DNA interaction, superoxide scavenging and cytotoxicity studies on new copper(II) complexes derived from a tridentate ligand

Abstract

The copper complexes [Cu(Pyimpy)(H 2O)](ClO 4) 2 ( 1), [Cu(Pyimpy) 2](ClO 4) 2 ( 2), [Cu(Pyimpy)(Cl) 2]·2H 2O ( 3·2H 2O), [Cu(Pyimpy)(N 3)(ClO 4)] 2 ( 4) and [Cu(Pyimpy)(SCN)(ClO 4)] 2 ( 5) were synthesized and characterized by spectroscopic techniques, crystal structures and electrochemical studies (Pyimpy: (2-((2-phenyl-2-(pyridin-2-l)hydrazono)methyl)pyridine)). The superoxide scavenging activity of the two water soluble complexes 1 and 3 was examined. DNA interaction studies by UV–Vis absorption spectral changes during a titration experiment indicated the generation of new species. These small molecule SOD mimics exhibited excellent DNA cleavage activity in the presence of H 2O 2 as well as 2-mercaptoethanol. Complexes 1– 5 exhibited better cytotoxicity compared to CuCl 2·2H 2O and the ligand Pyimpy, and showed more potency than cisplatin for MCF-7, PC-3 and HEK-293 cells. Complex 3 exhibited the highest potency for MCF-7, PC-3 and HEK-293 cells compared to the other complexes.