Synthesis, cytotoxicity and DNA binding of novel Ni(II), Co(II) and Zn(II) complexes bearing pyrimidinyl hydrazone ligand

•Three novel complexes 1–3 were synthesized and successfully characterized.•The in vitro cytotoxicity of complexes 1–3 was evaluated against selected cell lines.•Complex 3 is a promising and multi-targeting antiproliferative agent.•Complex 3 induced BGC-823 cell apoptosis in a dose-dependent manner.•Complex 3 interacts with DNA via partial intercalation. To develop efficient new antitumor agents, Ni(II), Co(II) and Zn(II) complexes 1–3 derived from 2-((2-pyrimidin-2-yl)hydrazono)methyl)quinoline (HL) were prepared and structurally characterized using IR, elemental analysis, UV-Vis, fluorescence spectrometry and single crystal X-ray diffraction analysis. The in vitro cytotoxicity of complexes 1–3 against MCF-7, BGC-823, A549, BEL-7402 tumor cell lines and human normal cell line HL-7702 was evaluated using MTT assay. Complexes 1-3 display higher cytotoxic activity than cisplatin as well as HL against BGC-823 tumor cell line, with IC50 values ranging from 5.57 µM to 11.20 µM, and less toxicity toward the normal cell line HL-7702. In particular, complex 3 exhibits the most prominent antiproliferative activity. Complex 3 was found to induce apoptosis of BGC-823 cells greatly in a dose-dependent manner, which was suggested by Annexin V-FITC/PI and AO/EB dual-staining assays. The DNA binding studies, which were performed using UV-Vis, fluorescence and CD spectral analyzes, revealed that complex 3 interacts with CT-DNA mainly via a partial intercalative binding mode. The molecular docking of the interaction of complex 3 with DNA is in accordance with the experimental data. [Display omitted]