EFFECT OF LIPOPHILIC ANTIOXIDANTS ON PERO XIDATION OF LIPOSOME MEMBRANES PHOTOSENSITIZED BY HEMATOPORPHYRIN DERIVATIVES UPON HE-NE-LASER IRRADIATION

Lipid peroxidation (LPO) of liposomes photosensitized by hematoporphyr in derivatives (HPD) induced by low-intensity He - Ne laser irradiatio n (632,8 nm) was studied. The LPO was. estimated from the malondialdeh yde (MDA) formation in the thiobarbituric acid assay. Laser irradiatio n increased the levels of MDA in a dose-dependent manner (5-30 J/cm(2) ). The LPO of liposomes did not develop in the absence of HPD. Natural lipophilic antioxidants, such as alpha-tocopherol, licopin, and dihyd roquercetin, inhibited the LPO of liposome membranes more efficiently than a singlet-oxygen quencher sodium azide at the irradiation dose of 10,5 J/cm(2). It may be assumed that singlet oxygen generated in the membrane lipid phase is responsible for the LPO photosensitization by HPD in Liposomes upon laser irradiation.