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

The copper complexes [Cu(Pyimpy)(H2O)](ClO4)2 (1), [Cu(Pyimpy)2](ClO4)2 (2), [Cu(Pyimpy)(Cl)2]2H2O (32H2O), [Cu(Pyimpy)(N3)(ClO4)]2 (4) and [Cu(Pyimpy)(SCN)(ClO4)]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 H2O2 as well as 2-mercaptoethanol. Complexes 1–5 exhibited better cytotoxicity compared to CuCl22H2O 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.