Synthesis and Characterization of Piano-Stool Ruthenium(II)-Arene Complexes of Isatin Schiff Bases: Cytotoxicity and DNA Intercalation.

A series of aryl-isatin Schiff base derivatives ( 3a - d ) and their piano-stool ruthenium complexes ( 4a - d ) were synthesized and characterized via 1 H and 13 C NMR and Fourier transform infrared (FTIR) spectroscopy. In addition, the purity of all of the compounds ( 3a - c and 4a - d ) was determined via elemental analysis. Complex 4d was analyzed using X-ray crystallography. An in vitro antiproliferative study of the compounds ( 3a - c and 4a - d ) against human hepatocellular carcinoma (HEPG2), human breast cancer (MCF-7), human prostate cancer (PC-3), and human embryonic kidney (HEK-293) cells exhibited their considerable antiproliferative activity. 4d exhibited effective cytotoxicity against HEPG2 and MCF-7. It displayed higher cytotoxicity than the reference metallo-drug cisplatin. Moreover, the stability of 4d was studied via 1 H NMR spectroscopy, and the binding model between 4d and DNA was investigated via ultraviolet-visible spectroscopy. The lipophilicity of the synthesized complexes was determined using an extraction method.