Individual and combined antioxidant effects of seven phenolic agents in human erythrocyte membrane ghosts and phosphatidylcholine liposome systems: Importance of the partition coefficient

Antioxidant activities of seven phenolic agents against Fe2+-induced lipid oxidation were compared with alpha-tocopherol, beta-carotene, and vitamin C in human erythrocyte membrane ghosts and liposome systems. The antioxidant activity of five test flavonoids followed the order catechin > epicatechin > rutin > quercetin > myricetin in both systems (p < 0.05), which was nega tively correlated with their partition coefficients. The antioxidant intera ction of these phenolic agents with alpha-tocopherol, beta-carotene, or vit amin C in inhibiting Fe2+-induced lipid oxidation was examined. Synergistic effects were present in the combinations of alpha-tocopherol plus caffeic acid, catechin, or epicatechin as well as in all combinations of vitamin C plus phenolic antioxidants. On the basis of the stronger individual and com bined effects present in caffeic acid, catechin, and epicatechin, the appli cation of these three phenolic agents with or without alpha-tocopherol, bet a-carotene, and vitamin C may provide stronger protective benefits against lipid oxidation, which may be helpful for oxidation-related diseases preven tion.