THE INFLUENCE OF LIPID COMPOSITION AND β-CAROTENE ON LIPID PEROXIDATION IN LIPOSOMES

Oxidative damage to membrane lipid is one of the prime events occurring in aging and other undesirablephysiological processes. In this study experiments were performed on liposomes (prepared either from crudeerythrocyte phospholipids or purified egg yolk phosphatidylcholine) as models of lipid bilayer portion ofbiomembranes. The effects of β-carotene, and phospholipid composition on peroxidation process, initiatedby Fe2+, were studied. It was found that β-carotene does not show any noticeable antioxidant effect on theperoxidation process initiated by Fe2+ in liposomes prepared from erythrocyte phosphatides, whereas iteffectively suppressed the same process in egg yolk phosphatidylcholine (EYPC). It is concluded that theanti-/pro-oxidant activity of β–carotene is also dependent on the membrane lipid composition and thismay provide an explanation about the conflicting reports on its role in ordinary or promoted oxidationexperiments.