Tea polyhenols is a kind of natural compound substance extracted from tea, which is made up of flavones, flavonols and glyconsides etc. Among them, Catechin (belonging to flavonols) is the most important, for it takes up 60-80% in total polypehnols. Catechins is made up of GEC、D，L-C、EC、EGCG、GCG、ECG and so on. Catechins ,with rich epigallocatechin gallate, is easy to have some changes such as oxidation, polymerization, contraction, so it has the ability to prevent oxidation and remove free radicals.
