Ruthenium (II) complexes containing a new asymmetric ligand: DNA interaction, photocleavage and topoisomerase I inhibition

A new asymmetric ligand 2-(pyridine-2-yl)-1-H-imidazo[4,5-g]acenaphtho[1′,2′:2,3]quinoxaline (piaq) and its ruthenium complexes with [Ru(L)2(piaq)]2+ (L = bpy (2,2′-bipyridine), phen (1,10-phenanthroline)), have been synthesized, and their DNA-binding, photocleavage and DNA topoisomerase I inhibition properties were measured. Results suggested that both Ru(II) complexes can intercalate into DNA base pairs. Furthermore, the two complexes are efficient DNA-photocleavers under irradiation at 365 nm, and singlet oxygen (1O2) is the active specie in DNA photocleavage. Topoisomerase inhibition and DNA strand passage assay suggested that both complexes are efficient inhibitors of DNA topoisomerase I.

Two Ru(II) complexes, [Ru(bpy)2(piaq)]2+(1) and [Ru(phen)2(piaq)]2+(2), have been synthesized and characterized. The experiment results suggest that two complexes are efficient DNA-photocleavers and inhibitors of DNA topoisomerase I.Figure optionsDownload as PowerPoint slideHighlights
► Two ruthenium complexes with asymmetric ligand have been synthesized.
►  These complexes can bind to DNA through intercalation.
►  Complexes are efficient DNA-photocleavers and inhibitors of DNA topoisomerase I.