Synthesis, characterization and in vitro anticancer, DNA binding and cleavage studies of Mn (II), Co (II), Ni (II) and Cu (II) complexes of Schiff base ligand 3‐(2‐(1‐(1H‐benzimidazol‐2‐yl)ethylidene)hydrazinyl)quinoxalin‐2(1H)‐one and crystal structure of the ligand

Abstract

A Schiff base ligand, 3‐(2‐(1‐(1H‐benzimidazol‐2‐yl)ethylidene)hydrazinyl)quinoxalin‐2(1H)‐one (BZHQO), has been synthesized by the condensation of 3‐hydrazinylquinoxalin‐2(1H)‐one and 1‐(1H‐benzoimidazol‐2‐yl) ethanone and characterized using spectral and single‐crystal X‐ray analyses. Mn (II), Co (II), Ni (II) and Cu (II) complexes of the BZHQO ligand have been synthesized and characterized. The interactions of the ligand and its metal complexes with calf thymus DNA have been investigated using absorption spectroscopy and the intrinsic binding constant has been evaluated. Agarose gel electrophoresis has been performed to study the abilities of the ligand and its metal complexes to cleave supercoiled pBR322 DNA into nicked circular form. In vitro anticancer activities of the Cu (II) and Ni (II) complexes have been investigated by MTT assay, using the cell lines HeLa, B16‐F10, SKOV3 and MCF7. The Cu (II) complex has been found to be active against HeLa, B16‐F10 and MCF7, while the Ni (II) complex has been found to be active against MCF‐7.