Green tea belittles cancer.Nutritionists have been touting green tea's anticancer benefits for years. Studies have shown that people who drink it tend to develop fewer cancers and that animals administered the brew derive similar benefits (SN: 8/31/91, p. 133). How this tea works its magic, however, has remained an open question. Researchers at Purdue University Purdue University (pərdy  `, -d`), main campus at West Lafayette, Ind. in West Lalayette, Ind., now think they've stumbled upon at least part of the answer. Green tea contains a potent antioxidant antioxidant, substance that prevents or slows the breakdown of another substance by oxygen. Synthetic and natural antioxidants are used to slow the deterioration of gasoline and rubber, and such antioxidants as vitamin C (ascorbic acid), butylated hydroxytoluene with the unwieldy name of epigallocatechin gallate Epigallocatechin gallate (EGCG) is a type of catechin and is the most abundant catechin in tea. According to one researcher[1] epigallocatechin-3-gallate is an antioxidant that helps protect the skin from UV radiation-induced damage and tumor formation. , or EGCg. Biochemist D. James Morre and his colleagues find that this compound shuts down quinol-oxidase, an enzyme that cancer cells cells once believed to be peculiar to cancers, but now know to be epithelial cells differing in no respect from those found elsewhere in the body, and distinguished only by peculiarity of location and grouping. See also: Cancer need to divide and reproduce. While normal cells also rely on this enzyme to grow and proliferate, EGCg's enzyme-inhibiting effect appears to be restricted to tumor cells. The tea constituent seems to thwart a cancer by halting the enlargement of its cells--something that "is clearly not an antioxidant function," Morre notes. Many cancer-fighting nutrients studied so far have proved capable of disabling oxidants. In the test tube, when EGCg-stunted cells fail to reach a critical size needed to divide, they succumb to a programmed cell death pro·grammed cell death n. See apoptosis. programmed cell death proposed system of cell death, often including poly(ADP)-ribosylation, ensures that a cell will not survive if it is so badly damaged that its recovery would harm the . Ordinarily, tumor cells live indefinitely. But what about black tea, the brew consumed by about 80 percent of tea drinkers around the world? It also contains EGCg, though in far smaller concentrations than green tea. Both teas are prepared from leaves of the same plant. Morre suspects that black tea's paucity of EGCg explains why it's only one-tenth to one-hundredth as potent as green tea at inhibiting the quinoloxidase reaction in test-tube-grown cancer cells. However, "there's no reason why you shouldn't derive some benefit from drinking black tea"--especially if it's sipped regularly through the day to ensure that at least a little EGCg is usually present in the body, concludes Morre, himself a heavy consumer of this more popular brew. He and Dorothy M. Morre reported their team's findings in San Francisco San Francisco (săn frănsĭs`kō), city (1990 pop. 723,959), coextensive with San Francisco co., W Calif., on the tip of a peninsula between the Pacific Ocean and San Francisco Bay, which are connected by the strait known as the Golden last month at the American Society for Cell Biology Cell biology The study of the activities, functions, properties, and structures of cells. Cells were discovered in the middle of the seventeenth century after the microscope was invented. annual meeting. |
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