Copper(II) complexes with non-steroidal anti-inflammatory drugs and neocuproine: Structure and biological evaluation

Four novel copper(II) complexes with the non-steroidal anti-inflammatory drugs tolfenamic acid (Htolf), mefenamic acid (Hmef), naproxen (Hnap) and sodium diclofenac (Na dicl) were prepared in the presence of the N, N'-donor neocuproine (neoc) as co-ligand and were characterized by physicochemical and spectroscopic techniques. The complexes bear the formulas: [Cu(tolf)2(neoc)] (complex 1), [Cu(mef)2(neoc)] (complex 2), [Cu (nap)2(neoc)] (complex 3) and [Cu(dicl)2(neoc)] (complex 4), respectively. Single-crystal X-ray crystallography was employed to determine the crystal structure of complex [Cu(tolf)2(neoc)]. The in vitro scavenging activity of the complexes against 1,1-diphenyl-picrylhydrazyl and 2,2 '-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) free radicals and the ability to reduce H2O2 were studied in the context of the antioxidant activity studies. The compounds interact with calf-thymus DNA via intercalation, as indicated by UV-vis spectroscopy and DNA-viscosity titration studies, and competitive studies with ethidium bromide. Additionally, the complexes were checked for their binding affinity to bovine serum albumin by fluorescence emission spectroscopy, and demonstrated significant and reversible binding to the albumin.