Synthesis and photodynamic activity of new imidazole substituted pyropheophorbide-a derivatives

Two new imidazole substituted chlorin derivatives, namely (4-[1-imidazolyl]-phenyl)-amide pyropheophorbide-a and (3-[1-imidazolyl]-propyl)-amide pyropheophorbide-a have been synthesized. Their cell viabilities on A549 human lung adenocarcinoma cells were investigated and compared with that of pyropheophorbide-a. According to the phototoxicity study, (4-[1-imidazolyl]-phenyl)-amide pyropheophorbide-a and (3-[1-imidazolyl]-propyl)-amide pyropheophorbide-a were found superior to pyropheophorbide-a with respect to high phototoxicity. This work demonstrates that imidazole substituted chlorin derivatives could be a promising candidate for photodynamic therapy and are worth further investigations.