Photosensitization with benzochlorin iminium salts

摘要

Abstract: The photobiology of a group of iminium salts was examined. The nonfluorescent copper derivative (CDS1) had an almost undetectable triplet yield, but could catalyze phototoxic effects in cell culture and experimental animal tumors, apparently without the involvement of singlet oxygen. The Zn analog and the metal-free iminium salt both exhibited fluorescence, and were somewhat more efficacious that CDS1, perhaps because both type I and type II processes were available. The nonfluorescent Ni analog was inactive as a photosensitizer. Fluorescent probes indicated that CDS1 and its zinc analog catalyzed photodamage at mitochondrial loci, the metal-free derivative at membrane loci. Because of its very low fluorescence yield, the metal-free iminium salt showed only faint intracellular fluorescence, but the Zn analog was unusual in this regard, with irradiation leading to a photoproduct with very intense intracellular fluorescence which was not readily photobleached. !11