Mixed ligand complexes of Cu(II)/Zn(II) ions containing (m-)/(p-) carboxylato phenyl azo pentane 2,4-dione and 2,2′-bipyridine/1,10 phenanthroline: Synthesis, characterization, DNA binding, nuclease and topoisomerase I inhibitory activity

Abstract

Abstract Metal complexes of type [Cu(L1H)2(bpy)] (1), [Zn(L1H)2(bpy)] (2), [Cu(L2H)2(bpy)] (3) and [Cu(L2H)2(Phen)] (4) (L1H2 = 3-[N′-(1-acetyl-2-oxo-propylidene)-hydrazino]-benzoic acid, L2H2 = 4-[N′-(1-acetyl-2-oxo-propylidene)-hydrazino]-benzoic acid, bpy = 2,2′-bipyridine, Phen = 1,10 phenanthroline) are synthesized and characterized using spectroscopic techniques (FT-IR, 1H NMR, 13C NMR, electronic absorption and emission) and elemental analysis data. The assembly of the complexes involving intramolecular H-bonding is displayed using corresponding crystal structure. Binding of the complexes separately with Calf Thymus DNA is monitored using UV-vis spectral titrations. The displacement of ethidium bromide (EB) bound to DNA by the complexes, in phosphate buffer solution (pH ∼ 7.2) is monitored using fluorescence spectral titrations. Nuclease activity of the complexes follow the order 4 > 3 > 1 > 2. The gel electrophoretic mobility assay measurement in presence of minor groove binder 4′,6-diamidino-2-phenylindole (DAPI), suggests that complexes preferably bind with the minor groove of DNA. Topoisomerase I inhibitory activity of the complexes 3 and 4 inhibit topoisomerase I activity with IC50 values of 112 and 87 μM respectively. © 2015 Elsevier B.V.