshima-Franco Y., J Venom Res. 2010 Sep 30;1:1-7.
In geographically isolated populations where intensive medical care or serum therapy is not easily accessible snake envenomation is a major cause for concern. The aim of the present study was to test Camellia Sinensis extracts, theaflavin and epigallocatechin (two of the main C. Sinensis components) against the irreversible neuromuscular blockade induced by Crotalus durissus terrificus venom in mouse phrenic-nerve diaphragm preparations. The histological data confirms that Cs is able to protect the muscle from the myotoxic activity of the venom. Commercial epigallocatechin gallate did not show pre-synaptic nor post-synaptic activities. C. Sinensis extract was able to protect the mouse phrenic-nerve diaphragm against the irreversible neuromuscular blockade induced by C. durissus terrificus venom.
(n° 199) Inhibitory effects of (-)-epigallocatechin-3-gallate from green tea on the growth of Babesia parasites.
Aboulaila M, Yokoyama N, Igarashi I., Parasitology. 2010 Apr;137(5):785-91. Epub 2009 Dec 22, Obihiro University of Agriculture and Veterinary Medicine, Inada-Cho, Obihiro, Hokkaido, Japan.
(-)-Epigallocatechin-3-gallate (EGCG) is the major tea catechin and accounts for 50-80% of the total catechin in green tea. (-)-Epigallocatechin-3-gallate has antioxidant, anti-inflammatory, anti-microbial, anti-cancer, and anti-trypanocidal activities. This report describes the inhibitory effect of (-)-Epigallocatechin-3-gallate on the in vitro growth of bovine Babesia parasites and the in vivo growth of the mouse-adapted rodent babesia B. microti. The drug significantly (P<0.05) inhibited the growth of B. microti at doses of 5 and 10 mg/kg body weight, and the parasites completely cleared on day 14 and 16 post-inoculation in the 5 and 10 mg/kg treated groups, respectively. These findings highlight the potentiality of (-)-Epigallocatechin-3-gallate as a chemotherapeutic drug for the treatment of babesiosis.
(n° 200) Association between green tea intake and coronary artery disease in a Chinese population.
Wang QM, Gong QY, Yan JJ, Zhu J, Tang JJ, Wang MW, Yang ZJ, Wang LS., Circ J. 2010 Feb;74(2):294-300. Epub 2009 Dec 17, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China.
There is still conflicting evidence that green tea may protect against coronary atherosclerosis therefore the present study investigated the association between green tea consumption and arteriographically determined coronary atherosclerosis in a Chinese population. Green tea consumption can protect against the development of coronary atherosclerosis in Chinese male patients.
(n° 201) Antiangiogenic properties of a nutrient mixture in a model of hemangioma.
Roomi MW, Kalinovsky T, Niedzwiecki A, Rath M., Exp Oncol. 2009 Dec;31(4):214-9, Dr. Rath Research Institute, Oncology Division, Santa Clara, CA, USA.
The pathogenesis of hemangiomas is still largely unknown and the current therapy, such as systemic corticosteroid, vincristine, and interferon-alpha, is toxic and remains unsatisfactory. A nutrient mixture (NM) containing lysine, proline, ascorbic acid and green tea extract has shown significant anti-angiogenic and anti-tumor effect against a number of cancer cell lines. Aim: Using a mouse hemangioendothelioma model, we investigated the efficacy of NM. We also tested the effect of NM in vitro, evaluating cell viability, MMP secretion, invasion, morphology and apoptosis. NM inhibited the growth of tumors by 50%. In vitro, NM exhibited dose response cytotoxicity with 10%, 30% and 55% at 10, 100 and 1000 microg/ml. Invasion through Matrigel was inhibited at 50, 100 and 500 microg/ml by 25%, 30% and 100% respectively. NM induced dose-dependent apoptosis of EOMA cells. These results suggest that NM may have therapeutic potential in treating infantile hemangioendotheliomas and, perhaps, other cutaneous vascular tumors.
(n° 202) A pilot study of the role of green tea use on oral health.
Awadalla HI, Ragab MH, Bassuoni MW, Fayed MT, Abbas MO., Int J Dent Hyg. 2011 May;9(2):110-6. doi: 10.1111/j.1601-5037.2009.00440.x, Ain Shams University, Cairo, Egypt.
An increasing number of people all around the world are turning to the nature by using the natural herbal products in both prophylaxes and treatment of different diseases. Green tea with active chemical ingredients posses diverse pharmacological properties that include anti-inflammatory, anticariogenic, antioxidant and antibacterial effects. The results of this study showed that there was a statistically significant difference among subjects pre- and post-rinsing with 2% green tea for 5 min concerning S. mutans count in saliva and plaque, salivary and plaque pH values and GBI. This study supports the effectiveness of local application of green tea as antibacterial and anticariogenic material as it decreases the acidity of the saliva and plaque, so it is a cost-effective caries prevention measures especially in developing countries.
(n° 203) Green tea polyphenols for prostate cancer chemoprevention: a translational perspective.
Johnson JJ, Bailey HH, Mukhtar H., Phytomedicine. 2010 Jan;17(1):3-13, University of Wisconsin School of Pharmacy, Madison, WI, USA.
Every year nearly 200,000 men in the United States are diagnosed with prostate cancer (PCa), and another 29,000 men succumb to the disease. Within certain regions of the world population based studies have identified a possible role for green tea in the prevention of certain cancers, especially PCa. One constituent in particular, epigallocatechin-3-gallate also known as EGCG has been shown in cell culture models to decrease cell viability and promote apoptosis in multiple cancer cell lines including PCa with no effect on non-cancerous cell lines. This review will present the available data for standardized green tea polyphenols in regard to PCa chemoprevention that will include epidemiological, mechanism based studies, safety, pharmacokinetics, and applicable clinical trials. The data that has been collected so far suggests that green tea may be a promising agent for PCa chemoprevention and further clinical trials of participants at risk of PCa or early stage PCa are warranted.
(n° 204) Inhibition property of green tea extract in relation to reserpine-induced ribosomal strips of rough endoplasmic reticulum (rER) of the rat kidney proximal tubule cells.
Abdel-Majeed S, Mohammad A, Shaima AB, Mohammad R, Mousa SA., J Toxicol Sci. 2009 Dec;34(6):637-45, Kuwait University, Kuwait.
The aim of this study was to evaluate the effect of green tea in inhibiting and reversing the nephrotoxicity of reserpine--a potent oxidative stress inducer--which induced cellular kidney damage. Sixty rats were randomly divided into six groups, with 10 rats in each group. Reserpine was found to cause kidney proximal tubule damage, such as stripping and clustering of ribosomes from the rough endoplasmic reticulum (rER) and demolishing of mitochondrial christae with elevated level of oxidative stress markers, such as TBARS. While the ultrastructural study showed a revival of kidney proximal tubule cells as a result of the administration of green tea extract to rats. We suggest that green tea might elevate antioxidant defense system, clean up free radicals, lessen oxidative damages and protect kidney against reserpine-induced toxicity and thus had a potential protective effect.
(n° 205) Inhibitory effects of tea polyphenols by targeting cyclooxygenase-2 through regulation of nuclear factor kappa B, Akt and p53 in rat mammary tumors.
Roy P, George J, Srivastava S, Tyagi S, Shukla Y., Invest New Drugs. 2011 Apr;29(2):225-31. Epub 2009 Nov 20, Indian Institute of Toxicology Research, CSIR, Mahatma Gandhi Marg, Lucknow, India.
Breast cancer has become the second leading cause of cancer-related deaths worldwide. The control of this disease can be achieved through chemoprevention, which refers to the consumption of synthetic or naturally occurring agents to block, reverse, or delay the process of tumor development. Tea (Camellia Sinensis), the most widely consumed beverage, has shown promises in the field of cancer chemoprevention. Inhibition of tumorigenesis by green or black tea polyphenols has been demonstrated in various in vitro and in vivo models. Altogether, the study suggests that both cultivars of tea, i.e. green and black, have anti-tumorigenic potential against DMBA-induced mammary tumorigenesis in Wistar rats. Further studies such as large and long term cohort studies and clinical trials are warranted.
(n° 206) Green tea, black tea, and epigallocatechin modify body composition, improve glucose tolerance, and differentially alter metabolic gene expression in rats fed a high-fat diet.
Chen N, Bezzina R, Hinch E, Lewandowski PA, Cameron-Smith D, Mathai ML, Jois M, Sinclair AJ, Begg DP, Wark JD, Weisinger HS, Weisinger RS., Nutr Res. 2009 Nov;29(11):784-93, University of Melbourne, Australia.
The mechanisms of how tea and epigallocatechin-3-gallate (EGCG) lower body fat are not completely understood. This study investigated long-term administration of green tea (GT), black tea (BT), or isolated EGCG (1 mg/kg per day) on body composition, glucose tolerance, and gene expression related to energy metabolism and lipid homeostasis; it was hypothesized that all treatments would improve the indicators of metabolic syndrome. The results suggest that GT and BT suppressed adipocyte differentiation and fatty acid uptake into adipose tissue, while increasing fat synthesis and oxidation by the liver, without inducing hepatic fat accumulation. In contrast, EGCG increased markers of thermogenesis and differentiation in adipose tissue, while having no effect on liver or muscle tissues at this dose. These results show novel and separate mechanisms by which tea and EGCG may improve glucose tolerance and support a role for these compounds in obesity prevention.
(n° 207) Effect of green tea extract (catechins) in reducing oxidative stress seen in patients of pulmonary tuberculosis on DOTS Cat I regimen.
Agarwal A, Prasad R, Jain A., Phytomedicine. 2010 Jan;17(1):23-7. Epub 2009 Nov 11, Chhatrapati Shahuji Maharaj Medical University, Lucknow, UP, India.
The role played by free radicals in pathogenesis of pulmonary tuberculosis and treatment mediated toxicity is well established. Hence, the present study was undertaken to assess the effect of crude green tea catechin in reducing the oxidative stress seen in patients of AFB positive pulmonary tuberculosis. The results showed significant difference in all the parameters among cases and controls. A significant decrease (p< or = 0.001) in LPO level was observed in cases as compare to controls during the follow up while the level of NO was significantly increased (p< or =0.001) in cases as compare to controls. Significant decrease (p< or =0.001) in catalase and GPx level was observed in cases as compare to controls while SOD levels significantly rose (p< or =0.001) in cases as compared to controls. Significant decrease (p< or =0.001) in SH level was observed in cases as compared to controls while the level of GSH was significantly increased (p< or =0.001) . These findings suggest that crude catechin extract can play a definite role as adjuvant therapy in management of oxidative stress seen in pulmonary tuberculosis patients. More detailed studies are needed to document use of catechin in reducing the frequency and severity of side effects of treatment.
(n° 208) Tea catechins' affinity for human cannabinoid receptors.
Korte G, Dreiseitel A, Schreier P, Oehme A, Locher S, Geiger S, Heilmann J, Sand PG., University of Regensburg, Regensburg, Germany.
Among the many known health benefits of tea catechins count anti-inflammatory and neuroprotective activities, as well as effects on the regulation of food intake. Here we address cannabimimetic bioactivity of catechin derivatives occurring in tea leaves as a possible cellular effector of these functionalities. It can be concluded that central nervous cannabinoid receptors may be targeted by selected tea catechins but signaling via peripheral type receptors is less likely to play a major role in vivo.
(n° 209) Tea, coffee, and cocoa as ultraviolet radiation protectants for the beet armyworm nucleopolyhedrovirus.
El-Salamouny S, Ranwala D, Shapiro M, Shepard BM, Farrar RR Jr., J Econ Entomol. 2009 Oct;102(5):1767-73, Clemson University Coastal Research & Education Center, Charleston, USA.
The addition of 1% (wt:vol) aqueous extracts of cocoa (Theobroma cacao L.) (Malvales: Malvaceae), coffee (Coffea arabica L.) (Gentianales: Rubiaceae), and green and black tea (Camellia Sinensis L.) This study demonstrated that coffee was comparable to green tea and black tea as a UV protectant. Further studies should be conducted to optimize their use in biopesticide formulations.
(N° 210) Sorption of lead from aqueous solutions by tea wastes.
Liu N, Lin D, Lu H, Xu Y, Wu M, Luo J, Xing B., J Environ Qual. 2009 Oct 29;38(6):2260-6. Print 2009 Nov-Dec, Zhejiang University, Hangzhou 310028, China.
Environmental contamination by heavy metals has long been a worldwide concern. Tea wastes, having porous surfaces with polar functional groups, could be a good sorbent for removal of Pb(II) from wastewaters. This study aimed to investigate the potential of tea wastes as a sorbent for removal of Pb(II) from solution and the underlying sorption mechanism. Tea wastes showed high removal efficiency for Pb(II) with a short equilibration time and high sorption capacity. The sorptive affinity increased with increasing solution pH and leveled off at about pH 5. Higher temperature led to a higher sorptive affinity, indicating the sorption being an endothermic process. Coexisting metal ions lowered the sorption of Pb(II) with an order of Ag(I)<Cu(II)<Al(III). Fourier transform infrared (FTIR) spectrometer and scanning electron microscopy (SEM) with an X-ray energy dispersion spectroscopy (EDS) accessory were used to examine the underlying mechanism of the Pb(II) sorption. Surface complex formation with carboxylic and amine groups and ion exchanges were observed to regulate the binding of Pb(II) to the tea wastes.
(n° 211) Protective effect of royal jelly and green tea extracts effect against cisplatin-induced nephrotoxicity in mice: a comparative study.
Yapar K, Cavuşoğlu K, Oruç E, Yalçin E., J Med Food. 2009 Oct;12(5):1136-42, Giresun University, Giresun, Turkey.
The aim of the present study was to investigate the protective role of royal jelly (RJ) and green tea (GT) extracts on cisplatin (cDDP)-induced nephrotoxicity in adult albino mice. The results indicated that no significant differences in MDA, GSH, BUN, and creatinine levels were observed among the control group and groups treated with RJ alone and GT alone (P > .05). However, there was a significant increase in BUN and creatinine parameters after cDDP application in Groups II, V, and VI. The mice treated with only cDDP exhibited an increase in serum BUN and creatinine levels when compared to Groups V and VI (P < .05). Moreover, cDDP-induced oxidative damage caused a significant decrease in GSH levels and a significant increase in MDA levels in kidneys (P < .05). RJ and GT supplementation attenuated cDDP-induced nephrotoxicity, which was manifested by stopping the elevation in serum creatinine and BUN levels. Moreover, RJ and GT supplementation restored GSH content and MDA production levels in the kidney tissue following cDDP treatment (P < .05). These products were also effective in protecting against cDDP-induced tissue damage in mouse kidneys. In conclusion, 100 mg/kg of body weight doses of RJ and GT provided protection against cDDP-induced nephrotoxicity, and both products can act as protector agents against cDDP-induced kidney damages.
(n° 212) Chemopreventive effect of a novel nutrient mixture on lung tumorigenesis induced by urethane in male A/J mice.
Roomi MW, Roomi NW, Kalinovsky T, Rath M, Niedzwiecki A., Tumori. 2009 Jul-Aug;95(4):508-13, Dr Rath Research Institute, Santa Clara, CA, USA.
Lung cancer, a leading cause of cancer death, is associated with exposure to inhalation carcinogens, most commonly those found in tobacco smoke. We investigated the in vivo effect of dietary supplementation with a nutrient mixture containing lysine, proline, arginine, ascorbic acid, green tea extract, N-acetyl cysteine, selenium, copper and manganese on the development of urethane-induced lung tumors in male A/J mice. Urethane-challenged mice developed tumors. However, the mean number of tumors and the mean lung weights in the mice on the supplemented diet were significantly reduced, by 49% (P < 0.0001) and 18% (P = 0.0025), respectively, compared to mice on the control diet. We observed neither significant differences in body weight gains nor in diet consumption among the mice. Pulmonary lesions were morphologically similar for both the groups (adenomas), but lesions were smaller in the test group. The results suggest that nutrient mixture has inhibitory potential on the development of mouse lung tumors induced by urethane.
(n° 213) Tea catechins inhibit hepatocyte growth factor receptor (MET kinase) activity in human colon cancer cells: kinetic and molecular docking studies.
Larsen CA, Bisson WH, Dashwood RH., J Med Chem. 2009 Nov 12;52(21):6543-5, Oregon State University, Corvallis, Oregon, USA.
Most cancer deaths result from spread of the primary tumor to distant sites (metastasis). MET is an important protein for metastasis in multiple tumor types. Here we report on the ability of tea catechins to suppress MET activation in human colon cancer cells and propose a mechanism by which they might compete for the kinase domain of the MET protein.
(n° 214) Effects of 3-week consumption of green tea extracts on whole-body metabolism during cycling exercise in endurance-trained men.
Eichenberger P, Colombani PC, Mettler S., Int J Vitam Nutr Res. 2009 Jan;79(1):24-33, Institute of Human Movement Sciences and Sport, ETH Zurich, Switzerland.
The consumption of green tea has been generally associated with beneficial effects on human whole-body metabolism and recent investigations with animals indicate favorable effects of green tea extracts (GTE) on energy metabolism during exercise and aerobic exercise performance. Therefore, the purpose of this study was to examine the effects of a three-week supplementation with GTE on human energy metabolism during submaximal cycling exercise. The GTE supplementation did not influence indices of fat and energy metabolism (fatty acids, 3-beta-hydroxybutyrate, triacylglycerol, low-density-lipoprotein cholesterol, total cholesterol, lactate, glucose, oxygen uptake, respiratory exchange ratio, energy expenditure), inflammation processes (interleukin-6, C-reactive protein), and oxidative stress (thiobarbituric-acid reactive substances, oxidized low-density-lipoprotein cholesterol), but plasma creatine kinase concentration at rest and during exercise was significantly lower (p = 0.039) and high-density-lipoprotein cholesterol concentration at rest was significantly higher (p = 0.043) compared to placebo. In conclusion, these results suggest only slight effects on whole-body metabolism after supplementation with GTE.
(n° 215) Prospective double-blind crossover study of Camellia Sinensis (green tea) in dyslipidemias.
Batista Gde A, Cunha CL, Scartezini M, von der Heyde R, Bitencourt MG, Melo SF., Arq Bras Cardiol. 2009 Aug;93(2):128-34, Universidade Federal do Paraná, PR, Brasil.
Epidemiological studies have established an association between dyslipidemias and atherosclerosis. Nutritional therapy is a key point in the prevention strategy for individuals who present with risk factors for atherosclerotic disease. Baseline lipid values (mg/dL) were: HDL-cholesterol 60.7 +/- 7.3; total cholesterol 255 +/- 30.9; LDL-cholesterol 158.8 +/- 29.0; triglycerides 169.0 +/- 61.3 and Apo-B 120.2 +/- 18.9. Mean lipid variations induced by the use of green tea (Camellia Sinensis) showed a 3.9% reduction (p = 0.006) in total cholesterol concentrations and a 4.5% reduction (p = 0.026) in LDL-cholesterol. The intake of green tea did not significantly influence HDL-cholesterol, triglyceride, and Apo-B levels. Non-significant results were found in the assessment of blood lipids (total cholesterol and LDL-cholesterol) with the use of placebo. A beneficial effect of green tea (Camellia Sinensis) was demonstrated, with a significant reduction of total cholesterol and LDL-cholesterol levels in eight weeks, in the patients studied.
(n° 216) The effects of polyphenol-containing antioxidants on oxidative stress and lipid peroxidation in Type 2 diabetes mellitus without complications.
Fenercioglu AK, Saler T, Genc E, Sabuncu H, Altuntas Y., J Endocrinol Invest. 2010 Feb;33(2):118-24. Epub 2009 Oct 15, Yeditepe University Medical Faculty, Istanbul, Turkey.
The hyperglycemia-induced oxidative stress in diabetes mellitus (DM) is the major factor in the pathogenesis of cardiovascular complications. The phenolic compounds are potent antioxidants that can reverse the factors leading to cardiovascular complications in DM. The aim of this study was to determine the antagonizing effects of a polyphenol-rich antioxidant supplement containing pomegranate extract, green tea extract, and ascorbic acid, on oxidative stress in Type 2 diabetic patients. The study group showed a decrease in LDL and an increase in HDL and the comparison with the difference in placebo group was statistically significant (p<0.001 for LDL and p<0.001 for HDL). Accordingly, as a by-product of lipid peroxidation, plasma MDA was decreased in the study group compared to the placebo group (p<0.001). As an indicator of increased antioxidant defense, total plasma GSH and AOC increased more in the study group compared to control group (p<0.001). These observations indicated that the polyphenol-rich antioxidant supplement containing pomegranate extract, green tea extract, and ascorbic acid has important antagonizing effects on oxidative stress and lipid peroxidation in patients with Type 2 DM and might be beneficial in preventing cardiovascular complications.
(n° 218) Green tea extracts lower serum folates in rats at very high dietary concentrations only and do not affect plasma folates in a human pilot study.
Augustin K, Frank J, Augustin S, Langguth P, Ohrvik V, Witthoft CM, Rimbach G, Wolffram S., J Physiol Pharmacol. 2009 Sep;60(3):103-8, Christian Albrechts University, Kiel, Germany.
Green tea catechins (GTC) have been shown to inhibit the activities of enzymes involved in folate uptake. Hence, regular green tea drinkers may be at risk of impaired folate status. The present experiments aimed at studying the impact of dietary GTC on folate concentrations and metabolism. Using an in vitro enzyme activity assay, we observed a time- and dose-dependent inhibition of DHFR activity by epigallocatechin gallate and a green tea extract. Our data suggest that regular green tea consumption is unlikely to impair folate status in healthy males, despite the DHFR inhibitory activity of GTC.
(n° 219) Antiproliferative and proapoptotic effects of epigallocatechin gallate on human leiomyoma cells.
Zhang D, Al-Hendy M, Richard-Davis G, Montgomery-Rice V, Rajaratnam V, Al-Hendy A., Fertil Steril. 2010 Oct;94(5):1887-93. Epub 2009 Oct 12, Meharry Medical College, Nashville, Tennessee, USA.
The HuLM cells treated with EGCG showed a dose-dependent and time-dependent inhibition of cell proliferation. The TUNEL staining indicated a significant increase in apoptosis in HuLM cells treated with 100 μM of EGCG compared with untreated control. Gene expression profiling indicated that EGCG treatment up-regulated representative genes from the transforming growth factor β (TGF-β) and stress pathways, while inhibiting the survival pathway and NFκB-dependent inflammatory pathway. Western blot analysis confirmed that EGCG at ≥50 μM significantly decreased the expression of PCNA, CDK4, and BCL2 as well as increased the expression of the proapoptotic BAX in a dose-dependent manner. Epigallocatechin gallate inhibits the proliferation of HuLM cells and induces apoptosis. These results suggest that EGCG may be a potential anti-uterine fibroid agent acting through multiple signal transduction pathways.
(n° 220) Skin penetration of epigallocatechin-3-gallate and quercetin from green tea and Ginkgo biloba extracts vehiculated in cosmetic formulations.
dal Belo SE, Gaspar LR, Maia Campos PM, Marty JP., Skin Pharmacol Physiol. 2009;22(6):299-304. Epub 2009 Sep 25, University of São Paulo, São Paulo, Brazil.
Green tea (Camellia Sinensis) and Ginkgo biloba extracts in cosmetic formulations have been suggested to protect the skin against UV-induced damage and skin ageing. Thus, it is very important to assess the human skin penetration of their major flavonoids to verify if they penetrate and remain in the skin to exert their proposed effects. The results showed that the flavonoids under study penetrated into the skin, without reaching the receptor fluid. The majority of EGCG was quantified in the stratum corneum (0.87 microg/cm(2)), which was statistically higher than the EGCG concentrations found in viable epidermis (0.54 microg/cm(2)) and in the dermis (0.38 microg/cm(2)). The majority of quercetin was quantified in the viable epidermis (0.23 microg/cm(2)), which was statistically higher than the EGCG concentration found in the stratum corneum layer (0.17 microg/cm(2)). Finally, it can be concluded that EGCG and quercetin from green tea and G. biloba extracts vehiculated in cosmetic formulations presented good skin penetration and retention, which can favor their skin effects.
(n° 221) Influence of green tea on erythrocytes antioxidant status of different age rats intoxicated with ethanol.
Wojciech Ł, Ewa Z, Elzbieta S., Phytother Res. 2010 Mar;24(3):424-8, Medical University of Bialystok, Bialystok, Poland.
The aim of this paper is to evaluate the effect of green tea on the erythrocyte antioxidant system of ethanol-intoxicated rats, as well as its efficacy in the prevention of lipid peroxidation It was shown that ageing was accompanied by changes in the antioxidant enzymes activity - increase in the SOD and CAT activity and decrease in GSSG-R and GSH-Px activity, as well as in the level of non-enzymatic antioxidants - GSH, vitamin A and vitamin E. The increase in the level of lipid peroxidation marker - MDA - was also observed. Green tea consumption partially prevented lipid peroxidation process, especially in erythrocytes of 2- and 12-month-old rats. It was proved that ethanol administration caused a statistically significant decrease in the activity/level of the examined antioxidants in all age groups (the most significant in the case of 24-month-old rats) of rats, as well as an increase in the MDA level. However, ingestion of green tea by ethanol-intoxicated rats partially prevented the decrease in activity/level of all examined antioxidant parameters, as well as protected lipids against peroxidation in all age groups of rats. Obtained results confirm the beneficial effect of green tea on erythrocyte antioxidant abilities.
(n° 222) L-Theanine, an amino acid in green tea, attenuates beta-amyloid-induced cognitive dysfunction and neurotoxicity: reduction in oxidative damage and inactivation of ERK/p38 kinase and NF-kappaB pathways.
Kim TI, Lee YK, Park SG, Choi IS, Ban JO, Park HK, Nam SY, Yun YW, Han SB, Oh KW, Hong JT., Free Radic Biol Med. 2009 Dec 1;47(11):1601-10. Epub 2009 Sep 16, Chungbuk National University, Cheongju, Chungbuk, Korea.
Amyloid beta (Abeta)-induced neurotoxicity is a major pathological mechanism of Alzheimer disease (AD). In this study, we investigated the inhibitory effect of l-theanine, a component of green tea (Camellia Sinensis), on Abeta(1-42)-induced neuronal cell death and memory impairment. Oral treatment of l-theanine (2 and 4 mg/kg) for 5 weeks in the drinking water of mice, followed by injection of Abeta(1-42) (2 microg/mouse, icv), significantly attenuated Abeta(1-42)-induced memory impairment. Furthermore, l-theanine reduced Abeta(1-42) levels and the accompanying Abeta(1-42)-induced neuronal cell death in the cortex and hippocampus of the brain. Moreover, l-theanine inhibited Abeta(1-42)-induced extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase as well as the activity of nuclear factor kappaB (NF-kappaB). l-Theanine also significantly reduced oxidative protein and lipid damage and the elevation of glutathione levels in the brain. These data suggest that the positive effects of l-theanine on memory may be mediated by suppression of ERK/p38 and NF-kappaB as well as the reduction of macromolecular oxidative damage. Thus, l-theanine may be useful in the prevention and treatment of AD.
(n° 223) Green tea (Camellia Sinensis) catechins and vascular function.
Moore RJ, Jackson KG, Minihane AM., Br J Nutr. 2009 Dec;102(12):1790-802, University of Reading, Whiteknights, Reading, UK.
The health benefits of green tea (Camellia Sinensis) catechins are becoming increasingly recognised. Amongst the proposed benefits are the maintenance of endothelial function and vascular homeostasis and an associated reduction in atherogenesis and CVD risk. The mounting evidence for the influential effect of green tea catechins on vascular function from epidemiological, human intervention and animal studies is subject to review together with exploration of the potential mechanistic pathways involved. Epigallocatechin-3-gallate, one of the most abundant and widely studied catechin found in green tea, will be prominent in the present review. Since there is a substantial inconsistency in the published data with regards to the impact of green tea catechins on vascular function, evaluation and interpretation of the inter- and intra-study variability is included. In conclusion, a positive effect of green tea catechins on vascular function is becoming apparent. Further studies in animal and cell models using physiological concentrations of catechins and their metabolites are warranted in order to gain some insight into the physiology and molecular basis of the observed beneficial effects.
(n° 224) Matcha, a powdered green tea, ameliorates the progression of renal and hepatic damage in type 2 diabetic OLETF rats.
Yamabe N, Kang KS, Hur JM, Yokozawa T., J Med Food. 2009 Aug;12(4):714-21, University of Toyama, Toyama, Japan.
Matcha, a powdered green tea produced by grinding with a stone mill, has been popularly used in the traditional tea ceremony and foods in Japan. Matcha is well known to be richer in some nutritional elements and epigallocatechin 3-O-gallate than other green teas. OLETF rats were orally administered Matcha for 16 weeks, and we assessed biochemical parameters in the serum, liver, and kidney and expression levels of major products of advanced glycation end products (AGEs), N(6)-(carboxylmethyl)lysine (CML) and N(6)-(carboxylethyl)lysine (CEL), receptor for AGE (RAGE), and sterol regulatory element binding proteins (SREBPs)-1 and -2. Serum total protein levels were significantly increased by Matcha administration, whereas the serum albumin and glycosylated protein levels as well as the renal glucose and triglyceride levels were only slightly or not at all affected. However, Matcha treatment significantly lowered the glucose, triglyceride, and total cholesterol levels in the serum and liver, renal AGE levels, and the serum thiobarbituric acid-reactive substances levels. In addition, Matcha supplementation resulted in decreases in the renal CML, CEL, and RAGE expressions as well as an increase in hepatic SREBP-2 expression, but not that of SREBP-1. These results suggest that Matcha protects against hepatic and renal damage through the suppression of renal AGE accumulation, by decreases in hepatic glucose, triglyceride, and total cholesterol levels, and by its antioxidant activities.
(n° 225) Chlorhexidine and green tea extract reduce dentin erosion and abrasion in situ.
Magalhães AC, Wiegand A, Rios D, Hannas A, Attin T, Buzalaf MA., J Dent. 2009 Dec;37(12):994-8. Epub 2009 Sep 3, University of São Paulo, Bauru, SP, Brazil.
This in situ/ex vivo study aimed to analyse the impact of possible MMP-inhibitors (chlorhexidine and green tea extract) on dentin wear induced by erosion or erosion plus abrasion. There was a significant difference between the conditions (EroxEro+Abr, p<0.001) and among the solutions (p<0.001). All solutions (F: 1.42+/-0.34; 1.73+/-0.50, chlorhexidine: 1.15+/-0.26; 1.59+/-0.32, green tea: 1.06+/-0.30; 1.54+/-0.55) significantly reduced the dentin wear when compared to control (2.00+/-0.55; 2.41+/-0.83) for both conditions. There were not significant differences among green tea extract, chlorhexidine and F solutions. Thus, the possible MMP-inhibitors tested in this study seem to be a promising preventive measure to reduce dentin erosion-abrasion, but their mechanism of action needs to be investigated in further studies.
(n° 226) Black-tea polyphenols suppress postprandial hypertriacylglycerolemia by suppressing lymphatic transport of dietary fat in rats.
Kobayashi M, Ichitani M, Suzuki Y, Unno T, Sugawara T, Yamahira T, Kato M, Takihara T, Sagesaka Y, Kakuda T, Ikeda I., J Agric Food Chem. 2009 Aug 12;57(15):7131-6, Central Research Institute, ITO EN, Ltd., Shizuoka, Japan.
Administration of black-tea polyphenols (BTP) at 100 and 200 mg/kg of body weight in rats suppressed postprandial hypertriacylglycerolemia in a dose-dependent manner. Administration of BTP also suppressed lymphatic recovery of (14)C-trioleoylglycerol in rats that were cannulated in the thoracic duct. BTP dose-dependently inhibited the activity of pancreatic lipase in vitro with an IC50 of 0.254 mg/mL. When purified theaflavins, which are components of BTP, were used, theaflavins with galloyl moieties, but not those without galloyl moiety, inhibited the activity of pancreatic lipase. Theaflavin-3,3'-digallate (TFDG) was more effective in inhibiting the activity of pancreatic lipase than epigallocatechin gallate (EGCG), epicatechin gallate (ECG), and a mixture of EGCG and ECG. BTP and TFDG had a similar effect in inhibiting the activity of pancreatic lipase when the total polyphenol amount was adjusted to the same. BTP had no effect on micellar solubility of hydrolysis products of triacylglycerol. These results suggest that BTP suppressed postprandial hypertriacylglyce-rolemia by reducing triacylglycerol absorption via the inhibition of pancreatic lipase activity.
(n° 227) Green tea and bone metabolism.
Shen CL, Yeh JK, Cao JJ, Wang JS., Nutr Res. 2009 Sep;29(9):684., Texas Tech University Health Sciences Center, Lubbock, TX, USA.
Osteoporosis is a major health problem in both elderly women and men. Epidemiological evidence has shown an association between tea consumption and the prevention of age-related bone loss in elderly women and men. Ingestion of green tea and green tea bioactive compounds may be beneficial in mitigating bone loss of this population and decreasing their risk of osteoporotic fractures. This review describes the effect of green tea or its bioactive components on bone health, with an emphasis on (i) the prevalence and etiology of osteoporosis; (ii) the role of oxidative stress and antioxidants in osteoporosis; (iii) green tea composition and bioavailability; (iv) the effects of green tea and its active components on osteogenesis, osteoblastogenesis, and osteoclastogenesis from human epidemiological, animal, as well as cell culture studies; (v) possible mechanisms explaining the osteoprotective effects of green tea bioactive compounds; (vi) other bioactive components in tea that benefit bone health; and (vii) a summary and future direction of green tea and bone health research and the translational aspects. In general, tea and its bioactive components might decrease the risk of fracture by improving bone mineral density and supporting osteoblastic activities while suppressing osteoclastic activities.
(n° 228) Health potential for functional green teas?
Boon N., Int J Vitam Nutr Res. 2008 Dec;78(6):275-81, Unilever R&D Vlaardingen, Vlaardingen, The Netherlands.
Obesity is a major health problem in the developed and developing world. Many "functional" foods and ingredients are advocated for their effects on body composition but few have consistent scientific support for their efficacy. However, an increasing amount of mechanistic and clinical evidence is building for green tea. The tea plant is naturally rich in a group of antioxidants known as catechins. Unlike black tea, green tea production involves little processing and fermentation and therefore, green tea brews are rich in catechins. Green tea has been suggested to have a number of potential health benefits in areas such as cardiovascular disease, cancer prevention, glucose homeostasis and dental health. Although there is some promising evidence in all of these areas, more data from human intervention trials are needed. A lot of attention has lately been focused on the beneficial effects of green tea on body composition and particularly visceral fat, which has been shown to have a strong link with different components of the metabolic syndrome such as cardiovascular disease and type 2 diabetes. Most, but not all, of the positive results come from a number Asian studies, in which overweight subjects (men and women) consumed green tea for approximately 12 weeks. Finally, green tea may also have measurable acute effects on energy metabolism and fat oxidation and in particular during physical activity, as evidenced by other studies specifically looking at these endpoints. Small cumulative effects on energy metabolism could also be responsible for the longer-tem effects of green tea on body composition, and these long-term effects may also be most apparent in the context of moderate physical activity. However, more research is needed to further clarify the exact mechanisms of action and to extrapolate these findings to non-Asian populations.
(n° 229) Effects of catechin enriched green tea on body composition.
Wang H, Wen Y, Du Y, Yan X, Guo H, Rycroft JA, Boon N, Kovacs EM, Mela DJ., Obesity (Silver Spring). 2010 Apr;18(4):773-9. Epub 2009 Aug 13, Unilever R&D, Shanghai, China.
Obesity is a major health problem in the developed and developing world. Many "functional" foods and ingredients are advocated for their effects on body composition but few have consistent scientific support for their efficacy. However, an increasing amount of mechanistic and clinical evidence is building for green tea (GT). We conclude that consumption of two servings of an extra high-catechin GT leads to improvements in body composition and reduces abdominal fatness in moderately overweight Chinese subjects.
(n° 230) Marked inhibition of growth and invasive parameters of head and neck squamous carcinoma FaDu by a nutrient mixture.
Roomi MW, Roomi NW, Kalinovsky T, Rath M, Niedzwiecki A., Integr Cancer Ther. 2009 Jun;8(2):168-76, Dr Rath Research Institute, Santa Clara, California, USA.
Head and neck squamous cell carcinomas (HNSCCs) are known for their aggressive growth and propensity to metastasize. The authors investigated the effect of a novel nutrient mixture (NM) containing ascorbic acid, lysine, proline, and green tea extract on human HNSCC cell line FaDu in vivo and in vitro. In conclusion, NM has therapeutic potential in the treatment of HNSCC by significantly suppressing tumor growth and significantly inhibiting MMP secretion and invasion of HNSCC cells in vitro.
(n° 231) Protective effects of tea polysaccharides and polyphenols on skin.
Wei X, Liu Y, Xiao J, Wang Y., J Agric Food Chem. 2009 Sep 9;57(17):7757-62, Shanghai Normal University, Shanghai, People's Republic of China.
The protective effects of tea polysaccharides (TPS) and polyphenols (TPP) on skin were investigated. TPS1 (92% TPS), crude TPS2 (20% TPS), and TPP (98%) were tested. The abilities of TPS and TPP to protect the skin were assessed in four aspects: moisture absorption and retention, sunscreen, promoting the proliferation of fibroblast cells, and tyrosinase inhibitory effect. The results indicated that TPP and TPS had complementary advantages and they should be appropriately combined to achieve higher performance when applied as active components of cosmetics.
(n° 232) Green tea and heart health.
Naito Y, Yoshikawa T., J Cardiovasc Pharmacol. 2009 Nov;54(5):385-90, Kyoto Prefectural University of Medicine, Japan.
The adherence of monocytes to vascular endothelial cells is an important early event in atherogenesis. Monocyte adherence to endothelial cells is induced by oxidized low-density lipoprotein (LDL) and mediated by multiple cell-adhesion molecules, including vascular cell-adhesion molecule 1 and intercellular cell-adhesion molecule 1. Enhanced endothelial expression of these molecules by oxidized LDL has been shown to be a critical step in foam cell formation and the development of atherosclerosis. Recent studies have demonstrated that tea catechin, especially (-)-epigallocatechin-3-gallate, inhibits the expression of these molecules by endothelial cells in response to stimulation with oxidized LDL or inflammatory cytokines and the expression of CD11b by monocytic leukocytes. An in vivo study using apolipoprotein E-deficient mice has demonstrated that tea catechin extracts prevent the development of atherosclerosis and that (-)-epigallocatechin-3-gallate effectively reduces the progression of accelerated atherosclerotic plaque formation induced by cuff injury. These data suggest that tea catechin may provide a unique approach to reduce atherosclerosis, although further studies will be necessary to clarify the precise mechanism of these effects, especially the role of metabolites of catechin and the target sites of these compounds.
(n° 233) Green tea epigallocatechin-3-gallate inhibits microsomal prostaglandin E(2) synthase-1.
Koeberle A, Bauer J, Verhoff M, Hoffmann M, Northoff H, Werz O., Biochem Biophys Res Commun. 2009 Oct 16;388(2):350-4. Epub 2009 Aug 6, University of Tuebingen, Tuebingen, Germany.
Prostaglandin (PG)E(2) is a critical lipid mediator connecting chronic inflammation to cancer. The anti-carcinogenic epigallocatechin-3-gallate (EGCG) from green tea (Camellia Sinensis) suppresses cellular PGE(2) biosynthesis, but the underlying molecular mechanisms are unclear. Here, we investigated the interference of EGCG with enzymes involved in PGE(2) biosynthesis, namely cytosolic phospholipase (cPL)A(2), cyclooxygenase (COX)-1 and -2, and microsomal prostaglandin E(2) synthase-1 (mPGES-1). EGCG failed to significantly inhibit isolated COX-2 and cPLA(2) up to 30 microM and moderately blocked isolated COX-1 (IC(50)>30 microM). However, EGCG efficiently inhibited the transformation of PGH(2) to PGE(2) catalyzed by mPGES-1 (IC(50)=1.8 microM). In lipopolysaccharide-stimulated human whole blood, EGCG significantly inhibited PGE(2) generation, whereas the concomitant synthesis of other prostanoids (i.e., 12(S)-hydroxy-5-cis-8,10-trans-heptadecatrienoic acid and 6-keto PGF(1alpha)) was not suppressed. Conclusively, mPGES-1 is a molecular target of EGCG, and inhibition of mPGES-1 is seemingly the predominant mechanism underlying suppression of cellular PGE(2) biosynthesis by EGCG.
(n° 234) Green tea (-)-epigallocatechin-3-gallate inhibits beta-amyloid-induced cognitive dysfunction through modification of secretase activity via inhibition of ERK and NF-kappaB pathways in mice.
Lee JW, Lee YK, Ban JO, Ha TY, Yun YP, Han SB, Oh KW, Hong JT., J Nutr. 2009 Oct;139(10):1987-93. Epub 2009 Aug 5, Chungbuk National University 12, Gaesin-dong, Heungduk-gu, Cheongju, Chungbuk, Korea.
Alzheimer's disease (AD) is characterized by the extracellular deposition of beta-amyloid peptide (Abeta) in cerebral plaques. Abeta is derived from the beta-amyloid precursor protein (APP) by the enzymes alpha-, beta- and gamma-secretase. Compounds that enhance alpha-secretase, but inhibit beta- or gamma-secretase activity, have therapeutic potential in the treatment of AD. Green tea, or its major polyphenolic compound, has been shown to have neuroprotective effects. In this study, we investigated the possible effects of (-)-epigallocatechin-3-gallate (EGCG) on memory dysfunction caused by Abeta through the change of Abeta-induced secretase activities. Paralleled with the suppression of beta- and gamma-secretases by EGCG, we found that EGCG inhibited the activation of extracellular signal-regulated kinase and nuclear transcription factor-kappaB in the Abeta(1-42)-injected mouse brains. In addition, EGCG inhibited Abeta(1-42)-induced apoptotic neuronal cell death in the brain. To further test the ability of EGCG to affect memory, EGCG (3 mg/kg body weight) was administered in drinking water for 1 wk to genetically developed preseniline 2 (PS2) mutant AD mice. Compared with untreated mutant PS2 AD mice, treatment with EGCG enhanced memory function and brain alpha-secretase activity but reduced brain beta- and gamma-secretase activities as well as Abeta levels. Moreover, EGCG inhibited the fibrillization of Abeta in vitro with a half maximal inhibitory concentration of 7.5 mg/L. These studies suggest that EGCG may be a beneficial agent in the prevention of development or progression of AD.
(n° 235) HIV type-1 entry inhibitors with a new mode of action.
Fink RC, Roschek B Jr, Alberte RS., Antivir Chem Chemother. 2009;19(6):243-55, University of Miami Leonard Miller School of Medicine, Miami, FL, USA.
The development of antiviral drugs has provided crucial new means to mitigate or relieve the debilitating effects of many viral pathogens. Regular use of these drugs has led to generation of resistant strains, making the control of many viral infections very difficult, particularly in HIV-seropositive and AIDS patients. A rich source for the discovery of new HIV infection inhibitors has been, and continues to be, the 'mining' of the large diversity of compounds already available in nature, and specifically those from botanical extracts. The compounds that blocked HIV-1 infection were flavonoids and A-type proanthocyanidins. The 50% inhibitory concentration values of these extracts ranged from 0.5 to 201 microg/ml for four different HIV-1 serotypes. Interaction matrices with the elderberry extract and enfuvirtide, a peptide HIV-1 fusion inhibitor, revealed significant super additive effects. This indicates that the compounds in elderberry that prevent HIV-1 infection are likely to bind to viral glycoproteins other than gp41 (the binding site for enfuvirtide). Optimized elderberry, green tea and cinnamon extracts rich in certain flavonoid compounds were shown to block HIV-1 entry and infection in GHOST cells. As such, these types of botanical extracts could provide a starting point for the development of possible safe and reliable cotherapies for HIV-1-positive individuals, as well as for the identification of new small molecules as leading drug candidates for HIV-1 therapeutics and microbicides.
(n° 236) Green tea and death from pneumonia in Japan: the Ohsaki cohort study.
Watanabe I, Kuriyama S, Kakizaki M, Sone T, Ohmori-Matsuda K, Nakaya N, Hozawa A, Tsuji I., Am J Clin Nutr. 2009 Sep;90(3):672-9. Epub 2009 Jul 22, Tohoku University Graduate School of Medicine, Sendai, Japan.
Experimental and animal studies have shown the activities of catechins, the main constituents of green tea, against infectious agents. No data are available on the association between green tea consumption and the risk of pneumonia in humans. We examined the association between green tea consumption and death from pneumonia in humans. Over 12 y of follow-up, we documented 406 deaths from pneumonia. In women, the multivariate HRs of death from pneumonia that were associated with different frequencies of green tea consumption were 1.00 (reference) for <1 cup/d, 0.59 (95% CI: 0.36, 0.98) for 1-2 cups/d, 0.55 (95% CI: 0.33, 0.91) for 3-4 cups/d, and 0.53 (95% CI: 0.33, 0.83) for > or =5 cups/d, respectively (P for trend: 0.008). In men, no significant association was observed. Green tea consumption was associated with a lower risk of death from pneumonia in Japanese women.
(n° 237) Long-term green tea catechin administration prevents spatial learning and memory impairment in senescence-accelerated mouse prone-8 mice by decreasing Abeta1-42 oligomers and upregulating synaptic plasticity-related proteins in the hippocampus.
Li Q, Zhao HF, Zhang ZF, Liu ZG, Pei XR, Wang JB, Li Y., Neuroscience. 2009 Oct 20;163(3):741-9. Epub 2009 Jul 25, Peking University, Beijing, PR China.
The senescence-accelerated mouse prone-8 (SAMP8) is characterized by early onset of learning and memory deficits along with spontaneous overproduction of soluble beta-amyloid peptide (Abeta) in the brain. The activity of the protein kinase A/cAMP-response element binding protein (PKA/CREB) pathway, one of the molecular targets of Abeta oligomers which is crucial for late long-term potentiation and long-term memory formation, was significantly increased after GTC administration. We also found that chronic 0.05% or 0.1% GTC consumption prevented the reductions of three representative proteins of synaptic function and synaptic structure, including brain-derived neurotrophic factor(BDNF), post-synaptic density protein-95 (PSD95) and Ca(2+)/calmodulin-dependent protein kinase II (CaMKII). These results demonstrated that long-term 0.05% or 0.1% green tea catechin administration may prevent spatial learning and memory decline of SAMP8 mice by decreasing Abeta(1-42) oligomers and upregulating synaptic plasticity-related proteins in the hippocampus.
(n° 238) Greenselect Phytosome as an adjunct to a low-calorie diet for treatment of obesity: a clinical trial.
Di Pierro F, Menghi AB, Barreca A, Lucarelli M, Calandrelli A., Altern Med Rev. 2009 Jun;14(2):154-60.
A recently developed oral formulation in the form of coated tablets (Monoselect Camellia) (MonCam) containing highly bioavailable green tea extract (GreenSelect Phytosome) was tested in obese subjects (n=100) of both genders on a hypocaloric diet. After 90 days of treatment, significant weight loss and decreased body mass index (BMI) were observed in the group taking the herbal extract (14-kg loss in the green tea group compared to a 5-kg loss in the diet-only group); waistline was reduced only in male subjects. Besides the effect on weight and BMI, biochemical parameters (LDL-, HDL-, and total cholesterol, triglycerides, growth hormone, insulin-like growth factor-1, insulin, and cortisol) were improved in both groups. Leptin, not tested in the diet-only group, was reduced in patients taking MonCam. Taking into consideration the high safety profile of the product and the total absence of adverse effects observed during and after the trial, MonCam appears to be a safe and effective tool for weight loss.
(n° 239) Green tea (Camellia Sinensis) for the prevention of cancer.
Boehm K, Borrelli F, Ernst E, Habacher G, Hung SK, Milazzo S, Horneber M., Cochrane Database Syst Rev. 2009 Jul 8;(3):CD005004, Klinikum Nord, Nuernberg, Germany.
Tea is one of the most commonly consumed beverages worldwide. Teas from the plant Camellia Sinensis can be grouped into green, black and oolong tea. Cross-culturally tea drinking habits vary. Camellia Sinensis contains the active ingredient polyphenol, which has a subgroup known as catechins. Catechins are powerful antioxidants. It has been suggested that green tea polyphenol may inhibit cell proliferation and observational studies have suggested that green tea may have cancer-preventative effects. Results from studies assessing associations between green tea and risk of digestive tract cancer incidence were highly contradictory. There was limited evidence that green tea could reduce the incidence of liver cancer. The evidence for esophageal, gastric, colon, rectum, and pancreatic cancer was conflicting. In prostate cancer, observational studies with higher methodological quality and the only included RCT suggested a decreased risk in men consuming higher quantities green tea or green tea extracts. However, there was limited to moderate evidence that the consumption of green tea reduced the risk of lung cancer, especially in men, and urinary bladder cancer or that it could even increase the risk of the latter. There was moderate to strong evidence that green tea consumption does not decrease the risk of dying from gastric cancer. There was limited moderate to strong evidence for lung, pancreatic and colorectal cancer.There is insufficient and conflicting evidence to give any firm recommendations regarding green tea consumption for cancer prevention. The results of this review, including its trends of associations, need to be interpreted with caution and their generalisability is questionable, as the majority of included studies were carried out in Asia (n = 47) where the tea drinking culture is pronounced. Desirable green tea intake is 3 to 5 cups per day (up to 1200 ml/day), providing a minimum of 250 mg/day catechins. If not exceeding the daily recommended allowance, those who enjoy a cup of green tea should continue its consumption. Drinking green tea appears to be safe at moderate, regular and habitual use.
(n° 240) Inhibitory effect of tea polyphenols on local tissue damage induced by snake venoms.
Pithayanukul P, Leanpolchareanchai J, Bavovada R., Phytother Res. 2010 Apr;24(4):632, Mahidol University, Bangkok, Thailand.
The methanolic extract of fresh tea leaves of Camellia Sinensis L. (Theaceae) (CS) was assayed for its potential to inhibit enzymes with hydrolytic activity in Naja naja kaouthia Lesson (Elapidae) and Calloselasma rhodostoma Kuhl (Viperidae) venoms. It is suggested that the inhibitory potential of the CS extract against local tissue damage induced by snake venoms may be attributed to complexation and chelation between the venom proteins and the phenolic contents of the extract.
(n° 241) Quantitative analysis of saponins in a tea-leaf extract and their antihypercholesterolemic activity.
Matsui Y, Kobayashi K, Masuda H, Kigoshi H, Akao M, Sakurai H, Kumagai H., Biosci Biotechnol Biochem. 2009 Jul;73(7):1513-9. Epub 2009 Jul 7, Laboratory of Health Materials, Ogawa & Co, Ltd, Urayasu, Chiba, Japan.
A novel simple method using liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS) and LC/UV was established for the quantification of saponins in an extract from green tea leaves. The amount of saponins in a fraction with high in vitro antihypercholesterolemic activity, Fr2-3, was determined to be 72%. An in vivo experiment showed that the addition of 0.5% Fr2-3 to a high-cholesterol diet suppressed the increase in serum cholesterol levels in rats. Fr2-3 induced a decrease in the liver cholesterol and triglyceride levels and an increase in the fecal excretion of cholesterol. These results indicate tea-leaf saponins to be the active components in Fr2-3 and that these saponins exhibited antihypercholesterolemic activity by inhibiting cholesterol absorption in the intestines.
(n° 242) Induction of apoptosis by tea polyphenols mediated through mitochondrial cell death pathway in mouse skin tumors.
Roy P, Nigam N, George J, Srivastava S, Shukla Y., Cancer Biol Ther. 2009 Jul;8(13):1281-7, Indian Institute of Toxicology Research (CSIR), Lucknow, India.
Many naturally occurring phytochemicals have shown cancer chemopreventive potential in a variety of bioassay systems. One such naturally occurring biologically active compound is tea Camellia Sinensis, which is the most consumed beverage in the world after water. The most abundant and active constituents of tea are polyphenols (epigallocatechin gallate and theaflavins). Tea polyphenols treatment along with DMBA exposure resulted in upregulation of p53, and proapoptotic protein Bax, whereas enhanced expression of antiapoptotic proteins, Bcl-2 and survivin by DMBA were downregulated. Further, we showed that tea polyphenols supplementation resulted in release of cytochrome c, caspases activation, and increase in apoptotic protease activating factor and poly (ADP-ribose) polymerase cleavage as mechanism of apoptosis induction. The results also provide strong evidence that BTP is a better chemopreventive agent against skin tumorigenesis as compared to GTP at the tested dose levels. Thus, we can conclude that the polyphenolic constituents present in black tea and green tea <hr />induce mitochondrial pathway of apoptosis and hence can be used as a potential chemopreventive agents against skin cancer.
(n° 243) Acylated oleanane-type triterpene saponins with acceleration of gastrointestinal transit and inhibitory effect on pancreatic lipase from flower buds of chinese tea plant (Camellia Sinensis).
Yoshikawa M, Sugimoto S, Kato Y, Nakamura S, Wang T, Yamashita C, Matsuda H., Chem Biodivers. 2009 Jun;6(6):903-15, Kyoto Pharmaceutical University, Misasagi, Yamashina-ku, Kyoto, Japan.
The MeOH extract and its BuOH-soluble fraction (crude saponin fraction) from the flower buds of Chinese tea plant (Camellia Sinensis (L.) O. KUNTZE; Fujian Province) were found to exhibit accelerating effects on gastrointestinal transit in mice and inhibitory effects against pancreatic lipase. From the BuOH-soluble fraction, three new acylated oleanane-type triterpene oligoglycosides, chakasaponins I, II, and III (1-3, resp.), were isolated together with 13 known compounds. The chemical structures 1-3 were elucidated on the basis of chemical and physicochemical evidence. Compounds 1-3 showed accelerating effects on gastrointestinal transit in mice and inhibitory effects against porcine pancreatic lipase (IC(50)=150-530 microM).
(n° 244) Inhibitory effect of commercial green tea and rosemary leaf powders on the growth of foodborne pathogens in laboratory media and oriental-style rice cakes.
Lee SY, Gwon SY, Kim SJ, Moon BK., J Food Prot. 2009 May;72(5):1107-11, Chung-Ang University, Daedeok-myeon, Anseong-si, Gyeonggi-do, South Korea.
The antimicrobial effects of green tea and rosemary added to foods as antagonists to foodborne pathogens were determined in laboratory media and oriental-style rice cakes. Green tea was particularly effective against B. cereus, S. aureus, and L. monocytogenes, and rosemary was strongly inhibitory against B. cereus and S. aureus. The addition of 1 or 3% green tea or rosemary to rice cakes did not significantly reduce total aerobic counts; however, levels of B. cereus and S. aureus were significantly reduced in rice cakes stored for 3 days at room temperature (22 degrees C). The order of antimicrobial activities against B. cereus in rice cake was 1% rosemary < 1% green tea < 3% rosemary = 3% green tea. These results indicate that the use of natural plant materials such as green tea and rosemary could improve the microbial quality of foods in addition to their functional properties.
(n° 245) Tea polyphenols inhibit cyclooxygenase-2 expression and block activation of nuclear factor-kappa B and Akt in diethylnitrosoamine induced lung tumors in Swiss mice.
Roy P, Nigam N, Singh M, George J, Srivastava S, Naqvi H, Shukla Y., Invest New Drugs. 2010 Aug;28(4):466-71. Epub 2009 Jun 11, Indian Institute of Toxicology Research, Lucknow, India.
Due to lack of validated screening methods and hence poor prognosis, treatment of lung cancer has not still improved up to the expectations. Therefore, risk of lung cancer needs to be minimized by efficient preventive measures. Tea (Camellia Sinensis) and its bioactive polyphenols have been associated with prevention of human cancer for several organs. Thus, intake of tea polyphenols seems to be a viable mean to control lung cancer burden. GTP and BTP treatment inhibited the expression of Akt, cyclooxygenase-2 and inactivated nuclear factor-kappa B via blocking phosphorylation and subsequent degradation of IkappaB alpha. Thus, the study suggests that polyphenolic constituents of both cultivars of tea, i.e. green and black, have chemopreventive effects in DEN induced lung tumorigenesis in Swiss albino mice.
(n° 246) Complementary and alternative medicine for the treatment of type 2 diabetes.
Nahas R, Moher M., Can Fam Physician. 2009 Jun;55(6):591-6, Department of Family Medicine at the University of Ottawa, Ottawa, Canada.
To review clinical evidence supporting complementary and alternative medicine interventions for improving glycemic control in type 2 diabetes mellitus. Chromium reduced glycosylated hemoglobin (HbA(1c)) and fasting blood glucose (FBG) levels in a large meta-analysis. Gymnema sylvestre reduced HbA(1c) levels in 2 small open-label trials. Cinnamon improved FBG but its effects on HbA(1c) are unknown. Bitter melon had no effect in 2 small trials. Fibre had no consistent effect on HbA(1c) or FBG in 12 small trials. Green tea reduced FBG levels in 1 of 3 small trials. Fenugreek reduced FBG in 1 of 3 small trials. Vanadium reduced FBG in small, uncontrolled trials. There were no trials evaluating microvascular or macrovascular complications or other clinical end points. Chromium, and possibly gymnema, appears to improve glycemic control. Fibre, green tea, and fenugreek have other benefits but there is little evidence that they substantially improve glycemic control. Further research on bitter melon and cinnamon is warranted. There is no complementary and alternative medicine research addressing microvascular or macrovascular clinical outcomes.
(n° 247) Green tea and prostate cancer: from bench to clinic.
Pandey M, Gupta S., Front Biosci (Elite Ed). 2009 Jun 1;1:13-25, Case Western Reserve University, Clevelamd, OH, USA.
Green tea, the most popular beverage next to water, is a rich source of tea catechins and has potential to be developed as a chemopreventive agent for prostate cancer. For centuries it has been used in traditional medicine in Far-East countries. Male populations in these countries where large quantities of green tea are consumed on regular basis have the lowest incidence of prostate cancer. The review concludes with a brief discussion of the future direction and development of clinical trials employing green tea catechins which could be developed for prevention and/or intervention of prostate cancer.
(n° 248) Can green tea do that? A literature review of the clinical evidence.
Clement Y., Prev Med. 2009 Aug-Sep;49(2-3):83-7. Epub 2009 May 22, The University of the West Indies, St. Augustine, Trinidad and Tobago.
Habitual green tea consumption has long been associated with health benefits including chemoprevention and cardiovascular protection. This non-systematic literature review presents the clinical evidence to date. Observational studies are inconclusive on the benefits of habitual consumption of green tea in the prevention of most cancers. However, there are trends towards prevention in breast and prostate cancers. Interventional studies have demonstrated reduction in relapses following surgical resection in colorectal adenomas and increased survival rates in epithelial ovarian cancer. Observational studies indicate that green tea may provide protection against hypertension and reduce the risk for stroke, and interventional studies are providing biochemical and physiological evidence. Although the overall clinical evidence is inconclusive, habitual green tea consumption may be providing some level of chemoprevention in prostate and breast cancer. Green tea may also attenuate the risk factors association with the development of atherosclerosis thus reducing the incidence of cardiovascular events and stoke.
(n° 249) Cell viability of normal human skin fibroblast and fibroblasts derived from granulation tissue: effects of nutraceuticals.
Borawska MH, Czechowska SK, Markiewicz R, Hayirli A, Olszewska E, Sahin K., J Med Food. 2009 Apr;12(2):429-34, Medical University of Bialystok, Bialystok, Poland.
The effects of lycopene, genistein, and epigallocatechin-3-gallate (EGCG) on cell viability were tested in vitro using a normal human skin fibroblast (NHSF) cell line (CRL-1474) and granulation tissue fibroblasts (GTFs) obtained from a patient with middle ear cholesteatoma. Data were analyzed using two-way analysis of variance separately for each compound. Lycopene addition decreased viability of NHSFs and GTFs compared with THF addition (64.1%, 60.5%, and 100%, respectively, P < .0001). Genistein addition also increased viability of both NHSFs and GTFs compared with DMSO addition (P < .02). Increasing EGCG concentration tended to cause a linear increase in viability of NHSFs but did not alter viability of GTFs (P < .10). Our data suggest that genistein and EGCG but not lycopene could help maintaining or improving skin health through enhancing viability of skin fibroblasts.
(n° 250) The main green tea polyphenol epigallocatechin-3-gallate counteracts semen-mediated enhancement of HIV infection.
Hauber I, Hohenberg H, Holstermann B, Hunstein W, Hauber J., Proc Natl Acad Sci U S A. 2009 Jun 2;106(22):9033-8. Epub 2009 May 18, Heinrich-Pette-Institute for Experimental Virology and Immunology, Hamburg, Germany.
Peptide fragments, derived from prostatic acidic phosphatase, are secreted in large amounts into human semen and form amyloid fibrils. These fibrillar structures, termed semen-derived enhancer of virus infection (SEVI), capture HIV virions and direct them to target cells. Thus, SEVI appears to be an important infectivity factor of HIV during sexual transmission. Here, we are able to demonstrate that epigallocatechin-3-gallate (EGCG), the major active constituent of green tea, targets SEVI for degradation. Furthermore, it is shown that EGCG inhibits SEVI activity and abrogates semen-mediated enhancement of HIV-1 infection in the absence of cellular toxicity. Therefore, EGCG appears to be a promising supplement to antiretroviral microbicides to reduce sexual transmission of HIV-1.
(n° 251) Protective effects of green tea polyphenols on cognitive impairments induced by psychological stress in rats.
Chen WQ, Zhao XL, Hou Y, Li ST, Hong Y, Wang DL, Cheng YY., Behav Brain Res. 2009 Aug 24;202(1):71-6. Epub 2009 Mar 21, Institute of Health and Environmental Medicine, Tianjin, China.
This study was conducted to explore the modulation of GTPs on cognitive performances in psychological stress rats. Our results suggested that psychological stress impaired body's cognitive performances, and moderate GTPs modulation could improve these abnormal changes. To our knowledge, this is the first report showing the improving effects of GTPs on cognitive dysfunctions induced by psychological stress.
(n° 252) Green tea catechins, alleviate hepatic lipidemic-oxidative injury in Wistar rats fed an atherogenic diet.
Ramesh E, Jayakumar T, Elanchezhian R, Sakthivel M, Geraldine P, Thomas PA., Chem Biol Interact. 2009 Jun 15;180(1):10-9. Epub 2009 Mar 9, Bharathidasan University, Tiruchirappalli, Tamil Nadu, India.
In the present study, the efficacy of green tea catechins (GTC from the plant Camellia Sinensis), with epigallocatechin gallate (EGCG), as the major component, was studied in relation to hepatic oxidative abnormalities in atherosclerotic rats. Histopathological studies were performed to provide direct evidence of the atherogenic diet-induced hepatic changes and of the hepatoprotective effect of GTC. These results suggest that EGCG as a major component of green tea catechins may protect against the hepatic abnormalities occurring in Wistar rats fed an atherogenic diet.
(n° 253) The green tea polyphenol (-)-epigallocatechin-3-gallate inhibits leukocyte activation by bacterial formylpeptide through the receptor FPR.
Zhu J, Wang O, Ruan L, Hou X, Cui Y, Wang JM, Le Y., Int Immunopharmacol. 2009 Aug;9(9):1126-30. Epub 2009 May 6, Shanghai Institutes for Biological Sciences, China.
Although green tea polyphenol catechin is considered as a potential anti-inflammatory agent, its effect on bacterial component-induced inflammation has been poorly investigated. Mechanistic studies revealed that EGCG dose-dependently suppressed fMLF-induced calcium flux in monocytic cells and ETFR cells. fMLF-induced ETFR cell migration was significantly inhibited by a specific MEK1/2 inhibitor, PD98059, which was associated with reduction in fMLF-induced ERK1/2 phosphorylation. These results suggest that EGCG inhibits FPR-mediated leukocyte activation thus is a promising anti-inflammatory compound.
(n° 254) Senescence mediated redox imbalance in cardiac tissue: Antioxidant rejuvenating potential of green tea extract.
Kumaran VS, Arulmathi K, Kalaiselvi P., Nutrition. 2009 Jul-Aug;25(7-8):847-54. Epub 2009 Apr 28, University of Madras, Chennai, India.
The activities and capacities of antioxidant systems of tissue cells are declined during aging, leading to the gradual loss of pro-oxidant/antioxidant balance and accumulation of oxidative damage. Hence, the present study evaluated the role of green tea extract (GTE), rich in polyphenols, in combating age-associated macromolecular damage in rat cardiac tissue. Significant increases in lipid peroxidation, protein carbonyls, and marked decreases in glutathione redox status, protein thiols, and activities of enzymatic and non-enzymatic antioxidants were observed in aged rats compared with young rats. Supplementation of GTE (100 mg/kg of body weight per day) orally for 30 days ameliorated these changes significantly. This study accredits GTE's antioxidant rejuvenating potency and its role in the amelioration of senescence-mediated redox imbalance in aged rat cardiac tissue.
(n° 255) Green tea: nature's defense against malignancies.
Butt MS, Sultan MT., Crit Rev Food Sci Nutr. 2009 May;49(5):463-73, University of Agriculture, Faisalabad.
The current practice of introducing phytochemicals to support the immune system or fight against diseases is based on centuries old traditions. The pharmacological actions of green tea are mainly attributed to polyphenols that includes epigallocatechin-3-gallate (EGCG), epicatechin, epicatechin-3-gallate, epigallocatechin. Green tea and its components effectively mitigate cellular damage arising due to oxidative stress. Green tea is supposed to enhance humoral and cell-mediated immunity, decreasing the risk of certain cancers, and may have certain advantage in treating inflammatory disorders. Much of the cancer chemopreventive properties of green tea are mediated by EGCG that induces apoptosis and promotes cell growth arrest, by altering the expression of cell cycle regulatory proteins, activating killer caspases, and suppressing nuclear factor kappa-B activation. Besides, it regulates and promotes IL-23 dependent DNA repair and stimulates cytotoxic T cells activities in a tumor microenvironment. It also blocks carcinogenesis by modulating the signal transduction pathways involved in cell proliferation, transformation, inflammation and metastasis. The review is intended to highlight the chemistry of green tea, its antioxidant potential, its immunopotentiating properties and mode of action against various cancer cell lines that showed its potential as a chemopreventive agent against colon, skin, lung, prostate, and breast cancer.
(n° 256) A thought on the biological activities of black tea.
Sharma V, Rao LJ., Crit Rev Food Sci Nutr. 2009 May;49(5):379-404, Central Food Technological Research Institute, Mysore, India.
Tea is the most widely used ancient beverage in the world and black tea possesses many biological effects on the organisms. It acts as an effective antioxidant because of its free radical-scavenging and metal-chelating ability. Due to this, it is active against inflammation, clastogenesis, and several types of cancer. Tea reduces DNA damage and mutagenesis due to oxidative stress or the presence of pro-mutagens through antioxidant function, blocking activation pathways of mutagens, suppressing transcription of enzymes involved etc. Inhibition of low-density lipoprotein (LDL) peroxidation, suppression of fatty acid synthase etc., suggest that tea may have a role in preventing cardiovascular diseases. Some epidemiological studies support the protective role of black tea against cardiovascular diseases but some do not. Besides, black tea has beneficial effects on the gastrointestinal tract; it affects motility, absorption, microflora etc., by influencing the hormonal balance and antioxidant function black tea improves bone mineral density. It is also antiviral due to its enzyme-inhibiting and receptor-blocking properties. Although its role in cancers of the gastrointestinal tract, liver, and prostate is confirmed, its effect against urinary tract cancer is uncertain and further studies are required. Apart from these, excess consumption may lead to the formation of a stained pellicle layer on teeth, which is difficult to eliminate, inhibits trypsin, influences mineral absorption, causes convulsions etc. Excess caffeine intake may have adverse effects on selected organs as reported in studies on some organisms. These reports indicate that there is a wide scope of further research for the efficient use of black tea active conserves/isolates to reap health benefits.
(n° 257) Anti-cariogenic effects of polyphenols from plant stimulant beverages (cocoa, coffee, tea).
Ferrazzano GF, Amato I, Ingenito A, De Natale A, Pollio A., Fitoterapia. 2009 Jul;80(5):255-62. Epub 2009 May 3, University of Naples Federico II, Naples, Italy.
Polyphenols occurring in cocoa, coffee and tea can have a role in the prevention of cariogenic processes, due to their antibacterial action. Cocoa polyphenol pentamers significantly reduce biofilm formation and acid production by Streptococcus mutans and S. sanguinis. In the same way, trigonelline, caffeine and chlorogenic acid occurring in green and roasted coffee interfere with S. mutans adsorption to saliva-coated hydroxyapatite beads. Studies carried out on green, oolong and black tea indicate that tea polyphenols exert an anti-caries effect via an anti-microbial mode-of-action, and galloyl esters of (-)-epicatechin, (-)-epigallocatechin and (-)-gallocatechin show increasing antibacterial activities. The anti-cariogenic effects against alpha-haemolytic streptococci showed by polyphenols from cocoa, coffee, and tea suggest further studies to a possible application of these beverages in the prevention of pathogenesis of dental caries.
(n° 258) Epigenetic modulation of the retinoid X receptor alpha by green tea in the azoxymethane-Apc Min/+ mouse model of intestinal cancer.
Volate SR, Muga SJ, Issa AY, Nitcheva D, Smith T, Wargovich MJ., Mol Carcinog. 2009 Oct;48(10):920-33, University of South Carolina, Columbia, South Carolina, USA.
We investigated the possible mechanisms of inhibition of colorectal carcinogenesis by green tea (GT) in azoxymethane-treated (AOM) Apc(Min/+) mice. The results suggest that a low concentration of GT is sufficient to desilence RXR alpha and inhibit intestinal tumorigenesis in the Apc(Min/+) mouse.
(n° 259) Effect of aqueous extracts of black and green teas in arsenic-induced toxicity in rabbits.
Raihan SZ, Chowdhury AK, Rabbani GH, Marni F, Ali MS, Nahar L, Sarker SD., Phytother Res. 2009 Nov;23(11):1603-8, University of Dhaka, Dhaka, Bangladesh.
Arsenic causes oxidative stress in the body. Its administration (3 mg/kg/day) for 14 days in rabbits resulted in a significant reduction of whole blood glutathione (GSH), and elevation of thiobarbituric acid reactive substances (TBARS) and the index of nitrite/nitrate (NOx) levels. These are the markers of oxidative stress. Both black tea (BT) and green tea (GT) (Camellia Sinensis), when administered to the arsenic-treated rabbits for 14 days, caused a significant elevation of the depleted GSH level to 53.12% and 57.47%, respectively. When arsenic and black tea were given concurrently to another group the results were even more pronounced. The polyphenol components of black and green tea were 27.69% and 29.71% of the dry weight of the total extracts, respectively. These results indicated that arsenic-induced toxicities in rabbits were significantly reversed by the black and green tea polyphenols. The greater activity of green tea than that of black tea correlates with the slightly higher content of polyphenols in green tea.
(n° 260) Green tea polyphenols attenuate glial swelling and mitochondrial dysfunction following oxygen-glucose deprivation in cultures.
Panickar KS, Polansky MM, Anderson RA., Nutr Neurosci. 2009 Jun;12(3):105-13, United States Department of Agriculture, Beltsville, Maryland, USA.
Astrocyte swelling is a major component of cytotoxic brain edema in ischemia. Oxidative stress and mitochondrial dysfunction have been hypothesized to contribute to such swelling in cultures. Our findings indicate a protective effect of GTE in cell swelling in ischemic injury and such protective effects may be mediated by its effect on the mitochondria. It appears that effects on cell swelling are mediated by the concerted action of more than one of the individual components of GTE.
(n° 261) Variable inhibitory effect of different brands of commercial herbal supplements on human cytochrome P-450 CYP3A4.
Wanwimolruk S, Wong K, Wanwimolruk P., Drug Metabol Drug Interact. 2009;24(1):17-35, Loma Linda University, Loma Linda, CA, USA.
The use of herbal supplements has increased dramatically, making drug interactions with these supplements a major concern. Because herbal supplements are not subject to the same regulations as prescription drugs, we hypothesize that the content of their active ingredients may vary among manufacturers, potentially causing a large variation in therapeutic outcome. The present study aimed to test this hypothesis on commonly used herbal products, i.e. black cohosh (BC), grape seed extract (GSE), green tea extract (GTE) and ginseng. This study suggests that GTE use may cause significant interactions with drugs metabolized by CYP3A4. However, the effect on CYP3A4 varied among different brands of GTE, possibly due to variations in their content of the herbal product's active ingredients.
(n° 262) Green tea polyphenols inhibit testosterone production in rat Leydig cells.
Figueiroa MS, César Vieira JS, Leite DS, Filho RC, Ferreira F, Gouveia PS, Udrisar DP, Wanderley MI, Federal University of Pernambuco, Recife, PE, Brazil.
This study investigated the acute effects of green tea extract (GTE) and its polyphenol constituents, (-)-epigallocatechin-3-gallate (EGCG) and (-)-epicatechin (EC), on basal and stimulated testosterone production by rat Leydig cells in vitroThe inhibitory effects of GTE may be explained by the action of its principal component, EGCG, and the presence of a gallate group in its structure seems important for its high efficacy in inhibiting testosterone production. The mechanisms underlying the effects of GTE and EGCG involve the inhibition of the PKA/PKC signalling pathways, as well as the inhibition of P450 side-chain cleavage enzyme and 17beta-hydroxysteroid dehydrogenase function.
(n° 263) Green tea extract supplement reduces D-galactosamine-induced acute liver injury by inhibition of apoptotic and proinflammatory signaling.
Lin BR, Yu CJ, Chen WC, Lee HS, Chang HM, Lee YC, Chien CT, Chen CF., J Biomed Sci. 2009 Mar 25;16:35, National Taiwan University College of Medicine, Taipei, Taiwan.
Oxidative stress and inflammation contributed to the propagation of acute liver injury (ALI). The present study was undertaken to determine whether D-galactosamine (D-GalN) induces ALI via the mitochondrial apoptosis- and proinflammatory cytokine-signaling pathways, and possible mechanism(s) by which green tea (GT) extract modulates the apoptotic and proinflammatory signaling in rat. GT pretreatment attenuated ROS production, mitochondrial apoptosis- and proinflammatory cytokine-signaling pathway, plasma ALT and cytokines levels, biliary acute phase proteins secretion and hepatic pathology by the enhancement of anti-apoptotic mechanisms. In conclusion, D-GalN induced ALI via hypoxia/hypoperfusion-enhanced mitochondrial apoptosis- and proinflammatory cytokine-signaling pathway, contributing to oxidative stress and inflammation in the liver. GT can counteract the D-GalN-induced ALI via the attenuation of apoptotic and proinflammatory signaling by the upregulation of anti-apoptotic mechanism.
(n° 264) Protective action of aqueous black tea (Camellia Sinensis) extract (BTE) against ovariectomy-induced oxidative stress of mononuclear cells and its associated progression of bone loss.
Das AS, Mukherjee M, Das D, Mitra C., Phytother Res. 2009 Sep;23(9):1287-94, Presidency College, Kolkata, India.
The protective action of aqueous black tea extract (BTE) against ovariectomy-induced oxidative stress of mononuclear cells and its associated progression of bone loss was demonstrated in this study. The results indicate that BTE was effective in preserving and restoring skeletal health by reducing the number of active osteoclasts. Such changes with BTE supplementation were steadily linked with the reduced oxidative stress of mononuclear cells, serum levels of bone resorbing cytokines, osteoclast differentiation factor and resorption markers. The results of the bone breaking force, histological and histomorphometric analyses further supported the hypothesis. This study suggests that BTE has both protective and restorative actions against ovariectomy-induced mononuclear cell oxidative stress and associated bone loss.
(n° 265) Evaluation of free radical-scavenging and antihemolytic activities of quince (Cydonia oblonga) leaf: a comparative study with green tea (Camellia Sinensis).
Costa RM, Magalhães AS, Pereira JA, Andrade PB, Valentão P, Carvalho M, Silva BM., Food Chem Toxicol. 2009 Apr;47(4):860-5, Universidade Fernando Pessoa, Porto, Portugal.
This study aimed to determine the phenolic profile and to investigate the antioxidant potential of quince (Cydonia oblonga) leaf, comparing it with green tea (Camellia Sinensis). For these purposes, methanolic extracts were prepared and phenolics content of quince leaf was determined by HPLC/UV. Quince leaf extracts showed similar DPPH radical-scavenging activities (EC50 mean value of 21.6 +/- 3.5 microg/ml) but significantly lower than that presented by green tea extract (EC50 mean value of 12.7 +/- 0.1 microg/ml). Under the oxidative action of AAPH, quince leaf methanolic extract significantly protected the erythrocyte membrane from hemolysis in a similar manner to that found for green tea (IC50 mean value of 30.7 +/- 6.7 and 24.3 +/- 9.6 microg/ml, respectively, P > 0.05). These results point that quince leaf may have application as preventive or therapeutic agent in diseases in which free radicals are involved.
(n° 266) Regulation of cell growth through cell cycle arrest and apoptosis in HPV 16 positive human cervical cancer cells by tea polyphenols.
Singh M, Tyagi S, Bhui K, Prasad S, Shukla Y., Invest New Drugs. 2010 Jun;28(3):216-24. Epub 2009 Mar 7, Indian Institute of Toxicology Research Council of Scientific and Industrial Research, Lucknow, India.
Cervical cancer is the second most common malignant neoplasm in women, in terms of both incidence and mortality rates worldwide. The polyphenolic constituents of tea (Camellia Sinensis) have gained considerable attention because of its anti-cancer properties against a variety of cancers. Here we studied the effects of green and black tea polyphenols (GTP and BTP), on cellular proliferation and cell death in the SiHa cells (human cervical cancer) expressing the human papilloma virus (HPV)-16. The result showed that both GTP and BTP inhibited proliferation of cells in dose and time dependent manner. Cell cycle analysis showed anti-proliferative effect of GTP which is associated with an increase in the G2/M phase and apoptotic effect of BTP in 24 h treated SiHa cells. Further, on increase of incubation time for 48 h, GTP caused induction of apoptosis up to 20% of SiHa cells. The role GTP and BTP in apoptosis was further confirmed by reduction in mitochondrial membrane potential and increased levels of membrane phosphatidylserine. Thus, our data suggests that tea polyphenols exhibit anti-cancer potential against cervical cancer by inhibition of cell growth and induction of apoptosis.
(n° 267) Green tea extract protects rats against myocardial infarction associated with left anterior descending coronary artery ligation.
Hsieh SR, Tsai DC, Chen JY, Tsai SW, Liou YM., Pflugers Arch. 2009 Aug;458(4):631-42. Epub 2009 Mar 5, Taichung Veterans General Hospital, Taichung, Taiwan.
There is increasing evidence that green tea polyphenols can protect against myocardial damage. Recently, we showed that they bind to cardiac troponin C and alter myofilament Ca(2+) sensitivity in cardiac muscle. Supplementation with 400 mg/kg/day of GTE for 4, 18, or 46 days had beneficial effects in preventing the hemodynamic changes. Histopathological studies showed that GTE attenuated the progressive remodeling seen after myocardial injury. Echocardiography confirmed that GTE prevented LV enlargement and improved LV performance in post-MI rats. In addition, we showed that GTE supplementation for 18 or 46 days increased the myofilament Ca(2+) sensitivity of the ischemic myocardium in post-MI rats. These results validate the novel action of green tea polyphenols in protecting against myocardial damage and enhancing cardiac contractility by modulating myofilament Ca(2+) sensitivity in post-MI rats.
(n° 268) Awa (Tokushima) lactate-fermented tea as well as green tea enhance the effect of diet restriction on obesity in rats.
Sogawa M, Seura T, Kohno S, Hirasaka K, Yamaguchi Y, Takagaki R, Harada A, Okumura Y, Yamamoto S, Kishi K, Nikawa T., J Med Invest. 2009 Feb;56(1-2):42-8, the Graduate School at Shikoku University, Tokushima, Japan.
Drinking tea is recommended for promoting health due to its bioactive nutrients, such as catechins and caffeine. In Tokushima area, we have a unique traditional tea, named Awa tea, which are fermented with Lactobacillus pentosus and Lactobacillus plantarum. Our results indicate that Awa lactate-fermented tea as well as green tea similarly enhance the effect of diet restriction on obesity, at least in part, through the increase in fat energy consumption and the decrease in fat absorption in rats.
(n° 269) Study on the theraputic effect of plants of Camellia genus on osteoporosis. [Article in Chinese]
Tang L, Feng BM, Shi LY, Wu XJ, Shi HB, Miao YB, Wang YQ., Zhong Yao Cai. 2008 Oct;31(10):1540-4, Dalian University, Dalian, China.
Extracts of Camellia japonica and Camellia oleifera were given to rats with osteoporosis induced by retinoic acid, some indexes of rats were measured and compared with those of modle group, control group and positive control group, including weight/length (G/L), bone density, earth and calcium content of bone, morphology change and serum calcium, tartrate-resistant acid phosphatase and alkaline phosphatase. We also compared effective intensity between different groups in adqulis crude drug dosage. The results of this study indicated that effects of ethanol extracts of seed from Camellia japonica on anti-osteoporosis with retinoic acid were the strongest. Ethanol extracts of seed from Camellia japonica , ethanol extracts of leaves from Camellia Oleifera, and aqueous extracts of leaves from Camellia Oleifera were stronger than positive control drug. The other extracts didnt show obvious anti-osteoporotic effects. Eventually the strength order of each group on anti-osteoporosis was as following: ethanol extracts of seed from Camellia japonica > ethanol extracts of leaves from Camellia Oleifera > aqueous extracts of leaves from Camellia Oleifera > aqueous extracts of seed from Camellia Oleifera > positive control drug > aqueous extracts of seed from Camellia Japonica. Plants of Camellia genus have different degree anti-osteoporosis effect, which can offer significant theory basis for progressive investigation and exploitation of them.
(n° 270) Epigallocatechin-gallate modulates chemotherapy-induced apoptosis in human cholangiocarcinoma cells.
Lang M, Henson R, Braconi C, Patel T., Liver Int. 2009 May;29(5):670-7. Epub 2009 Feb 17, Texas A&M University Health Sciences Center, College of Medicine, Temple, TX, USA.
Green tea polyphenols are chemopreventive in several cancer models but their use as adjunctive therapeutic agents for cancer is unknown. Epigallocatechin-gallate (EGCG), but not the structurally related catechin epigallocatechin, sensitized cells to apoptosis induced by gemcitabine (GEM), mitomycin C or 5-fluorouracil in vitro. Mitochondrial membrane depolarization, cytosolic cytochrome c expression and apoptosis were increased in cells incubated with EGCG and GEM compared with either agent alone. Furthermore, EGCG decreased in vivo growth and increased the sensitivity to GEM of Mz-ChA-1 cell xenografts in nude mice. The green tea polyphenol EGCG sensitizes human cholangiocarcinoma cells to chemotherapy-induced apoptosis and warrants evaluation as an adjunct to chemotherapy for the treatment of human cholangiocarcinoma.
(n° 271) Protective effect of green tea polyphenols against ultraviolet B-induced damage to HaCaT cells.
Wu LY, Zheng XQ, Lu JL, Liang YR., Hum Cell. 2009 Feb;22(1):18-24, Zhejiang University Tea Research Institute, Hangzhou, Zhejiang Province, China.
Many deleterious effects on the skin have been associated with the ultraviolet B (UVB) portion of the solar spectrum. The role of green tea polyphenols (GTP) in protecting HaCaT cells against the UVB-induced damages was examined. The promotion effect of low level GTP on cell viability was revealed in a dose-dependent manner. High level GTP had a cytotoxic effect. UVB induced destruction of HaCaT cells, including shedding of cell membrane microvilli, degeneration of nucleus and nucleols and changes of mitochondrial size and internal cristae. GTP alleviated the UVB-induced destructive morphological changes in HaCat cells. It is considered that GTP affords protection against the UVB-induced stress via both interacting with UVB-induced reactive oxygen species and attenuating mitochondrion-mediated apoptosis.
(n° 272) Preclinical development of the green tea catechin, epigallocatechin gallate, as an HIV-1 therapy.
Nance CL, Siwak EB, Shearer WT., J Allergy Clin Immunol. 2009 Feb;123(2):459-65, Baylor College of Medicine and Texas Children's Hospital, Houston, Tex, USA.
Previously, we presented evidence that at physiologic concentrations the green tea catechin, epigallocatechin gallate (EGCG), inhibited attachment of HIV-1 glycoprotein 120 to the CD4 molecule on T cells, but the downstream effects of EGCG on HIV-1 infectivity were not determined. Epigallocatechin gallate inhibited HIV-1 infectivity on human CD4(+) T cells and macrophages in a dose-dependent manner. At a physiologic concentration of 6 mumol/L, EGCG significantly inhibited HIV-1 p24 antigen production across a broad spectrum of both HIV-1 clinical isolates and laboratory-adapted subtypes (B [P < .001], C, D, and G [P < .01]). The specificity of the EGCG-induced inhibition was substantiated by the failure of EGCG derivatives lacking galloyl and/or pyrogallol side groups to alter HIV-1 p24 levels. EGCG-induced inhibition of HV-1 infectivity was not a result of cytotoxicity, cell growth inhibition, or apoptosis. We conclude that by preventing the attachment of HIV-1-glycoprotein 120 to the CD4 molecule, EGCG inhibits HIV-1 infectivity. Because this inhibition can be achieved at physiologic concentrations, the natural anti-HIV agent EGCG is a candidate as an alternative therapy in HIV-1 therapy.
(n° 273) Green tea extract prolongs allograft survival as an adjunctive therapy along with low dose cyclosporine A.
Tripathi S, Bruch D, Gatto LA, Kittur DS., J Surg Res. 2009 Jun 1;154(1):85-90. Epub 2008 Jun 2, The State University of New York Upstate Medical University, Syracuse, New York, USA.
The current immunosuppressive drugs are successful in prolonging allograft survival but fail to achieve transplantation tolerance or prevent chronic rejection. Consequently, there is ongoing research to develop novel combinatorial therapies that are more efficacious in prolonging allograft survival as well as induce tolerance toward the transplanted organ. The present study aims to study the efficacy of green tea extract (GTE) in combination with low dose cyclosporine A (CyA) in prolonging allograft survival in mice. Our study demonstrates that GTE in combination with low dose CyA significantly prolongs graft survival as well as increase the production of immunosuppressive cytokine, IL-10. GTE also decreases CyA induced high TGF-beta production, which is incriminated in CyA induced nephrotoxicity. We also observed that GTE inhibits both nonspecific and antigen-specific proliferation of T cells in vitro. These results indicate the potential of GTE as an adjunctive therapy in combination with CyA to prolong allograft survival and to reduce CyA induced nephrotoxicity.
(n° 274) Green tea (-)-epigallocatechin gallate inhibits insulin stimulation of 3T3-L1 preadipocyte mitogenesis via the 67-kDa laminin receptor pathway.
Ku HC, Chang HH, Liu HC, Hsiao CH, Lee MJ, Hu YJ, Hung PF, Liu CW, Kao YH., Am J Physiol Cell Physiol. 2009 Jul;297(1):C121-32. Epub 2009 Jan 28, National Central Univ., Jhong-li, Taiwan.
Insulin and (-)-epigallocatechin gallate (EGCG) have been reported to regulate fat cell mitogenesis and adipogenesis, respectively. This study investigated the pathways involved in EGCG modulation of insulin-stimulated mitogenesis in 3T3-L1 preadipocytes. EGCG inhibited insulin stimulation of preadipocyte proliferation in a dose- and time-dependent manner. EGCG also suppressed insulin-stimulated phosphorylation of the insulin receptor-beta, insulin receptor (IR) substrates 1 and 2 (IRS1 and IRS2), and mitogen-activated protein kinase pathway proteins, RAF1, MEK1/2, and ERK1/2, but not JNK. Furthermore, EGCG inhibited the association of IR with the IRS1 and IRS2 proteins, but not with the IRS4 protein. These data suggest that EGCG selectively affects particular types of IRS and MAPK family members. Generally, EGCG was more effective than epicatechin, epicatechin gallate, and epigallocatechin in modulating insulin-stimulated mitogenic signaling. We identified the EGCG receptor [also known as the 67-kDa laminin receptor (67LR)] in fat cells and found that its expression was sensitive to growth phase, tissue type, and differentiation state. Pretreatment of preadipocytes with 67LR antiserum prevented the effects of EGCG on insulin-stimulated phosphorylation of IRS2, RAF1, and ERK1/2 and insulin-stimulated preadipocyte proliferation (cell number and bromodeoxyuridine incorporation). Moreover, EGCG tended to increase insulin-stimulated associations between the 67LR and IR, IRS1, IRS2, and IRS4 proteins. These data suggest that EGCG mediates anti-insulin signaling in preadipocyte mitogenesis via the 67LR pathway.
(n° 275) In vitro inhibition of Helicobacter pylori urease with non and semi fermented Camellia Sinensis.
Hassani AR, Ordouzadeh N, Ghaemi A, Amirmozafari N, Hamdi K, Nazari R., Indian J Med Microbiol. 2009 Jan-Mar;27(1):30-4, Science and Research Branch of IAU, Tehran, Iran.
Helicobacter pylori is the etiological agent in duodenal and peptic ulcers. The growing problem of antibiotic resistance by the organism demands the search for novel compounds, especially from natural sources. This study was conducted to evaluate the effect of Camellia Sinensis extracts on the urease enzyme that is a major colonization factor for H. pylori. Both extracts had inhibitory effects against H. pylori and urease production. At a concentration of 2.5 mg/ml of nonfermented extract and 3.5 mg/ml of semifermented extract the production of Ure A and Ure B subunits of the urease enzyme were inhibited completely. A concentration of 4 mg/ml of nonfermented and 5.5 mg/ml of semifermented extract were bactericidal for H. pylori. C. Sinensis extracts, especially the nonfermented, could reduce H. pylori population and inhibit urease production at lower concentrations. The superior effect of nonfermented extract is due to its rich polyphenolic compounds and catechin contents.
(n° 276) The potential role of green tea catechins in the prevention of the metabolic syndrome - a review.
Thielecke F, Boschmann M., Phytochemistry. 2009 Jan;70(1):11-24. Epub 2009 Jan 13, Human Nutrition and Health, Basel, CH, Switzerland.
The metabolic syndrome (MetS) represents an emerging health burden for governments and health care providers. Particularly relevant for prevention and early management of MetS are lifestyle conditions including physical activity and the diet. It has been shown that green tea, when consumed on a daily basis, supports health. Many of the beneficial effects of green tea are related to its catechin, particularly (-)-epigallocatechin-3-gallate (EGCG), content. This article provides a comprehensive overview of the human studies addressing the potential benefits of green tea catechins on the MetS. The number of human studies in this field is still limited. However, the majority of human epidemiological and intervention studies demonstrate beneficial effects of green tea or green tea extracts, rich in EGCG on weight management, glucose control and cardiovascular risk factors. The optimal dose has not yet been established. The current body of evidence in humans warrants further attention. In particular, well-controlled long-term human studies would help to fully understand the protective effects of green tea catechins on parameters related to the MetS.
(n° 277) Green tea, black tea consumption and risk of lung cancer: a meta-analysis.
Tang N, Wu Y, Zhou B, Wang B, Yu R., Lung Cancer. 2009 Sep;65(3):274-83. Epub 2009 Jan 6, Shanghai Institute of Pharmaceutical Industry, Zhangjiang Hi-Tech Park, Pudong, Shanghai, China.
Studies investigating the association of green tea and black tea consumption with lung cancer risk have reported inconsistent findings. Summary relative risk (RR) estimates and their corresponding 95% confidence intervals (CIs) were calculated based on random-effects model. Our meta-analysis included 22 studies provided data on consumption of green tea or black tea, or both related to lung cancer risk. For green tea, the summary RR indicated a borderline significant association between highest green tea consumption and reduced risk of lung cancer (RR=0.78, 95% CI=0.61-1.00). Furthermore, an increase in green tea consumption of two cups/day was associated with an 18% decreased risk of developing lung cancer (RR=0.82, 95% CI=0.71-0.96). For black tea, no statistically significant association was observe through the meta-analysis (highest versus non/lowest, RR=0.86, 95% CI=0.70-1.05; an increment of two cups/day, RR=0.82, 95% CI=0.65-1.03). In conclusion, our data suggest that high or an increase in consumption of green tea but not black tea may be related to the reduction of lung cancer risk.
(n° 278) In vitro anti-adhesive activity of green tea extract against pathogen adhesion.
Lee JH, Shim JS, Chung MS, Lim ST, Kim KH., Phytother Res. 2009 Apr;23(4):460-6, School of Life Sciences and Biotechnology, Korea University, Seoul, Korea.
Camellia Sinensis polysaccharide has been reported to possess anti-adhesive activity against pathogens. The present study was designed to investigate whether hot water extracts obtained from green tea leaves might inhibit pathogen adhesion to human or mouse cell lines. Our results suggest that CSI-4 may exert a selective anti-adhesive effect against certain pathogenic bacteria with no adverse effects against beneficial or commensal bacteria.
(n° 279) EGCG inhibits proliferation of cardiac fibroblasts in rats with cardiac hypertrophy.
Sheng R, Gu ZL, Xie ML, Zhou WX, Guo CY., Planta Med. 2009 Feb;75(2):113-20. Epub 2008 Dec 18, Medical School of Suzhou University, Suzhou, PR China.
This study was carried out in order to investigate the effects of epigallocatechin gallate (EGCG) on myocardial fibrosis and cell proliferation in cardiac hypertrophy. The inhibitory effect of EGCG on cell proliferation induced by Ang II was partly blocked by pretreatment with N(omega)-nitro- L-arginine methyl ester hydrochloride. These results suggest that EGCG inhibits the proliferation of cardiac fibroblasts both in vivo and in vitro, thereby preventing myocardial fibrosis in cardiac hypertrophy. EGCG might exert its cardiac protective action through induction of NO production.
(n° 280) Epigallocatechin gallate from green tea (Camellia Sinensis) increases lifespan and stress resistance in Caenorhabditis elegans.
Abbas S, Wink M., Planta Med. 2009 Feb;75(3):216-21. Epub 2008 Dec 11, University of Heidelberg, Heidelberg, Germany.
Epigallocatechin gallate (EGCG) is a major green tea polyphenol with pronounced antioxidative activity. The effects of EGCG on lifespan and stress resistance in wild-type N2 and transgenic strains of Caenorhabditis elegans [ HSP-16.2/GFP, MEV-1(KN1), FEM-1(HC17)] were investigated. The expression of HSP-16.2 (induced by the pro-oxidant juglone) and the intracellular levels of H (2)O (2) were inhibited by EGCG treatment. Daily administration of 220 muM EGCG increased the mean lifespan by 10.14 % and 14.27 % in N2 and FEM-1(HC17) strains, respectively, and 55 muM EGCG increased the mean lifespan in MEV-1(KN1) by 16.11 %. The survival rate was also increased under lethal oxidative stress by 65.05 %. These findings suggest that the increased mean lifespan and stress resistance in C. ELEGANS apparently depend, among other factors, on the antioxidant properties of EGCG.
(n° 281) Extract of green tea leaves partially attenuates streptozotocin-induced changes in antioxidant status and gastrointestinal functioning in rats.
Juśkiewicz J, Zduńczyk Z, Jurgoński A, Brzuzan Ł, Godycka-Kłos I, Zary-Sikorska E., Nutr Res. 2008 May;28(5):343-9, Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Division of Food Science, Olsztyn, Poland.
Rats with severe streptozotocin (STZ)-induced diabetes were subjected to dietary green tea extract supplementation at 2 doses (0.01% and 0.2%; GTL and GTH groups, respectively) to evaluate their effects on antioxidant, gastrointestinal, and renal parameters of experimental animals. The lower dietary supplementation reflects daily consumption of 3 cups of green tea for an average adult weighing 70 kg. Supplementation of a diet with green tea extract had no influence on elevated food intake, body weight loss, increased glucose concentration, or declined antioxidant capacity of water-soluble substances in plasma in the diabetic rats. In cases of intestinal maltase activity, attenuation of liver and kidney hypertrophy, triacylglycerol concentration, and aspartate aminotransferase activity in the serum, both dietary treatments normalized metabolic disorders caused by STZ injection to a similar extent. Unlike the GTL group, the GTH treatment significantly ameliorated development of diabetes-induced abnormal values for small intestinal saccharase and lactase activities, renal microalbuminuria, thiobarbituric acid-reactive substance content in kidney tissue, as well as total antioxidant status in the serum of rats. The GTH group was also characterized by higher antioxidant capacity of lipid-soluble substances in plasma and superoxide dismutase activity in the serum. Although the higher dose of green tea extract did not completely protect against STZ-induced hyperglycemia and oxidative stress in experimental rats, this study suggests that green tea extract ingested at high amounts may prove to be a useful therapeutic option in the reversal of diabetic dysfunction.
(n° 282) Caging a Beast in the Inflammation Arena: Use of Chinese Medicinal Herbs to Inhibit a Late Mediator of Lethal Sepsis, HMGB1.
Zhu S, Li W, Li J, Sama AE, Wang H., Int J Clin Exp Med. 2008;1(1):64-75. Epub 2008 Jan 20.
Sepsis refers to a systemic inflammatory response syndrome resulting from a microbial infection, which kills > 225,000 people annually in the U.S. alone. The high mortality of sepsis is partly mediated by bacterial endotoxin, which stimulates macrophages/monocytes to sequentially release early (e.g., TNF) and late (e.g., HMGB1) pro-inflammatory cytokines. Although early proinflammatory cytokines may be protective against infection, excessive accumulation of late-acting proinflammatory mediators (such as HMGB1) may sustain a potentially injurious inflammatory response. Agents capable of inhibiting HMGB1 activities (e.g., neutralizing antibodies) or release [e.g., Chinese herbs, Danggui (Angelica Sinensis), Danshen (Salvia miltiorrhiza) and Green tea (Camellia Sinensis)] rescue mice from lethal sepsis even when given 24 hours after onset of the disease. Here we review emerging evidence that support a critical role for extracellular HMGB1 as a late mediator of lethal sepsis, and several commonly used Chinese herbs (Danggui, Danshen and Green tea) as potential HMGB1- targeting therapeutic agents in experimental sepsis.
(n° 283) Significant longevity-extending effects of EGCG on Caenorhabditis elegans under stress.
Zhang L, Jie G, Zhang J, Zhao B., Free Radic Biol Med. 2009 Feb 1;46(3):414-21. Epub 2008 Nov 5, Chinese Academy of Sciences, Beijing, People's Republic of China.
Epigallocatechin gallate (EGCG), a main active ingredient of green tea, is believed to be beneficial in association with anticarcinogenesis, antiobesity, and blood pressure reduction. Here we report that EGCG extended Caenorhabditis elegans longevity under stress. Quantitative real-time PCR results showed that the up-regulation of aging-associated genes such as daf-16, sod-3, and skn-1 could also contribute to the stress resistance attributed to EGCG. As the death rate of a population is closely related to the mortality caused by external stress, it could be concluded that the survival-enhancing effects of EGCG on C. elegans under stress are very important for antiaging research.
(n° 284) Inhibitory effect of tea polyphenols on hepatic preneoplastic foci in Wistar rats.
Srivastava S, Singh M, Roy P, Prasad S, George J, Shukla Y., Invest New Drugs. 2009 Dec;27(6):526-33. doi: 10.1007/s10637-008-9204-6. Epub 2008 Dec 5, Indian Institute of Toxicology Research, Mahatma Gandhi Marg, Lucknow, India.
Tea (Camellia Sinensis) is one of the most widely used beverages worldwide and tea consumption has been shown to have an inverse correlation to the incidence of human cancers in epidemiological and experimental studies. In the present study, the protective effects of green tea polyphenols (GTP) and black tea polyphenols (BTP) in Wistar rats were assessed by medium-term bioassay, using altered hepatic foci (AHF) as end point. Tea polyphenol supplementation resulted in a significant protection against AHF induction in Wistar rats. In addition, levels of the positive biomarkers: gamma-glutamyl transpeptidase and glutathione-S-transferase (placental form) were reduced with GTP and BTP supplementation. Levels of the negative biomarkers adenosine triphosphatase and glucose-6-phosphatase were also restored by GTP and BTP administration. Thus, these results show the hepatoprotective effects of GTP and BTP against DEN- and 2-AAF-induced AHF development.
(n° 285) Daily consumption of an aqueous green tea extract supplement does not impair liver function or alter cardiovascular disease risk biomarkers in healthy men.
Frank J, George TW, Lodge JK, Rodriguez-Mateos AM, Spencer JP, Minihane AM, Rimbach G., J Nutr. 2009 Jan;139(1):58-62. Epub 2008 Dec 3, Christian-Albrechts-University, Kiel, Germany.
Regular consumption of green tea polyphenols (GTP) is thought to reduce the risk of cardiovascular disease (CVD) but has also been associated with liver toxicity. The present trial aimed to assess the safety and potential CVD health beneficial effects of daily GTP consumption. After treatment, the ratio of total:HDL cholesterol was significantly reduced in participants taking GTP capsules compared with baseline. Endothelial-dependent and -independent vascular reactivity did not significantly differ between treatments. In conclusion, the present data suggests that the daily consumption of high doses of GTP by healthy men for 3 wk is safe but without effects on CVD risk biomarkers other than the total:HDL cholesterol ratio.
(n° 286) Green tea (Camellia Sinensis) attenuates nephropathy by downregulating Nox4 NADPH oxidase in diabetic spontaneously hypertensive rats.
Ribaldo PD, Souza DS, Biswas SK, Block K, Lopes de Faria JM, Lopes de Faria JB., J Nutr. 2009 Jan;139(1):96-100. Epub 2008 Dec 3, State University of Campinas, Campinas, SP, Brazil.
Green tea (GT), through its antioxidant properties, may be useful to treat or prevent human diseases. Because several lines of evidence suggest that oxidative stress contributes to the pathogenesis of diabetic nephropathy, we tested the hypothesis that GT prevents diabetes and hypertension-related renal oxidative stress, attenuating renal injury. Spontaneously hypertensive rats (SHR) with streptozotocin-induced diabetes and nondiabetic SHR were treated daily with tap water or freshly prepared GT (13.3 g/L). The 8-OHdG and NADPH oxidase-dependent superoxide generation were significantly less in rats treated with GT. Nitrotyrosine and Nox4 expression were significantly less in diabetic rats that received GT (DGT) than in DW. Likewise, the indices of renal injury, albuminuria, and renal expression of collagen IV were significantly greater in DW than in CW. These differences were significantly less in DGT than in DW. GT reestablished the redox state and reduced the indicators of nephropathy without altering glycemia and blood pressure levels in diabetic SHR. These findings suggest that the consumption of GT may ameliorate nephropathy in diabetic hypertensive patients.
(n° 287) Antilipogenic effect of green tea extract in C57BL/6J-Lep ob/ob mice.
Kim HJ, Jeon SM, Lee MK, Jung UJ, Shin SK, Choi MS., Phytother Res. 2009 Apr;23(4):467-71, Kyungpook National University, Daegu, Korea.
The objective of this study was to determine the effects of green tea extract (GTE) on lipid metabolism in obese animal models. Male C57BL/6J-Lep ob/ob mice were divided into control and GTE (0.05 g/100 g diet) groups, which were fed a high-fat (20 g/100 g diet) diet for 12 weeks. The current results showed that supplementation of green tea extract is beneficial for antiobesity by the suppression of lipogenesis via regulation of related enzyme activities in hepatic and adipose tissue.
(n° 288) Chemoprotective properties of rooibos (Aspalathus linearis), honeybush (Cyclopia intermedia) herbal and green and black
(Camellia Sinensis) teas against cancer promotion induced by fumonisin B1 in rat liver.
Marnewick JL, van der Westhuizen FH, Joubert E, Swanevelder S, Swart P, Gelderblom WC., Food Chem Toxicol. 2009 Jan;47(1):220-9. Epub 2008 Nov 7, Cape Peninsula University of Technology, Cape Town, South Africa.
The chemoprotective properties of unfermented and fermented rooibos (Aspalathus linearis) and honeybush (Cyclopia intermedia) herbal teas, and green and black teas (Camellia Sinensis) were investigated against fumonisin B1 (FB1) promotion in rat liver utilizing diethylnitrosamine (DEN) as cancer initiator. The teas exhibited varying effects on FB1-induced changes in the activities of catalase, glutathione peroxidase (GPx) glutathione reductase (GR) as well as the glutathione (GSH) status. Unfermented rooibos and honeybush significantly (P<0.05) to marginally (P<0.1) reduced the total number of foci (>10microm), respectively, while all the teas reduced the relative amount of the larger foci. Fermentation seems to reduce the protective effect of the herbal teas. Differences in the major polyphenolic components and certain FB1/polyphenolic/tissue interactions may explain the varying effects of the different teas on the oxidative parameters, hepatotoxic effects and cancer promotion in rat liver.
(n° 289) An aqueous extract of green tea Camellia Sinensis increases expression of Th1 cell-specific anti-asthmatic markers.
Heo JC, Rho JR, Kim TH, Kim SY, Lee SH., Int J Mol Med. 2008 Dec;22(6):763-7, Kyungpook National University, Daegu, Korea.
The present study provides evidence of the anti-asthmatic signaling activity of an aqueous fraction of green tea using specific in vitro and in vivo assays in an ovalbumin-induced asthmatic model. The aqueous extract of Camellia Sinensis exhibited potent anti-asthmatic activity by increasing the expression level of tumor necrosis factor-beta and interferon-gamma and decreasing the expression of anti-asthmatic cytokines in the lung. Together, these results indicate that the aqueous fraction of Camellia Sinensis is effective in alleviating asthmatic symptoms by increasing the expression of Th1 cell-specific anti-asthmatic biomarkers.
(n° 290) Long-term caffeine consumption reverses tumor-induced suppression of the innate immune response in adult mice.
Mandal A, Poddar MK., Planta Med. 2008 Dec;74(15):1779-84. Epub 2008 Nov 18, University of Calcutta, Kolkata, India.
Caffeine (1,3,7-trimethylxanthine), the active principle alkaloid of coffee ( Coffea arabica) and tea ( Camellia Sinensis) possesses a restraining effect on tumor-induced suppression of the specific immune response in adult mice. The present study deals with the effect of long-term consumption of caffeine in the development of Ehrlich ascites carcinoma (EAC) cells in adult Swiss female mice, in relation to the innate immune response and tumor growth. Although the consumption of caffeine alone for more than 12 consecutive days did not affect the innate immune response parameters, continuation of its treatment following intraperitoneal EAC cell inoculation not only reduced the IN VIVO tumor growth but also reduced/restored the EAC cell-induced suppression of the innate immune response. These results suggest that caffeine may inhibit IN VIVO tumor growth through reduction of the cancer cell-induced suppression of the innate immune response. CNS:central nervous system EAC:Ehrlich ascites carcinoma ESR:erythrocyte sedimentation rate GABA:gamma-aminobutyric acid Hb:hemoglobin HPA:hypothalamic-pituitary-adrenal HPG:hypothalamic-pituitary-gonadal PCV:packed cell volume RBC:red blood cell WBC:white blood cell.
(n° 291) Antioxidative and anti-carcinogenic activities of tea polyphenols.
Yang CS, Lambert JD, Sang S., Arch Toxicol. 2009 Jan;83(1):11-21. Epub 2008 Nov 12, The State University of New Jersey, Piscataway, NJ, USA.
Tea (Camellia Sinensis, Theaceace), a popular beverage consumed world-wide, has been studied for its preventive effects against cancer as well as cardiovascular, neurodegenerative, and other diseases. Most of the proposed beneficial effects have been attributed to the polyphenolic compounds in tea, but the nature of these activities and the molecular mechanisms of their actions remain unclear. Tea polyphenols are known to be strong antioxidants. Prevention of oxidative stress, modulation of carcinogen metabolism, and prevention of DNA damage have been suggested as possible cancer preventive mechanisms for tea and tea polyphenols. In this chapter, we discuss these topics in the light of biotransformation and bioavailability of tea polyphenols. We also review the preventive effects of tea polyphenols in animal models of carcinogenesis and some of the possible post-initiation mechanisms of action. Finally, we discuss the effects of tea consumption on cancer risk in humans. It is our aim to raise some of the unanswered questions regarding cancer prevention by tea and to stimulate further research in this area.
(n° 292) Black tea polyphenols modulate xenobiotic-metabolizing enzymes, oxidative stress and adduct formation in a rat hepatocarcino-genesis model.
Murugan RS, Uchida K, Hara Y, Nagini S., Free Radic Res. 2008 Oct;42(10):873-84, Annamalai University, Tamil Nadu, India.
The present study was designed to investigate the modulatory effects of black tea polyphenols (Polyphenon-B) on phase I and phase II xenobiotic-metabolizing enzymes and oxidative stress in a rat model of hepatocellular carcinoma (HCC). Dietary administration of Polyphenon-B effectively suppressed DAB-induced hepatocarcinogenesis, as evidenced by reduced preneoplastic and neoplastic lesions, modulation of xenobiotic-metabolizing enzymes and amelioration of oxidative stress. Thus, it can be concluded that Polyphenon-B acts as an effective chemopreventive agent by modulating xenobiotic-metabolizing enzymes and mitigating oxidative stress in an in vivo model of hepatocarcinogenesis.
(n° 293) Differential growth suppression of human melanoma cells by tea (Camellia Sinensis) epicatechins (ECG, EGC and EGCG).
Ravindranath MH, Ramasamy V, Moon S, Ruiz C, Muthugounder S., Evid Based Complement Alternat Med. 2009 Dec;6(4):523-30. Epub 2007 Oct 22, John Wayne Cancer Institute, Santa Monica, CA, USA.
We previously reported that catechins of green tea have different antiproliferative effects on cell lines derived from gender-dependent cancers; epicatechin 3-gallate (ECG) had the strongest inhibitory effect. In the present study, we examined the effects of epigallocatechin (EGC), epicatechin-gallate (ECG) and EGC 3-gallate (EGCG) on the viability, density, doubling time and cycle number of cell lines derived from melanoma metastasized to lymph nodes (MB-1133 and SE-0154) or distant organs (CH-0356, JK-0346, SA-1171, GE-0208, NS-1176 and LF-0023). When compared with EGC, the cytotoxic effect (% dead cell counts) and the suppression of the growth (change in cell number) of all melanoma cell lines tested were pronounced with EGCG. This investigation validates the hypothesis that anticancer action of the various catechins may vary with the type of malignancy and provides a model for tumor cell heterogeneity based on susceptibility and resistance of tumor cells to different green tea catechins. Therefore, this information is critical for undertaking chemopreventive or chemotherapeutic trials against melanoma and gender-based cancers.
(n° 294) Green tea (Camellia Sinensis) and cancer prevention: a systematic review of randomized trials and epidemiological studies.
Liu J, Xing J, Fei Y., Chin Med. 2008 Oct 22;3:12, Beijing University of Chinese Medicine, Beijing, PR China. Jianping.Liu@fagmed.uit.no
Green tea is one of the most popular beverages worldwide. This review summarizes the beneficial effects of green tea on cancer prevention. Forty-three epidemiological studies, four randomized trials and one meta-analysis were identified. The overall quality of these studies was evaluated as good or moderate. While some evidence suggests that green tea has beneficial effects on gastrointestinal cancers, the findings are not consistent. Green tea may have beneficial effects on cancer prevention. Further studies such as large and long term cohort studies and clinical trials are warranted.
(n° 295) Green tea protects rats against autoimmune arthritis by modulating disease-related immune events.
Kim HR, Rajaiah R, Wu QL, Satpute SR, Tan MT, Simon JE, Berman BM, Moudgil KD., J Nutr. 2008 Nov;138(11):2111-6, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
Green tea, a product of the dried leaves of Camellia Sinensis, is the most widely consumed beverage in the world. The polyphenolic compounds from green tea (PGT) possess antiinflammatory properties. We investigated whether PGT can afford protection against autoimmune arthritis and also examined the immunological basis of this effect using the rat adjuvant arthritis (AA) model of human rheumatoid arthritis (RA). Feeding 8 g/L PGT to Lewis rats for 9 d significantly reduced the severity of arthritis compared with the water-fed controls. Interestingly, PGT-fed rats had a lower concentration of the proinflammatory cytokine interleukin (IL)-17 but a greater concentration of the immunoregulatory cytokine IL-10 than controls. PGT feeding also suppressed the anti-Bhsp65 antibody response. Thus, green tea induced changes in arthritis-related immune responses. We suggest further systematic exploration of dietary supplementation with PGT as an adjunct nutritional strategy for the management of RA.
(n° 296) Standardized capsule of Camellia Sinensis lowers cardiovascular risk factors in a randomized, double-blind, placebo-controlled study.
Nantz MP, Rowe CA, Bukowski JF, Percival SS., Nutrition. 2009 Feb;25(2):147-54. Epub 2008 Oct 9, University of Florida, Gainesville, FL, USA.
Previous studies examining the effect of tea drinking on cardiovascular health have produced mixed results due to their observational nature and qualitatively and quantitatively imprecise definitions of active tea components. The objective of this study was to determine if a standardized and defined decaffeinated green tea (Camellia Sinensis) product lowers blood pressure, serum lipids, oxidative stress, and markers of chronic inflammation. CSC was effective for decreasing, in as quickly as 3 wk, blood pressure, LDL cholesterol, oxidative stress, and a marker of chronic inflammation, all independent cardiovascular risk factors.
(n° 297) Epigallocatechin gallate promotes GLUT4 translocation in skeletal muscle.
Ueda M, Nishiumi S, Nagayasu H, Fukuda I, Yoshida K, Ashida H., Biochem Biophys Res Commun. 2008 Dec 5;377(1):286-90. Epub 2008 Oct 7, Kobe University, Kobe, Japan.
In this study, we investigated whether epigallocatechin gallate (EGCg) affects glucose uptake activity and the translocation of insulin-sensitive glucose transporter (GLUT) 4 in skeletal muscle. A single oral administration of EGCg at 75 mg/kg body weight promoted GLUT4 translocation in skeletal muscle of rats. EGCg significantly increased glucose uptake accompanying GLUT4 translocation in L6 myotubes at 1 nM. The translocation of GLUT4 was also observed both in skeletal muscle of mice and rats ex vivo and in insulin-resistant L6 myotubes. Wortmannin, an inhibitor of phosphatidylinositol 3'-kinase, inhibited both EGCg- and insulin-increased glucose uptakes, while genistein, an inhibitor of tyrosine kinase, failed to inhibit the EGCg-increased uptake. Therefore, EGCg may improve hyperglycemia by promoting GLUT4 translocation in skeletal muscle with partially different mechanism from insulin.
(n° 298) A nutrient mixture suppresses carbon tetrachloride-induced acute hepatic toxicity in ICR mice.
Roomi M, Kalinovsky T, Roomi NW, Ivanov V, Rath M, Niedzwiecki A., Hum Exp Toxicol. 2008 Jul;27(7):559-66, Dr Rath Research Institute, Santa Clara, California, USA.
We examined the effect of a nutrient mixture (NM) that contains lysine, proline, ascorbic acid, and green tea extract in mice treated with carbon tetrachloride (CCl4), a model of liver injury in which free radical, oxidative stress, and cytokine production are closely linked. Seven-week-old male Imprinting Control Region (ICR) mice were divided into four groups (A-D) of five animals each. Groups A and C mice were fed a regular diet for 2 weeks, whereas groups B and D mice were supplemented with 0.5% NM (w/w) during that period. Groups A and B received corn oil i.p., whereas groups C and D received CCl4 (25 microL/kg, in corn oil, i.p.). All animals were killed 24 h after CCl4 administration, serum was collected to assess liver and kidney functions, and livers and kidneys were excised for histology. Mean serum aspartate aminotransferase and alanine aminotransferase were comparable in groups A and B, increased markedly in group C, and significantly lowered in group D compared with group C. CCl4 had no significant effect on renal markers (blood urea nitrogen [BUN], creatinine, and BUN/creatinine ratio). CCl4 administration caused an intense degree of liver necrosis that was less severe in the NM fed group D. These results indicate that NM could be a useful supplement in preventing acute chemical-induced liver toxicity.
(n° 299) Volatile components of Camellia Sinensis inhibit growth and biofilm formation of oral streptococci in vitro.
Hassani AS, Amirmozafari N, Ordouzadeh N, Hamdi K, Nazari R, Ghaemi A., Pak J Biol Sci. 2008 May 15;11(10):1336-41, Department of Microbiology, Tehran, Iran.
This study aimed to evaluate the efficacy of semi fermented and non fermented Camellia Sinensis extracts (Black and Green tea) and comparison between them against Streptococcus mutans ATCC 25175, S. mitis ATCC 9811 and S. sanguis ATCC 10556 that are responsible for dental caries and bacteremias following dental manipulations. Minimum inhibitory concentrations of both tea extracts were assessed by Well diffusion and Broth dilution methods and examination of cell adherence (Biofilm inhibitory concentrations) was observed on glass slides under phase contrast microscope and colony counts from glass beads. Concentration of 1 mg mL(-1) of semi fermented tea extract was completely biofilm inhibitor but biofilm formation by these bacteria was seen 7 days after treatment with 1 mg mL(-1) of non fermented Camellia Sinensis on glass beads and BIC for oral streptococci treated with this extract was 1.5, 2.5 mg mL(-1) of semi fermented and 3 mg mL(-1) of non fermented extracts had bactericidal effect on these bacteria. Semi fermented and non fermented Camellia Sinensis extracts were able to prevent growth of oral streptococci. Therefore dental caries significantly reduce and the efficiency of semi fermented tea was higher due to rich content of volatile components rather than non fermented extracts.
(n° 300) Green tea reduces LDL oxidability and improves vascular function.
Tinahones FJ, Rubio MA, Garrido-Sánchez L, Ruiz C, Gordillo E, Cabrerizo L, Cardona F., J Am Coll Nutr. 2008 Apr;27(2):209-13, Hospital Clinico Virgen de la Victoria de Málaga, Spain.
Several different epidemiological studies have examined the association between the consumption of tea and coronary heart disease. Some, though not all, support the view that tea or flavonoids reduce the risk of cardiovascular heart disease. The aim of this study was to determine the short-to medium-term effect of a green tea extract on vascular function and lipid peroxidation as compared with placebo.The mean diameter of the brachial artery following the post-compression hyperaemia phase rose significantly (p < 0.0001) after treatment with green tea extract. Flow-mediated brachial artery vasodilation ranged from 5.68% for the placebo phase to 11.98% after the green tea extract (p = 0.02). The consumption of green tea extract was associated with a significant 37.4% reduction in the concentration of oxidized LDL (TBARS) (p = 0.017). The levels of anti-oxidized LDL IgM antibodies fell significantly after treatment (p = 0.002). This study found that consumption of green tea extract by women for five weeks produced modifications in vascular function and an important decrease in serum oxidizability.