Lignan Polyphenols May Contribute to the Protective Effect of Tea on Coronary Heart Disease.
Mazur W M, Wahala K, Rasku S, Salakka A, Hase T, Adlercreutz H. Br. J Nutr 1998 Jan, VOL: 79 (1), P: 37-45, ISSN: 0007-1145

Tea is a beverage consumed widely throughout the world. The existence in tea of chemopreventing compounds possessing antimutagenic, anticarcinogenic and antioxidative properties has been reported. High intakes of tea and foods containing flavonoids have recently been shown to be negatively correlated to the occurrence of CHD. However, tea may contain other compounds with similar activities. Using a new gas chromatographic-mass spectrometric method we measured lignans and isoflavonoids in samples of twenty commercial teas (black, green and red varieties) and, for comparison, six coffees. Both unbrewed and brewed tea were investigated. The analysis of the teas yielded relatively high levels of the lignans secoisolariciresinol (5.6-28.9 mg/kg; 15.9-81.9 mumol/kg) and matairesinol (0.56-4.13 mg/kg; 1.6-11.5 mumol/kg) but only low levels of isoflavonoids. Because the plant lignans, as well as their mammalian metabolites enterolactone and enterodiol, have antioxidative properties and these mammalian lignans occur in high concentrations in plasma, we hypothesise that lignan polyphenols may contribute to the protective effect of tea on CHD.

Acute And Chronic Tea Consumption Reverses Endothelial Dysfunction In Patients With Coronary Artery Disease
Stephen J Duffy, Boston University School of Medicine, Boston, MA; Balz Frei, Linus Pauling Institute, Corvalis, OR; Monika Holbrook, Peter Swerdloff, Elizabeth S Biegelsen, Noyan Gokce, Ross M Germani, Judson D Russell, John F Keaney Jr, Joseph A Vita, Boston University School of Medicine, Boston, MA

Epidemiological studies suggest that tea consumption is associated with decreased cardiovascular disease risk, but the mechanisms of benefit remain undefined.
Endothelial dysfunction has been associated with coronary artery disease and increased oxidative stress. Antioxidants have been shown to reverse endothelial dysfunction and tea contains antioxidant flavonoids.

To test the hypothesis that tea consumption will reverse endothelial dysfunction, we randomized 50 patients aged 55 ± 8 (mean ± SD) years with proven coronary artery disease to either 450 ml of black tea or water consumed acutely, followed by 900 ml of tea or water daily for 1 month in a cross-over design. Vascular function and blood parameters were assessed at baseline, 2 hours and 1 month after beverage consumption.

Acute and chronic tea consumption improved flow-mediated dilation (FMD), while consumption of water had no effect (P < 0.001 ANOVA). Tea consumption had no effect on the response to the endothelium-independent vasodilator nitroglycerin (P = 0.55), or on resting vessel size, blood pressure, heart rate, serum lipids or glucose. An equivalent oral dose of caffeine (200 mg) had no acute effect on FMD.

In conclusion, acute and chronic tea consumption reverses endothelial vasomotor dysfunction in patients with coronary artery disease. This finding may partly explain the association between tea intake and decreased cardiovascular disease events.

STUDIES SPONSORED BY TEA RESEARCH ASSOCIATION, NATIONAL TEA RESEARCH FOUNDATION, INDIA AND FOOD & AGRICULTURE ORGANISATION OF THE UN

Epidemiological Studies on Black Tea
An Eipdemiological study on Cancer & Cardiovascular Diseases among 40+ women suffering from cardiovascular diseases, diabetes and cancer. Report of Indian Market Research Bureau. February, 2001.

To investigate whether there is a correlation between the incidence of Black Tea consumption and incidence of cancer or cardiovascular diseases, a qualitative survey has been carried out by the Indian Market Research Bureau (IMRB), using a structured questionnaire in Calcutta MC and Calcutta UA among 40+ working women belonging to different socioeconomic strata. It has been found that occurrence of diabetes and cardiovascular disease is less in population consuming 3-5 cups/day of Black Tea as compared to non-tea drinkers or minimal tea drinkers (1-2 cups/day).
Eipdemiological studies are now being conducted to examine the relationship between occurrence of cancer and consumption of Black Tea.

Black Tea enhances muscular performance
Das M, Vedasiromoni, JR, Chauhan, SPS, Ganguly DK (1994): Effect of the hot water extract of black tea (Camellia sinensis) on the rat diaphragm. Planta Medica 60, 470-471.

Black tea extract produced a concentration dependent enhancement of neuromuscular function in vitro. Failure of the extract to induce facilitation of contraction of the muscle devoid of neuronal connection indicated a strong influence of tea extract on synaptic transmission. Drug interaction studies pointed a role of calcium in the facilitatory effect of tea extract of muscle contraction.

Black Tea reduces gastric ulcer in rats
Maity S, Vedasiromoni JR, Ganguly DK (1995): Antiulcer effect of hot water extract of black tea. J. Ethnopharmacol. 46, 167-174, Maity S Vedasiromoni JR, Ganguly DK (1998): Role of glutathione in the antiulcer effect of hot water extract of black tea (Camellia sinensis). Japan J. Pharmacol.78, 285-292.

Prior oral administration of Black tea extract to rats for 7 days significantly reduced the incidence of gastric erosions and severity induced by various ulcerogens and cold stress Tea extract also favourably altered the changes in acid and peotic activity of gastric juice in these ulcertogen-treated animals. Drug interaction studies suggest a major role for gluthathione, an endogenous antioxidant, in the cytoprotection against ulceration afforded by black tea extract.