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, urate, -tocopherol, -carotene and blood levels of total glutathione were measured before, after the supplementation and the wash-out period. RBC membranes were assayed for their levels of -tocopherol and phosphatidylcholine PUFA’s. Catechin intake provides antioxidant protection in vivo through a cascade involving endogenous antioxidants, which interact differently according to their redox potentials and polarity. As a final beneficial effect, liposoluble vitamin E and -carotene are spared by catechins, resulting in an overall protection against oxidative modification of RBC membrane PUFA’s.