Green Tea Contains a Possible Anti-cancer Polyphenol
~ November 1997 No.25 ~
In the June issue of the magazine Nature, a group of American scientists speculate on the possible anti-cancer effects of drinking green tea. The group from the Medical College of Ohio and the University of Toledo use sophisticated computer modeling to advance their hypothesis.
The authors point out that epidemiological studies have indicated that the consumption of green tea may be related to the reduction of cancer in humans. Animal studies have been reported in which breast and prostrate cancers have been reduced in animals receiving green tea but not black tea. Only green tea contains polyphenols called cathechins. The production of black tea destroys these relatively large and complex molecules, which may explain the different effects obtained with the two type of tea.
As cancers grow, they invade cells in the body by making use of a group of enzymes called proteolytic enzymes. The Ohio researchers showed that one prominent cathechin in green tea epigallo-cathechin-3 gallate (EGCG) was the ideal size and shape to inhibit the action of the proteolytic enzyme urokinase (uPA). Again in animal studies, the reduction in the activity of uPA lead to a reduction of tumour size or even complete remission of the cancer.
Research with computer models, together with animal trials are only first steps. But it is becoming more and more evident that tea contains many compounds that are beneficial to the health.
EPIGALLO-CATHECHIN-3 GALLATE (EGCG)
Why drinking green tea could prevent cancer