Rooibos Tea: A Delicious Cup of Health

This tasty red tea from South Africa is rich in health benefits
By Cornelia Carison, Ph.D.

A new tea is vying for time in your tea cup-and your health regiment. Rooibos (pronounced ROY-bos) is a recent addition to the tea trade, and this dramatically red-colored herb is making its way onto shelves of health-food stores nationwide. It can also make a healthful contribution to your diet. The therapeutic value of Rooibos tea has been recognized for centuries in South Africa, where both indigenous peoples and colonial settlers drank it to treat nervousness, indigestion, allergies, and minor skin problems. Current studies validate some of these uses. Of greatest interest is the herb's high anti-oxidant content and related potential to) prevent mutation that may lead to cancer. Rooibos is caffeine free and low in tannins-a boon to tea lovers who can't tolerate either compound.

Cancer prevention. Although preliminary studies suggest that drinking Rooibos) tea may help prevent malignant mutations, the number of investigations remains small, and most of them have been conducted in Japan.
Here's a summary of the research. Research conducted in 1993 in Japan shows, that Rooibos suppressed malignant cell changes in mice when added to drinking water; it also suppresses malignant cell changes in cell cultures when added to the culture medium. In several experiments, Rooibos and green tea did comparably well. In one study, green tea did nothing while Rooibos showed strong inhibitory activity. Because Rooibos contains only a small amount of catechins (the compounds primarily responsible for the green tea anti-oxidant capacity~) it seems likely that Rooibos gets its antimutagenic potential from different set of molecules. Research published in Mutation Research found that Rooibos tea inhibited premalignant changes in the tissue-cultured mouse cells that were exposed to X-rays. The inhibiting action took place when cells were treated with as little a 2 percent Rooibos solution (roughly equivalent to 2/3 cup a day for humans) an peaked when cells were treated with 10 percent solution (a little more than 3 cups) At the higher concentration, the rate of the transformation was no greater than that of normal, non-irradiated cells. Rooibos also protect mice against gamma radiation. Mice treated with 1 mI of Rooibos tea two hrs. before irradiation experienced less DNA damage than untreated mice. (For a human, this equal about 4 liters "7 pints of double-strength tea.) One molecule, luteolin, appears to be responsible for the greatest inhibition.

Anti-oxidant content. Rooibos is richly endowed with wide spectrum of antioxidant phenolic acid and flavonoids. Although several of these (such as quercitin, rutin, luteolin and caffeic acid) occur in other vegetables and fruit, one is unique to Rooibos. Called aspalathin, its anti-oxidant activity is comparable to that of vitamin E and occurs in high concentration. Aspalathin constitutes roughly 1.5 percent of dry Rooibos leaves.

Brain benefits. Scientists working in another Japanese laboratory discovered that Rooibos suppresses age-related brain deterioration. Rats who drank nothing but Rooibos tea from ages 3 to 24 months showed little change in several classes of brain function when compared to three-months-old rats. The relevance to human brain function remains to be determined.

Anti-HIV activity. Two further studies in Japan indicate that Rooibos contain~ at least one substance that inhibits binding of HIV-1 to MT-4 lymphocytes, the cells that the virus targets. To date, the active molecule is not fully described. Scientists do know that it's a polysaccharide containing uronic acid and various sugars, and that it is soluble in sodium hydroxide or sodium carbonate but not in hot water. This means that normal brewing conditions will not release the active compound into tea.

References:
Inanami, O., et al "The suppression of age-related accumulation of lipid peroxides in rat brain by administration of Rooibos tea (Aspalathus linearis) Neuroscience Letters 1955, 196:85-8 Komatsu, K., et al.
Inhibitory effects of Rooibos tea, Aspalathus linearis, on X-ray-induced C3HIOTII2 cell transformation. "Cancer Letters 1994, 77:33-38 Nakano, M., et al.
"Anti-human immunodeficiency virus activity of oligosaccharides from Rooibos tea (Aspalathus linearis) extract in vitro "Leukemia 1997, l1, supplement 3:128-130 Polysaccharide from Aspalathus linearis with strong anti-HIV activity. Bioscience, Biotechnology and Biochemistry 1997, 61:267-271 Sasaki, Y. et al.
"The clastogen-suppessing effects of green tea, Po-lei tea, and Rooibos tea in CHO cells and mice. Mutation Research 1993,286:221-232 Shimoi, K. et al." Radioprotective effects of anti-oxidative plant flavonoids in mice". Mutation Research 1996,350:153-161. Von Gadow, A. et al.
"Comparison of the antioxidant activity of aspalathin with that of other plant phenols of Rooibos tea (Aspalathus linearis), alpha tocophenor, BHT, and BHA"Journal of Agricultural and Food Chemistry 1997, 45:632-638 "Effect of extraction time and additional heating on the anti-oxidant activity of Rooibos) s tea (Aspalathus linearis) extracts Journal of Agricultural and food Chemistry 1997,45:1370-1374

Cornelia Carlson holds doctorate in biochemistry and
is an avid grower and user of herbs.
Reprint from "Herbs for Health" magazine, November/December 2000