PROTECTIVE ACTION OF CAROTENOID PIGMENTS AGAINST PHOTODYNAMIC DAMAGE TO LIPOSOMES*

Abstract

Abstract— When liposomes (a model membrane system) are subjected to a dye‐sensitized photo‐oxidation, lysis, as measured by glucose leakage or a change in light scattering, results. Before lysis occurs, the membrane lipids undergo peroxidative damage, as determined by the appearance of malondialdehyde. Carotenoids incorporated into the liposomal membrane protect against both lipid peroxidation and liposomal lysis. Other 1 O 2 quenchers and free radical absorbers also protect liposomes from photodynamic damage.