(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. In conclusion, green tea, Rooibos and enalaprilat seem to inhibit ACE activity using a mixed inhibitor mechanism.
(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. A daily TPP intake threshold of 7 mg/100 g body weight existed below where no inhibition of papilloma development was observed. 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° 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). These extracts were incorporated into the preliminary developed stable gel base with good preference. The gingko formulation was found to be more stable than the formula containing a mixture of tea and rooibos and the soybean formula. Clinical efficacies of the ginkgo formula and the formula containing a mixture of tea and rooibos were compared following 28 days of application. 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. Enzyme linked immunosorbent assays were used to screen spent culture medium for Interleukin-6, Interleukin-10 and Interferon gamma as biomarkers for inflammation, humoral immunity, and cell mediated immunity, respectively. 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° 301) Rooibos (Aspalathus linearis) offers cardiac protection against ischaemia/reperfusion in the isolated perfused rat heart.
Pantsi WG, Marnewick JL, Esterhuyse AJ, Rautenbach F, van Rooyen J., Phytomedicine. 2011 Nov 15;18(14):1220-8. Epub 2011 Oct 5., Cape Peninsula University of Technology, Bellville, South Africa.
Rooibos, a unique South African herbal tea, is known to be an important source of unique polyphenolic compounds. In the present study we have quantified the main polyphenolic compounds in both fermented/traditional and unfermented/"green" rooibos (Aspalathus linearis) and evaluated its cardioprotective effects against ischaemia/reperfusion injury. The results clearly demonstrate the cardio-protective properties of aqueous rooibos extracts via the inhibition of apoptosis which can possibly be related to the flavonol content of this unique South African herbal tea.
(n° 302) Identification of phenolic compounds in aqueous and ethanolic rooibos extracts (Aspalathus linearis) by HPLC-ESI-MS (TOF/IT).
Iswaldi I, Arráez-Román D, Rodríguez-Medina I, Beltrán-Debón R, Joven J, Segura-Carretero A, Fernández-Gutiérrez A., Anal Bioanal Chem. 2011 Jul;400(10):3643-54. Epub 2011 Apr 21., University of Granada, Granada, Spain.
Rooibos (Aspalathus linearis) is a rich source of polyphenols and used to make a mild-tasting tea containing no caffeine, is low in tannins compared to green or black teas, and has antioxidant and antimutagenic/antitumoral properties. In vivo results show that rooibos has beneficial effects upon the lipid profile by decreasing serum triglycerides and cholesterol.
(n° 303) Continuous administration of polyphenols from aqueous rooibos (Aspalathus linearis) extract ameliorates dietary-induced metabolic disturbances in hyperlipidemic mice.
Beltrán-Debón R, Rull A, Rodríguez-Sanabria F, Iswaldi I, Herranz-López M, Aragonès G, Camps J, Alonso-Villaverde C, Menéndez JA, Micol V, Segura-Carretero A, Joven J. , Phytomedicine. 2011 Mar 15;18(5):414-24. Epub 2011 Jan 5., Universitat Rovira i Virgili, Reus, Spain.
The incidence of obesity and related metabolic diseases is increasing globally. Current medical treatments often fail to halt the progress of such disturbances, and plant-derived polyphenols are increasingly being investigated as a possible way to provide safe and effective complementary therapy. Rooibos (Aspalathus linearis) is a rich source of polyphenols without caloric and/or stimulant components. We have tentatively characterized 25 phenolic compounds in rooibos extract and studied the effects of continuous aqueous rooibos extract consumption in mice. Our findings suggest that adding polyphenols to the daily diet is likely to help in the overall management of metabolic diseases.
(n° 304) Effects of rooibos (Aspalathus linearis) on oxidative stress and biochemical parameters in adults at risk for cardiovascular disease.
Marnewick JL, Rautenbach F, Venter I, Neethling H, Blackhurst DM, Wolmarans P, Macharia M., J Ethnopharmacol. 2011 Jan 7;133(1):46-52. Epub 2010 Sep 15., Cape Peninsula University of Technology, Bellville, South Africa.
In South Africa, the plant Aspalathus linearis (Brum.f) Dahlg. (Fabaceae) is traditionally used as a "tea" referred to as rooibos or redbush. This plant has been listed as a medicinal plant based mostly on anecdotal evidence. Despite a long history of traditional use in South Africa, very little scientific data are available from controlled clinical trials confirming its popular use. The aim of the present study was to investigate the effect of rooibos on biochemical and oxidative stress parameters in adults at risk for cardiovascular disease. The lipid profiles showed that rooibos consumption, compared with the control values, significantly decreased serum LDL-cholesterol (4.6±1.3 mmol/L vs. 3.9±0.7 mmol/L) and triacylglycerols (1.7±0.8 mmol/L vs. 1.2±0.7 mmol/L), while HDL-cholesterol (0.9±0.1 mmol/L vs. 1.2±0.2 mmol/L) was significantly increased. Confirming its popular use, consumption of fermented, traditional rooibos significantly improved the lipid profile as well as redox status, both relevant to heart disease, in adults at risk for developing cardiovascular disease.
(n° 305) Oxidative stress and Alzheimer's disease: dietary polyphenols as potential therapeutic agents.
Darvesh AS, Carroll RT, Bishayee A, Geldenhuys WJ, Van der Schyf CJ., Expert Rev Neurother. 2010 May;10(5):729-45., Northeastern Ohio University, Rootstown, USA.
Oxidative stress has been strongly implicated in the pathophysiology of neurodegenerative disorders such as Alzheimer's disease (AD). In recent years, antioxidants - especially those of dietary origin - have been suggested as possible agents useful for the prevention and treatment of AD. This article reviews the role of oxidative stress and the contribution of free radicals in the development of AD, and also discusses the use of antioxidants as a therapeutic strategy in the amelioration of this illness. The antioxidant potential of polyphenolic compounds obtained from dietary sources, such as anthocyanins from berries, catechins and theaflavins from tea, curcumin from turmeric, resveratrol from grapes and peanuts, the dihydrochalcones aspalathin and nothofagin from rooibos and the xanthone mangiferin from honeybush, are discussed in this review. The neuroprotective effects of these phytochemicals in preclinical models of AD are highlighted. Finally, innovative concepts, novel hypotheses, current challenges and future directions in the use of dietary polyphenols for the treatment of AD are discussed.
(n° 306) Effects of green tea, black tea and Rooibos tea on angiotensin-converting enzyme and nitric oxide in healthy volunteers.
Persson IA, Persson K, Hägg S, Andersson RG., Public Health Nutr. 2010 May;13(5):730-7. Epub 2010 Feb 10., Linköping University, Linköping, Sweden.
Tea has been reported to reduce cardiovascular mortality, but the underlying mechanisms are largely unknown. The aim of the current project was to investigate the effect of green tea (Japanese Sencha), black tea (Indian Assam B.O.P.) and Rooibos tea (South Africa) on angiotensin-converting enzyme (ACE) and nitric oxide (NO). Seventeen healthy volunteers received a single oral dose of 400 ml green tea, black tea or Rooibos tea in a randomized, three-phase, crossover study. These results suggest that green tea and Rooibos tea may have cardiovascular effects through inhibition of ACE activity.
(n° 307) In vitro hepatic biotransformation of aspalathin and nothofagin, dihydrochalcones of rooibos (Aspalathus linearis), and assessment of metabolite antioxidant activity.
van der Merwe JD, Joubert E, Manley M, de Beer D, Malherbe CJ, Gelderblom WC., J Agric Food Chem. 2010 Feb 24;58(4):2214-20., Stellenbosch University, South Africa.
Aspalathin (2',3,4,4',6'-pentahydroxy-3'-C-beta-d-glucopyranosyldihydrochalcone) is the major flavonoid present in the South African herbal tea rooibos. The balance between conjugated and unconjugated forms of aspalathin could have important implications regarding its role in affecting oxidative status in intra- and extracellular environments in vivo.
(n° 308) Antioxidant activity of the dihydrochalcones Aspalathin and Nothofagin and their corresponding flavones in relation to other Rooibos ( Aspalathus linearis ) Flavonoids, Epigallocatechin Gallate, and Trolox.
Snijman PW, Joubert E, Ferreira D, Li XC, Ding Y, Green IR, Gelderblom WC., J Agric Food Chem. 2009 Aug 12;57(15):6678-84., Stellenbosch University, Matieland , South Africa.
The antioxidant activity of rooibos flavonoids, including the dihydrochalcones aspalathin and nothofagin and their corresponding flavone glycosides, was evaluated using the ABTS radical cation, metal chelating, and Fe(II)-induced microsomal lipid peroxidation assays. Epigallocatechin gallate (EGCG) and Trolox were used as reference standards. Optimized geometric conformers of aspalathin and nothofagin, in addition to calculated physicochemical properties, were considered to explain interaction with the microsomal membrane structure and thus relative potency of the dihydrochalcones. The most potent radical scavengers were aspalathin (IC50 = 3.33 microM) and EGCG (IC50 = 3.46 microM), followed by quercetin (IC50 = 3.60 microM) and nothofagin (IC50 = 4.04 microM). The least effective radical scavengers were isovitexin (IC50 = 1224 microM) and vitexin (IC50 > 2131 microM). Quercetin (IC50 = 17.5 microM) and EGCG (IC50 = 22.3 microM) were the most effective inhibitors of lipid peroxidation. Aspalathin (IC50 = 50.2 microM) and catechin (IC50 = 53.3 microM) displayed similar potencies. Nothofagin (IC50 = 1388 microM) was almost as ineffective as its flavone glycoside analogues.
(n° 309) Bioavailability of C-linked dihydrochalcone and flavanone glucosides in humans following ingestion of unfermented and fermented rooibos teas.
Stalmach A, Mullen W, Pecorari M, Serafini M, Crozier A., J Agric Food Chem. 2009 Aug 12;57(15):7104-11., University of Glasgow, Glasgow , United Kingdom.
High-performance liquid chromatography-mass spectrometry (HPLC-MS(n)) detected aspalathin and nothofagin, C-glycosides of apigenin and luteolin, and four eriodictyol-C-glycoside isomers in unfermented and fermented rooibos teas. The fermented drink contained 10-fold higher levels of aspalathin and nothofagin and a 4-fold lower eriodictyol-C-glycoside content than the fermented tea. . Most of the aspalathin metabolites were excreted within 5 h of tea consumption, suggesting absorption in the small intestine. Urinary excretion of the eriodictyol-O-sulfate occurred mainly during the 5-12 h collection period, indicative of absorption in the large intestine. Despite exhaustive searches, no flavonoid metabolites were detected in plasma.
(n° 310) Phenolic contribution of South African herbal teas to a healthy diet.
Joubert E, Gelderblom WC, De Beer D., Nat Prod Commun. 2009 May;4(5):701-18., Agricultural Research Council, Stellenbosch, South Africa
South African herbal teas, rooibos and honeybush, are increasingly enjoyed as healthy alternatives to Camellia sinensis teas. They contribute to the diet with bioactive phytochemicals not commonly found in foods. Major compounds of rooibos are the unique dihydrochalcone, aspalathin, and its flavone isomers, orientin and isoorientin. Honeybush contributes the xanthones, mangiferin and isomangiferin and the flavanones, eriocitrin, narirutin and hesperidin. All these compounds are either C-glucosides or O-rhamnoglucosides, which are poorly absorbed.
(n° 311) Structure-antioxidant relationship of flavonoids from fermented rooibos.
Krafczyk N, Woyand F, Glomb MA., Mol Nutr Food Res. 2009 May;53(5):635-42., Martin Luther University, Halle-Wittenberg, Germany.
Rooibos tea (Aspalathus linearis) contains different bioactive phenolic compounds such as dihydrochalcones, flavonols, flavanones, flavones, and flavanols. Flavonoids isolated from rooibos were subjected to different in vitro assays: Trolox equivalent antioxidant activity, LDL oxidation and Fremy's salt assays to determine the total antioxidant activity (TAA).
(n° 312) 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° 313) Does rooibos tea (Aspalathus linearis) support regeneration of rat liver after intoxication by carbon tetrachloride?
Ulicná O, Vancová O, Waczulíková I, Bozek P, Janega P, Babál P, Lísková S, Greksák M., Gen Physiol Biophys. 2008 Sep;27(3):179-86., Comenius University, Bratislava, Slovakia.
This study evaluates the effect of rooibos tea (RT, Aspalathus linearis) on biochemical and histological parameters during rat liver regeneration after intoxication by carbon tetrachloride (CCl4). From the 10th week, when the administration of CCl4 was terminated, the liver tissue began to regenerate. We conclude that RT can be recommended not only for the prevention but also as a co-adjuvant for the therapy of liver diseases.
(n° 314) Transport of aspalathin, a Rooibos tea flavonoid, across the skin and intestinal epithelium.
Huang M, du Plessis J, du Preez J, Hamman J, Viljoen A., Phytother Res. 2008 May;22(5):699-704., University of the Witwatersrand, Johannesburg, South Africa.
Since Rooibos tea contains high levels of flavonoid antioxidants with potential health benefits when taken orally or applied topically, the quantity of the antioxidants crossing the physiological barriers is of scientific, clinical and commercial importance. This study investigated the in vitro transport of aspalathin, a unique flavonoid constituent of Rooibos tea, across intestinal epithelial cells and the human skin. The transport studies were conducted for both pure aspalathin solutions and extracts from unfermented (or green) Rooibos (Aspalathus linearis) aerial plant material across human abdominal skin in vertical Franz diffusion cells and Caco-2 cell monolayers in Transwell 6-well plates. The results obtained from the percutaneous permeation studies demonstrated that only 0.01% of the initial aspalathin dose from both the test solution and extract permeated through the skin, which was in accordance with the prediction from its log P value of -0.347. A portion of 0.07% of the initial aspalathin dose penetrated the different layers of the skin for the green Rooibos extract solution and 0.08% for the pure aspalathin solution. The transport of aspalathin across Caco-2 cell monolayers was concentration dependent and reached almost 100% (P(app) = 20.93 x 10(-6) cm/s) of the initial dose in the highest concentration tested for the extract, while it was only 79.03% (P(app) = 15.34 x 10(-6) cm/s) of the initial dose for the highest concentration of the aspalathin solution.
(n° 315) The antimutagenic activity of the major flavonoids of rooibos (Aspalathus linearis): some dose-response effects on mutagen activation-flavonoid interactions.
Snijman PW, Swanevelder S, Joubert E, Green IR, Gelderblom WC., Mutat Res. 2007 Jul 28;631(2):111-23. Epub 2007 Apr 21., University of Stellenbosch, Matieland, South Africa.
The antimutagenic properties of the most prevalent flavonoids in rooibos (Aspalathus linearis) were compared in the Salmonella typhimurium mutagenicity assay using tester strains TA98 and TA100 with, respectively, 2-acetamido-fluorene (2-AAF) and aflatoxin B(1) (AFB(1)) as mutagens in the presence of metabolic activation. The flavonoids included the dihydrochalcones aspalathin and nothofagin and their flavone analogues, orientin and isoorientin, and vitexin and isovitexin, respectively, as well as luteolin, chrysoeriol, (+)-catechin, quercetin, isoquercitrin, hyperoside and rutin. Flavonoid-mutagen interactions ranged from antimutagenic, comutagenic and promutagenic to mutagenic, while dose-response effects were mutagen-specific and ranged from typical to atypical including biphasic and threshold effects. Aspalathin and nothofagin and their structural flavonoid analogues displayed moderate antimutagenic properties while luteolin and to some extent, chrysoeriol, showed activities comparable to those of the green tea flavonoid (-) epigallocatechin gallate (EGCG). Apart from their mutagenic and promutagenic properties, quercetin and isoquercitrin exhibited concentration-dependent comutagenic and/or antimutagenic effects against 2-AAF- and AFB(1)-induced mutagenesis.
(n° 316) Selective bronchodilatory effect of Rooibos tea (Aspalathus linearis) and its flavonoid, chrysoeriol.
Khan AU, Gilani AH.DEur J Nutr. 2006 Dec;45(8):463-9. Epub 2006 Nov 1. Dept. of Biological and Biomedical Sciences, The Aga Khan University Medical College, Karachi, 74800, Pakistan.
Rooibos tea (Aspalathus linearis) is commonly used for hyperactive gastrointestinal, respiratory and cardiovascular disorders.The aqueous extract of Rooibos tea (RT) was studied for the possible bronchodilator, antispasmodic and blood pressure lowering activities in an attempt to rationalize some of its medicinal uses. Among the tested pure compounds of Rooibos, chrysoeriol showed selective bronchodilator effect. Chrysoeriol (luteolin 3'-methyl ether) is a bioactive flavonoid known for antioxidant, antiinflammatory, antitumor, antimicrobial, antiviral, and free radical scavenging activities.These results indicate that the bronchodilator, antispasmodic and blood pressure lowering effects of Rooibos tea are mediated predominantly through K(ATP) channel activation with the selective bronchodilatory effect. This study provides a sound mechanistic basis for the wide medicinal use of Rooibos tea, with the therapeutic potential to be developed for congestive respiratory ailments.
(n° 317) Phytoestrogens from Aspalathus linearis.
Shimamura N, Miyase T, Umehara K, Warashina T, Fujii S., Biol Pharm Bull. 2006 Jun;29(6):1271-4., University of Shizuoka, Shizuoka, Japan.
From the leaves of Aspalathus linearis, 24 known compounds and a new one, aspalalinin (25), were isolated. The structures of the compounds were determined mainly based on spectral evidence. The absolute configuration of aspalalinin was presented on the basis of X-ray analysis. Each isolate showed the estrogenic activity.
(n° 318) Antioxidant and pro-oxidant activities of aqueous extracts and crude polyphenolic fractions of rooibos (Aspalathus linearis).
Joubert E, Winterton P, Britz TJ, Gelderblom WC., J Agric Food Chem. 2005 Dec 28;53(26):10260-7., ARC , Stellenbosch 7599, South Africa.
Unfermented rooibos tea is known to contain higher levels of total polyphenols and flavonoids than its fermented counterpart, making it the obvious choice for the preparation of flavonoid-enriched fractions. Fermentation (i.e., oxidation) of rooibos decreased the pro-oxidant activity of aqueous extracts, which was contributed to a decrease in their dihydrochalcone content. The in vitro pro-oxidant activity displayed by flavonoid-enriched fractions of rooibos demonstrates that one must be aware of the potential adverse biological properties of potent antioxidant extracts utilized as dietary supplements.
(n° 319) Rooibos tea (Aspalathus linearis) partially prevents oxidative stress in streptozotocin-induced diabetic rats.
Ulicná O, Vancová O, Bozek P, Cársky J, Sebeková K, Boor P, Nakano M, Greksák M., Physiol Res. 2006;55(2):157-64. Epub 2005 May 24., Comenius University, Bratislava, Slovak Republic.
The aim of this study was to investigate the effects of rooibos tea as a natural source of a wide scale of antioxidants on the prevention and treatment of oxidative stress in streptozotocin-induced diabetic rats. Expected significant changes of biochemical parameters characteristic for experimental diabetic state were found in plasma and tissues eight weeks after single dose streptozotocin application. Administration of aqueous and alkaline extracts of rooibos tea (or N-acetyl-L-cysteine for comparison) to diabetic rats did not affect markers of the diabetic status (glucose, glycated hemoglobin and fructosamine). Besides the parameters characterizing hepatotoxic effect of streptozotocin, rooibos tea significantly lowered advanced glycation end-products (AGEs) and malondialdehyde (MDA) in the plasma and in different tissues of diabetic rats, particularly MDA concentration in the lens. From these results we can conclude that antioxidant compounds in rooibos tea partially prevent oxidative stress and they are effective in both hydrophobic and hydrophilic biological systems. Therefore, rooibos tea as a commonly used beverage can be recommended as an excellent adjuvant support for the prevention and therapy of diabetic vascular complications, particularly for protecting ocular membrane systems against their peroxidation by reactive oxygen species.
(n° 320) Antioxidant activity and protective effect on DNA strand scission of Rooibos tea (Aspalathus linearis).
Lee EJ, Jang HD., Biofactors. 2004;21(1-4):285-92., Hannam University, Daejeon, Korea.
Rooibos tea (Aspalathus linearis) was extracted by refluxing with water and 75% ethanol as a solvent. Antioxidant activity and protective effect on DNA strand scission were investigated by using different antioxidant assay systems and DNA strand nicking assay, respectively. This result indicates that total soluble phenolics, specially flavonoid, of Rooibos tea are responsible for several kinds of antioxidant activities and preventive activity on peroxyl radical induced DNA strand scission.
(n° 321) Anti-human immunodeficiency virus activity of oligosaccharides from rooibos tea (Aspalathus linearis) extracts in vitro.
Nakano M, Nakashima H, Itoh Y., Leukemia. 1997 Apr;11 Suppl 3:128-30., Aichi Medical University, Japan.
The active substances, acid polysaccharides, were extracted with 1% sodium hydroxide from the leaves of rooibos tea (Aspalathus linearis), Du Zhong Cha (Eucommia ulmoides Oliv.) and Japanese tea leaves (Camellia sinensis var. sinensis). The alkaline extracts of Rooibos tea and Du-Zhong tea leaves, but not Japanese tea leaves suppressed the HIV-induced cytopathicity using HIV (HTLV-III) infected MT-4 cells, having extremely low cytotoxicity: Its 50% effective concentration (EC50) was 12-67 micrograms/mL, white 50% cytotoxic concentration (CC50) was higher than 1.0 mg/mL. The active substances were purified with ethanol precipitation. The substances were composed of 27% of reducing sugar, 46% of neutral sugars and 22% of uronic acid. A LD50 of the alkaline extracts from rooibos tea was higher than 1.2 g/kg body weight. Acid degradated substances composed of disaccharides and trisaccharides, were also suppressed the HIV-induced cytopathicity. From these results, it is probable that acid polysaccharides from rooibos tea were extremely safe, and that HIV infection may be suppressed by daily intake of the alkaline extracts of rooibos tea and Du-Zhong tea.
(n° 322) Polysaccharide from Aspalathus linearis with strong anti-HIV activity.
Nakano M, Itoh Y, Mizuno T, Nakashima H., Biosci Biotechnol Biochem. 1997 Feb;61(2):267-71., Aichi Medical University, Japan.
Polysaccharide that has been extracted with 1% sodium carbonate from Rooibos leaves (Aspalathus linearis) showed strong anti-HIV activity. Du-Zhong leaves also showed anti-HIV activity, although lower than the extract of Aspalathus linearis, but Japanese tea leaves and a hot water extract of Aspalathus linearis did not. The anti-HIV activity of the alkaline extract from Aspalathus linearis was recovered mainly in the 25-75% ethanol-precipitated fraction. The polysaccharide almost completely inhibited the binding of HIV-1 to MT-4 cells. It is inferred from these results that the polysaccharide from Aspalathus linearis is involved in the mechanism for virus binding to T cells.
(n° 323) Effect of Rooibos tea (Aspalathus linearis) on chick skeletal muscle cell growth in culture.
Lamosová D, Juráni M, Greksák M, Nakano M, Vaneková M., Comp Biochem Physiol C Pharmacol Toxicol Endocrinol. 1997 Jan;116(1):39-45., Slovak Academy of Sciences, Ivanka pri Dunaji, Slovakia.
Rooibos tea (RT) extract contains natural antioxidants and scavenging agents. We investigated the effects of different concentrations of RT extract in medium on growth and changes of growth parameters of cultured chick embryonic skeletal muscle cells. . The inhibition effect of RT rose with increasing concentration of the tea extract in the culture medium. Ornithine decarboxylase activity was significantly affected only by 100% RT extract in every examined cell types. These results suggest that the inhibitory effect of RT extract on the growth of primary cells, fibroblasts and myoblasts is due to the potent scavenging activity of the RT extract.
(n° 324) Radioprotective effects of antioxidative plant flavonoids in mice.
Shimoi K, Masuda S, Shen B, Furugori M, Kinae N., Mutat Res. 1996 Feb 19;350(1):153-61., University of Shizuoka, Japan.
Radioprotective effects of tea infusions and plant flavonoids were investigated by using the micronucleus test for anticlastogenic activity and the thiobarbituric acid assay for antioxidative activity. A single gastric intubation of rooibos tea (Aspalathus linearis) infusion at 1 ml per mouse 2 h prior to gama-ray irradiation (1.5 Gy) reduced the frequency of micronucleated reticulocytes (MNRETs). After the fractionation of rooibos tea infusion, the flavonoid fraction was found to be most anticlastogenic and antioxidative. . These results suggest that plant flavonoids, which show antioxidative potency in vitro, work as antioxidants in vivo and their radioprotective effects may be attributed to their scavenging potency towards free radicals such as hydroxyl radicals. Therefore, the flavonoids contained in tea, vegetables and fruits seem to be important as antioxidants in the human diet.
(n° 325) The suppression of age-related accumulation of lipid peroxides in rat brain by administration of Rooibos tea (Aspalathus linearis).
Inanami O, Asanuma T, Inukai N, Jin T, Shimokawa S, Kasai N, Nakano M, Sato F, Kuwabara M., Neurosci Lett. 1995 Aug 18;196(1-2):85-8., Iwate University, Morioka, Japan.
The protective effects of Rooibos tea (RT), Aspalathus linearis, against damage to the central nervous system (CNS) accompanying aging were examined by both the thiobarbituric acid reaction (TBA) and magnetic resonance imaging (MRI) methods in brains of chronically RT-treated rats. The contents of TBA reactive substances (TBARS) in the frontal cortex, occipital cortex, hippocampus and cerebellum in 24-month-old rats after administration with water were significantly higher than those in young rats (5 weeks old). However, no significant increase of TBARS was observed in RT-administered aged rats. These observations suggested that (1) the age-related accumulation of lipid peroxides in the brain was closely related to the morphological changes observed by MRI, and (2) chronic RT-administration prevented age-related accumulation of lipid peroxides in several regions of rat brain.
(n° 326) Inhibitory effects of Rooibos tea, Aspalathus linealis, on X-ray-induced C3H10T1/2 cell transformation.
Komatsu K, Kator K, Mitsuda Y, Mine M, Okumura Y., Cancer Lett. 1994 Feb 28;77(1):33-8., Nagasaki University School of Medicine, Japan.
Oncogenic transformation of mouse C3H10T1/2 cells induced by X-rays was suppressed in the presence of extract of Rooibos tea, Aspalathus linealis. Transformation was reduced with increased concentration of the extract, so that at an extract concentration of 10%, transformation incidence was similar to the spontaneous level. Suppression was also dependent on treatment time with the extract and was maximal when present during the entire incubation period. In contrast, green tea extract at an equitoxic concentration showed no detectable effect on transformation incidence
(n° 327) The clastogen-suppressing effects of green tea, Po-lei tea and Rooibos tea in CHO cells and mice.
Sasaki YF, Yamada H, Shimoi K, Kator K, Kinae N., Mutat Res. 1993 Apr;286(2):221-32, University of Shizuoka, Japan.
The suppressing effects of crude extracts of three kinds of tea-green tea (GT) from Japan, Po-lei tea (PT) from China, and Rooibos tea (RT) from South Africa-on the induction of chromosome aberrations in cultured CHO cells and mice were studied. When CHO cells were exposed to each tea extract in the presence of rat liver microsomal enzymes (S9 mix) together with benzo[a]pyrene (B(a)P) or mitomycin C (MMC), a decrease in the frequency of chromosome aberrations was observed. PT and RT, but not GT. These data suggest that catechines, well-known antimutagens in tea samples, might account for the inhibitory effect in the case of GT and PT. Since RT contains few catechines, several unknown antimutagenic components could be responsible for its effect. The antimutagenic effects of tea extracts at concentration levels consumed by humans were examined in mice using micronucleus induction with B(a)P or MMC. In conclusion, intake of tea might suppress the mutagenic activity of certain potent mutagens in human beings.
(n° 328) [The effect of rooibos tea on iron absorption].
Hesseling PB, Klopper JF, van Heerden PD., S Afr Med J. 1979 Apr 14;55(16):631-2.,
A study was carried out to determine if rooibos tea (Aspalathus linearis) has a deleterious effect on iron absorption similar to that of ordinary tea (Camellia sinensis). Three groups of volunteers, each consisting of 10 healthy young men comparable with regard to iron status and body dimensions, were studied. After ingestion of 1 muCi 59Fe and 16 mg of elemental iron, group A drank rooibos tea, group B ordinary tea and group C boiled water. Iron absorption was measured 14 days later with a whole body counter. Mean iron absorption after ingestion of rooibos tea, ordinary tea, and water was 7,25%, 1,70% and 9,34% respectively. In contrast to ordinary tea (P less than 0,0001), rooibos tea did not affect iron absorption significantly. The ascorbic acid content of rooibos tea varies between 121,8 and 154,9 mumol/l, depending on the method of preparation. Rooibos tea contains small amounts of iron, magnesium, phosphorus, sodium, chloride and potassium. These findings have practical nutritional and therapeutic implications.
(n° 329) An evaluation of the inhibitory effects against rotavirus infection of edible plant extracts.
Knipping K, Garssen J, Van't Land B., Virol J. 2012 Jul 26;9(1):137.
Rotaviruses are the single most important cause of severe diarrhea in young children worldwide. The developments of specific, potent and accessible antiviral treatments that restrain rotavirus infection remain important to control rotavirus disease. These results indicate that nutritional intervention with extracts of Nelumbo nucifera Gaertn., Aspalathus linearis (rooibos) Burm.f.) R.Dahlgren, Urtica dioica L., Glycyrrhiza glabra L. and Olea europaea L. (olijfolie) might be useful in the treatment of diarrhea caused by rotavirus infection.
(n° 330) 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., Peninsula University of Technology, Bellville, 7535, 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. 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.
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