DNA interaction, antioxidant and in vitro cytotoxic activities of some mononuclear metal(II) complexes of a bishydrazone ligand

A tridentate ONO donor bishydrazone ligand, 3-(((3-oxoindolin-2-ylidene)hydrazono) methyl)quinoxalin-2(1H)-one (L) was synthesized. Using the ligand, mononuclear metal complexes of the type [M(L)(OAc)] (M = Co(II), Ni(II), Cu(II) and Zn(II), OAc = -OCOCH3) were synthesized. The newly synthesized compounds were thoroughly characterized by various analytical and spectral techniques. Tetrahedral geometry was proposed for Co(II), Ni(II) and Zn(II) complexes, while square planar geometry has been assigned to the Cu(II) complex. The in vitro antibacterial, antifungal and antioxidant studies reveal that the Cu(II) complex of the bishydrazone ligand possess higher activities. DNA binding studies suggest that the present compounds interact with CT DNA through intercalation. This was further supported by molecular docking. Gel electrophoresis studies substantiated the involvement of free radicals in the cleavage of pUC18 DNA. In vitro cytotoxicity of the compounds against MCF-7 cell line was also examined. The molecular modeling studies reveal that the compounds strongly interact with VEGFR-2 kinase receptor through hydrogen bonding, pi-pi, pi-cation and sigma-pi interacdons. The bioavailability and bioactivity determination of the compounds suggest that the present compounds may be utilized as drug candidates. (C) 2017 Elsevier B.V. All rights reserved.