Ni(II) complexes with non-steroidal anti-inflammatory drug diclofenac: Structure and interaction with DNA and albumins

The interaction of nickel(II) with the non-steroidal anti-inflammatory drug sodium diclofenac (Nadicl) in the presence of the N,N′-donor heterocyclic ligands 2,2′-dipyridylketone oxime (Hpko), 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen) leads to the formation of mononuclear Ni(II) complexes. The crystal structure of [Ni(dicl)(Hdicl)(Hpko)2](dicl)·CH3OH·0.6H2O (1·CH3OH·0.6H2O) has been determined by X-ray crystallography. The interaction of the complexes with human or bovine serum albumins has been studied by fluorescence spectroscopy revealing their good binding affinity to the albumins with high binding constant values. UV study of the interaction of the complexes with calf-thymus DNA (CT DNA) has shown that the complexes can bind to CT DNA with [Ni(dicl)(Hdicl)(Hpko)2](dicl) exhibiting the highest binding constant to CT DNA. Complex 1 can bind to CT DNA via intercalation as concluded by studying its cyclic voltammograms in the presence of CT DNA solution and by DNA solution viscosity measurements, while for complexes [Ni(dicl)2(bipy)] (2) and [Ni(dicl)2(phen)] (3) a non-classic intercalative mode has been concluded. Competitive studies of the complexes with ethidium bromide (EB) have shown their moderate to significant ability to displace the DNA-bound EB suggesting a competition with EB.

The mononuclear nickel(II) complexes of the non-steroidal anti-inflammatory drug diclofenac in the presence of N,N′-donor ligands exhibit pronounced binding behaviour towards DNA and serum albumins compared to the free drug.Figure optionsDownload as PowerPoint slide