Ruthenium(III) hydrazone complexes with triphenylphosphine/triphenylarsine co-ligands: Synthesis, DNA/BSA binding, antioxidative and cytotoxic activity

Abstract

New ruthenium(III) complexes with (E)-3-methoxy-N'-(phenyl(pyridin-2-yl)methylene) benzohydrazide (HL) have been synthesized and characterized by various physico-chemical and spectroscopic methods. The ligand acted as a tridentate, monobasic chelating ligand with NNO donor sites in all the complexes. The X-ray crystal structure of one of the complexes, [RuIII(L)(PPh3)Cl2] (1) demonstrated a distorted octahedral coordination geometry around the metal centre. Interactions of these complexes with calf thymus-DNA (CT-DNA) assessed by absorption and emission spectroscopy revealed intercalative mode of binding. Bovine serum albumin (BSA) binding of the ligand and complexes investigated by absorption spectroscopy, fluorescence and synchronous spectroscopic methods revealed that the compounds bind to BSA via static binding. Antioxidant study of the ligand and complexes showed significant antioxidant activity against DPPH radical. In addition, the in vitro cytotoxicity of the ligand and complexes against human breast cancer cell line (MCF-7) and human lung cancer cells (A-549) was assayed. The results showed higher cytotoxic activity with lower IC50 values indicating their efficiency in killing the cancer cells even at low concentrations.