CANSA excited by latest research showing that Rooibos can boost “master” antioxidant – glutathione. Dr Carl Albrecht, Head: Research, CANSA, August 2009 reports that over the last decade, CANSA has invested more than R1 million to support research on Rooibos extract as a possible, natural cancer-preventive product. Most of the work has been done at the PROMEC Unit of the Medical Research Council (MRC) in Cape Town under the leadership of Prof Wentzel Gelderblom. The South African Rooibos Council also contributed research funding.1
During this time, Professor Gelderblom and his research partners published their research results in several peer-reviewed journals. These articles provide details on their findings that Rooibos extracts are able to prevent many aspects of carcinogenesis (the process of cancer formation).2,3,4,5
A very significant discovery was that rats who drank Rooibos tea, as their only source of liquid, for ten weeks, had a five-fold elevation of the ratio of reduced glutathione to oxidised glutathione. Black tea and green tea were found to be inferior and did not even double the ratio.6
Glutathione is the master anti-oxidant in the body.7 It is made by the body, especially the liver, and cannot be taken as a supplement because it is broken down in the gut.8 It decreases with ageing9 and smoking10. Glutathione has been found in many studies to counteract heart diseases, cancers and ageing. 7,11,12,13,14.15
Consequently, it is reasoned that if Rooibos can elevate the reduced glutathione to oxidised glutathione ratio (GSH/GSSG), this remarkable effect could help to reduce the risk of cancer (and other lifestyle diseases).
In another recent study (not yet published) South African by Professor Jeanine Marnewick of the Cape Peninsula University of Technology, also found that Rooibos tea taken as six cups a day for three months, by healthy volunteers, elevated blood glutathione by 100%.16 Similar results were found by Nikolova and colleagues17.
CANSA is excited about these results and believes that they point to growing convergence of evidence that Rooibos could play an important role in reducing the risk of cancer in South Africa.
What is also pleasing, is that this tea is quite natural, safe to use and relatively inexpensive. It is also the most successful indigenous plant product to be commercialised and is exported all over the world.
CANSA and the South African Rooibos Council are currently planning joint research into clinical Rooibos effects in human cohort groups in the future. Questions that need answering include; How many cups of tea per day are needed for optimal reduced-glutathione-ratio enhancement? Can Rooibos tea enhance the reduced-glutathione-ratio in smokers and the elderly? Is there a correlation between drinking Rooibos every day and various aspects of health?
References
1.South African herbal teas: Aspalathus linearis, Cyclopia spp. And Atrixia phylicoides – A Review, E. Joubert, W.C.A. Gelderblom, A. Louw, D. de Beer, Journal of Ethnopharmacology, 119 (2008), 376-412
2.An investigation on the antimutagenic properties of South African herbal teas, Marnewick, J.L., gelderblom, W.C.A., Joubert, E., Mutation Research, 471, (2000), 157-166
3.Ex vivo modulation of chemical-induced mutagenesis by subcellular liver fractions of rats treated with Rooibos (Aspalathus linearis) and honeybush (Cyclopia intermedia) as well as a green and black (Camellia sinensis) teas, Marnewich, J.L., Batenburg, W., Swart, P., Joubert, E., Swanefelder, S., gelderblom, W.C.A., Mutation Research, 558, (2004), 145-154
4.Inhibition of tumour promotion in mouse skin by extracts of Rooibos (Aspalathus linearis) and honeybush (Cyclopia intermedia), unique South African herbal teas, Marnewick, J.L., Joubert, E., Joseph, S., Swanefelder, S.,Swart, P., Gelderblom, W.C.A., Cancer Letters, 224 (2005), 193-202
5.A comparative study on the antimutagenic properties of aqueous extracts of Aspalathus linearis (Rooibos), different Cyclopia spp. (honeybush) and camellia sinensis teas, Van der merwe, J.D., Joubert, E., Richards, E.S., Manley, M., Snijman, P.W., Marnewick, J.L., Gelderblom, W.C.A., Mutation Research, 611, (2006), 42-53
6.Modulation of hepatic drug metabolising enzymes and oxidative status of Rooibos (Aspalathus linearis) and honeybush (Cyclopia intermedia), green and black (Camellia sinensis) teas in rats, Marnewich, J.L., Joubert, E., Swart, P., Van der Westhuizen, F., gelderblom, W., Journal of Agricultural and Food Chemistry, 51, (2003), 8113-8119
7.The central role of glutathione in the pathophysiology of human diseases, Franco, R., Schoneveld, O. J., Pappa, A., Panaviotidis, M.I., Arch Physiol Biochem., 113, (2007), 234-258
8.The systemic availability of oral glutathione, Witschi, A., Reddy, S., Stofer, B., Lauterburg, B.H., Eur J Clin Pharmacol., 43, (1992), 667-669
9.Mitochondrial glutathione, a key survival antioxidant, Mari, M., Morales, A., Colell, A., Garcia-Ruiz, C., Fernandez-Checa, J.C., Antioxid Redox Signal., Jun 26, 2009
10.Effect of age on alteration of glutathione metabolism following chronic cigarette smoke inhalation in mice, Teramoto, S., Uejima, Y., Teramoto, K., Ouchi, Y., Fukuchi, Y., Lung, 174, (1996), 119-126
11.The importance of glutathione in human disease, Townsend, D.M., Tew, K.D., Tapiero, H., Biomed Pharmacother., 57, (2003), 145-155
12.Therapeutic potential of glutathione, Exner, R., Wessner, B., Manhart, N., Roth, E., Wien Klin Wochenschr., 112, (2000), 610-616
13.Glutathione metabolism and its implications for health, Wu, G., fang, Y.Z., Yang, S., Lupton, J.R., Turner, N.D., J Nutr., 134, (2004), 489-492
14.Reduced glutathione system: role in cancer development, prevention and treatment (Review), Locigno R, Castronovo, V., Int J Oncol., 19, (2001), 221-236
15.Glutathione dysregulation and the etiology and progression of human diseases, Ballatori, N., Krance, S.M., Notenboom, S., Shi, S., Tieu, K., Hammond, C.L., Biol. Chem., 390, (2009), 191-214
16.Rooibos and heart disease, Unpublished studies. Marnewick, J., Rooibos Science Café, MTN ScienCentre, Cape Town, 26 November, 2008
17.Antioxidant effects of rooibos tea on workers occupationally exposed to lead, Nikolova, V., Petrova, S., Petkova, V., Pavlova, A., Georgieva, T., Toxicology letters, 172 (S), (2007), 120-121
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