Catechins.
Tea catechins are responsible for the astringent taste of green tea. Catechins of green tea leaves are account for about 10 % of dry w eight, including （-）- epigallocatechin gallate（ EGCg）50 %,（-）- epigallocatechin（ EGC）30 %,（-）- epicatechin gallate （ECg）10 % and（-）- epicatechin（EC）10 %. Crystals of catechins are sampled in the photographs on the right. A variety of biological activities are attributed to anti-oxidative, radioprotective, ant-mutagenic, antitumor, anti-hyperglycemic, anti-hypercholesterolemic, fat reducing, anti-ulcer, anti-bacterial, bowel modulating, anti-viral, anti-carious, anti-hypertensive actions and the inhibitory activity of some enzymes. ■ Cancer Chemoprevention : Recently, some review articles have reported the relationship between the tea consumption and the human cancer risk. A general overview of the pertinent epidemiological studies on tea consumption and cancer prevention in different organs such as bladder and urinary tract, breast, colon a...