DIETARY FLAVONOIDS AND INTERACTION WITH ENDOGENOUS ANTIOXIDANTS

Green tea catechins were given to healthy volunteers under controlled diet for 4 consecutive weeks. Plasma concentrations of ascorbate, urat e, alpha-tocopherol, beta-carotene and blood levels of total glutathio ne were measured before, after the supplementation and the washout per iod. RBC membranes were assayed for their levels of alpha-tocopherol a nd phosphatidylcholine PUFA's. Catechin intake provides antioxidant pr otection in vivo through a cascade involving endogenous antioxidants, which interact differently according to their redox potentials and pol arity. As a final beneficial effect, liposoluble vitamin E and beta-ca rotene are spared by catechins, resulting in an overall protection aga inst oxidative modification of RBC membrane PUFA's.