Dark and Photoinduced Cytotoxicity of Cationic Chlorin e6 Derivatives with Different Numbers of Charged Groups

Dark and photoinduced toxicity of several novel and previously described derivatives of chlorin e6 with tetraalkylammonium substituents differing from each other in number of cationic groups and their location in the macrocycle were studied in HeLa cells and mammalian erythrocytes. The optimal design of cationic derivatives of chlorin e6 that provides the most efficient photodynamic effect was shown to require the localization of cationic substituents in the same part of the molecule. In combination with the hydrophobicity of the chlorin macrocycle, it increases the amphiphilic properties of the whole molecule and enhances its interaction with biomembranes.