Manganese(II) Complexes with Non-Steroidal Anti-Inflammatory Drugs: Structure and Biological Activity

Nine manganese(II) complexes with a series of non-steroidal anti-inflammatory drugs (namely sodium diclofenac, diflunisal, flufenamic acid, sodium meclofenamate, mefenamic acid, and tolfenamic acid) were prepared in the presence of diverse nitrogen donors, i.e., pyridine, 1,10-phenanthroline, 2,2'-bipyridine and neocuproine, as co-ligands and were characterized with spectroscopic techniques and single-crystal X-ray crystallography. The biological profile of the resultant complexes was investigated regarding their antioxidant potency and their interaction with DNA and serum albumins. The complexes interact with calf-thymus DNA in an intercalative mode and bind tightly and reversibly to human and bovine serum albumins studied. In order to assess the antioxidant activity of the Mn(II) complexes, their ability to scavenge 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) free radicals was monitored.