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

The copper complexes [Cu(Pyimpy)(H2O)](ClO4)2 (1), [Cu(Pyimpy)2](ClO4)2 (2), [Cu(Pyimpy)(Cl)2]·2H2O (3·2H2O), [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 CuCl2·2H2O 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.

Some new copper complexes were synthesized and characterized by spectroscopic and electrochemical studies. The molecular structures of representative complexes were determined by X-ray crystallography. Generation of new species during DNA interaction by the novel copper(II) complexes was revealed. The superoxide scavenging activity, oxidative DNA cleavage and the cytotoxicity of these complexes were examined.Figure optionsDownload as PowerPoint slideHighlights
► Copper complexes derived from tridentate ligand were synthesized.
► Complexes were characterized spectroscopically and by X-ray crystallography.
► Redox properties and SOD activity were examined.
► DNA binding and nuclease activity were investigated.
► Cytotoxicity of the complexes on MCF-7, PC-3 and HEK-293 cells was determined.