Natural and synthetic porphyrins in acetone solution or incorporated in lipid vesicle membranes. Photosensitization of singlet oxygen and of the methyl red—ascorbate oxidation—reduction

Abstract

Several natural and synthetic porphyrins in acetone—water solutions photosensitize the formation of singlet oxygen (haematoporphyrin, pheophytins, chlorophylls and palladium octaethyl, palladium tetraphenyl and palladium tetrapropyl porphyrins). When they are embedded in lipid vesicle (liposome) membranes, these same molecules photosensitize their disruption presumably through the formation of singlet oxygen. In similar liposome membranes, chlorin E6 and its methyl ester, haematoporphyrin, pheophytins and palladium octaethyl and palladium tetrahexyl porphyrins photosensitize the reduction of methyl red by ascorbate. However, the reduction appears to be reversed by singlet oxygen.