Synthesis, characterization, DNA interaction, and in vitro 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.

Graphical Abstract

Keywords:

• Synthesis
• Ru(II) complex
• DNA-binding
• Photocleavage
• Cytotoxicity

Additional information

Funding

Funding. We are grateful to the National Natural Science Foundation of China [grant number 21101034], Yong Teachers Training Plan of Guangdong Province [grant number Yq2013086], Science and Technology Plan of Dongguan City [grant number 2011108102046], and innovative item of undergraduate of Guangdong Province [grant number 1057112037].