Effect of the combined action of flavonoids, ascorbate and alpha-tocopherol on peroxidation of phospholipid liposomes induced by Fe2+ ions

The effect of alpha-tocopherol, ascorbate, rutin and dihydroquercetin on chemiluminescence (CL) accompanying the Fe2+-induced peroxidation of unsaturated fatty acids in phospholipid liposomes has been investigated. The amplitude of CL decreased and the latent period increased in the presence of alpha-tocopherol, rutin and dihydroquercetin which is typical of peroxide radical traps. Ascorbate also reduced the CL amplitude but only at small concentrations up to about 4 microM. A further increase of ascorbate concentration had a negligible effect on the amplitude. At the same time, the latent period in CL development increased with the growth of ascorbate concentration, apparently, as a result of recycling of divalent iron oxidized in the course of lipid peroxidation. The effects of rutin and dihydroquercetin on the liposomal CL in the presence of alpha-tocopherol and ascorbate in all experiments were almost the same as when these compounds were added individually. The antioxidant effects were merely summed up without any mutual enhancement or inhibition of each other's action.