Synthesis, cancer cell antiproliferative and antibacterial activity of zinc hydroxybenzoate complexes of substituted terpyridines

Terpyridine metal complexes are well known for their wide range of biological activities, among which the anticancer effect has received increasing attention. In this paper, nine zinc terpyridine complexes were synthesized by using zinc o/m/p-hydroxybenzoate and three 4 '-(substituted phenyl)-2,2 ':6 ',2 ''-terpyridine ligands, and the structures of these complexes were characterized by elemental analysis, infrared spectroscopy, single crystal X-ray diffraction,1. In order to study their antiproliferative activities, four cell lines were selected for in vitro cellular experiment: human esophageal cancer cell line (Eca-109), human breast cancer cell line (MCF-7), human hepatocellular carcinoma cell (Bel -7402) and human normal liver cells (HL -7702). The results show that they possess standout inhibitory effect on the proliferation activity against the cancer cells but less cytotoxicity to normal cells, being superior to cisplatin, a commonly used drug in clinical practice. Bacteriostatic experiment also shows that most complexes have a good inhibitory effect on Staphylococcus aureus, with the minimum bacteriostatic concentration is as low as 20 mu g/mL. The strong affinity between these complexes and CT-DNA was verified by UV spectrum, and the main binding mode of intercalation was found by circular dichroism. Molecular docking study reveals that these complexes bind to the double-stranded DNA mainly by intercalation, giving the binding capacity sequence as ATAT < GCGC. And they bind to G-quadruplex mainly through electrostatic force, with the binding capacity of 2A5R > 2KKA > 1CN0.