DNA photocleavage, topoisomerase I inhibition, and cytotoxicities of two ruthenium complexes containing asymmetry ligand

ABSTRACT In recent years, ruthenium (II) complexes have attracted attention due to high DNA topoisomerase I inhibitory activities and good anticancer activities. Herein, an asymmetric ligand 2-(5-(1, 10-phenanthroline))-1 H-4,5-diphenyl-imidazole (pdpi) and its ruthenium complexes were synthesized. DNA-binding mode of two complexes was determined as intercalation by using UV–vis spectra, emission spectra, viscosity, and molecular docking experiments. DNA photocleavage experimental results show that two ruthenium complexes effectively cleave plasmid DNA by producing singlet oxygen. Furthermore, they both displayed good topo I inhibition activities. The cytotoxic activities results show that complex 2 displays better antitumor activities against Eca-109 cells and A549 cells (IC 50 = 25.97 ± 3.33 μM and 28.83 ± 2.49 μM, respectively) compared to complex 1 .