Novel Zn(II) complexes with non-steroidal anti-inflammatory ligand, flufenamic acid: Characterization, topoisomerase I inhibition activity, DNA and HSA binding studies.

A series of new Zn(II) complexes with flufenamic acid (flu) has been synthesized, namely [Zn(dmso)(flu)] (1), [Zn(flu)(py)] (2), [Zn(flu)(tmen)] (3), [ZnCl(flu)(neo)] (4), and [Zn(cyclam)(flu)] (5), where py=pyridine, tmen=N,N,N',N'-Tetramethylethylene diamine, neo=2,9-Dimethyl-1,10-phenanthroline and cyclam=1,4,8,11-Tetraazacyclotetradecane. These complexes have been characterized by infrared spectroscopy, single-crystal X-ray structure analysis, elemental and thermal analysis. All complexes contain deprotonated flufenamic acid coordinated via carboxylato group to zinc atoms, but their structures differ in the carboxylato binding mode, the coordination number of the central atom, the shape of the coordination polyhedra and the resultant supramolecular structures. Furthermore, an interaction of complexes with calf-thymus DNA (CT DNA) and human serum albumin (HSA) has been investigated by spectroscopic techniques. Moreover, the complexes 1 and 2 inhibit the catalytic activity of topoisomerase I at 60μM.