Catechin is a polyphenolic flavonoid which has been isolated from a variety of natural sources including tea leaves, grape seeds, and the wood and bark of trees such as acacia and mahogany. Catechin is a more potent antioxidant than ascorbate or α-tocopherol in certain in vitro assays of lipid peroxidation. Catechin inhibits the free radical-induced oxidation of isolated LDL by AAPH. It has also been reported to act as an inhibitor of COX-1 with an IC50 of about 80 µM. Catechin and other related procyanidin compounds have antitumor activity when tested in a two-stage mouse epidermal carcinoma model employing topical application.
1.Zhao, J.,Wang, J.,Chen, Y., et al. Anti-tumor-promoting activity of a polyphenolic fraction isolated from grape seeds in the mouse skin two-stage initiation-promotion protocol and identification of procyanidin B5-3/'-gallate as the most effective antioxi