Synthesis, characterization, DNA interaction, and <i>in vitro</i> cytotoxicity activities of two ruthenium(II) complexes with disubstituted 2,2′-dipyridyl ligands bearing ammonium groups

Abstract

The DNA binding, cleavage, and cytotoxic properties of two new Ru(II) complexes [Ru(bpy)2L](PF6)4 (L: L1 = (5,5′-((n-Me)3NCH2)2-bpy)2+; L2 = (5,5′-((n-Et)3NCH2)2-bpy)2+) have been investigated. The results show that both Ru(II) complexes bind to DNA through an electrostatic binding mode. The binding affinity constant can reach 104 M−1 and 1 has a higher binding affinity than 2. Equilibrium dialysis experiments revealed that the complexes are candidates for enantioselective binding to CT-DNA. Moreover, further analysis of the ruthenium complexes revealed that 1 has a higher and more efficient DNA cleavage activity than 2. In vitro cytotoxicity studies of both complexes showed that they exhibited moderate antitumor activity against HeLa, A549, and CNE-2 cancer cells. In addition, 2 displayed higher in vitro cytotoxicity than 1.