Dipyridophenazine complexes of cobalt(III): DNA photocleavage and photobiology

Abstract

The UV-visible spectroscopy and photochemistry of [Co(en) 2(DPPZ)](ClO4)3 (DPPZ = dipyrido[3,2-a:2′,3′-c]-phenazine) in the presence of plasmid DNA and the nucleoside 2′-deoxygaunosine have been investigated. Evidence for the intercalation of the complex with DNA and photoinduced DNA strand breakage is found. The structurally related complexes [Co(en)2(DPPN)]Cl 3 and [Co(en)2(DPPA)]Cl2, where DPPN = benzo[i]dipyrido[3,2-a:2′,3′-c] phenazine and DPPA = dipyrido[3,2-a:2′,3′-c]phenazine-11-carboxylic acid, have also been synthesized and characterized. In vitro cytotoxicity studies and photocytotoxicity studies of the complexes using the C6 rat glioma cell line are reported and indicate signific..