RESUMO
Oxidative damage to membrane lipid is one of the prime events occurring in aging and other undesirable physiological processes. In this study experiments were performed on liposomes [prepared either from crude erythrocyte phospholipids or purified egg yolk phosphatidylcholine] as models of lipid bilayer portion of biomembranes. The effects of beta-carotene, and phospholipid composition on peroxidation process, initiated by Fe[2+], were studied. It was found that beta-carotene does not show any noticeable antioxidant effect on the peroxidation process initiated by Fe[2+] in liposomes prepared from erythrocyte phosphatides, whereas it effectively suppressed the same process in egg yolk phosphatidylcholine [EYPC]. It is concluded that the anti-/pro-oxidant activity of beta-carotene is also dependent on the membrane lipid composition and this may provide an explanation about the conflicting reports on its role in ordinary or promoted oxidation experiments