Synthesis, DNA-binding, cytotoxicity, and cleavage studies of unsymmetrical oxovanadium complexes

Abstract

An unsymmetrical oxovanadium complex [VO(SAA)(phen)] (1) (SAA = salicylidene anthranilic acid, phen = phenanthroline) and its derivative [VO(MOSAA)(phen)] (2) (MOSAA = 2-hydroxy-4-methoxysalicylidene anthranilic) have been synthesized and characterized by elemental analysis, UV-Vis, ES-MS, IR, and ¹H NMR. The interaction of these two complexes with calf thymus DNA (CT-DNA) was investigated by absorption titration, fluorescence spectra, viscosity measurements, and thermal denaturation. Their photocleavage reactions with pBR322 supercoiled plasmid DNA were investigated by gel electrophoresis. The cytotoxicity of these two complexes against myeloma cell (Ag8.653) and gliomas cell (U251) have been assessed by MTT assay. The results show that both 1 and 2 bind to CT-DNA in classical intercalation, and the DNA-binding affinity of 1 is larger than that of 2. These complexes enhance the oxidative cleavage of supercoiled pBR322 DNA and both complexes have cytotoxic activities against Ag8.653 and U251 cell lines. Complex 1 has more potent inhibitory effect against the two cell lines than 2.

Keywords:

• Oxovanadium complexes
• DNA-binding
• Cytotoxicity
• Cleavage

Acknowledgments

We gratefully acknowledge financial support for this work by Guangdong Pharmaceutical University (No. 43540119), the National Key Research Project of China (No. 2011zx09102-001-31), and the National Natural Science Foundation of P.R. China (Nos 81102753 and 31070858).