XueWen Liu,Jie Huang,YuXuan Tang,YouMing Shen,JiLin Lu
A new polypyridyl ligand containing a nitro group and two new ruthenium complexes of it were synthesized. The two complexes exhibited non-dppz DNA ‘light switch’ effects after interaction with calf thymus DNA. Introducing both electron-withdrawing group (─ NO 2 ) and electron-donating group (─ CH 3 ) may be the reason that the two complexes display DNA ‘light switch’ behaviors. Furthermore, one of the complexes showed higher photocleavage activity, topoisomerase I inhibition activity and DNA affinity than the other. The present work shows that the more active complex can be employed as a non-dppz DNA ‘light switch’, DNA photocleaver and topoisomerase I inhibitor. In addition, the two complexes have no or weak cytotoxic activities against Eca-109 and A549 cells.
Xue-Wen Liu,Yang Xiao,Wei-Gen Peng,Li-Jin Zhao,You-Ming Shen,Song-Bai Zhang,Ji-Lin Lu
Two ruthenium complexes containing a new ligand phipz (phipz = 2-(1,10-phenanthroline)-1H-imidazo[4,5-b]phenazine) were designed and synthesized. These complexes were found to inhibit the DNA supercoiled relaxation mediated by topoisomerase I (topo I), cleave DNA under irradiation and bind to calf thymus DNA through intercalative mode. Furthermore, complex 2 shows higher photocleavage activity, topo I inhibition activity and DNA affinity than complex 1 . Additionally, introduction of phenazine unit may be the reason that two complexes exhibit DNA ‘light switch’ behavior. The present work shows that two complexes might be potential as new DNA ‘light switches’, DNA photocleavers and topo I inhibitors.
Xue-Wen Liu,Ning-Yi Liu,Yuan-Qing Deng,Shan Wang,Ting Liu,Yu-Cai Tang,Yuan-Dao Chen,Ji-Lin Lu
Ruthenium(II) complexes containing phenazine ring have attracted attention to design as ‘molecular light switches’. In this study, we synthesized two ruthenium complexes containing phenazine ring and studied their abilities to function as DNA intercalators, DNA ‘light switches’, DNA topo I inhibitors, DNA photocleavers and potential antitumor reagents. [Ru(bpy)2(mbipz)](PF6)2 (1) (bpy = 2,2′-bipyridine, mbipz = 2-(4′-methyl-bipyridine-4-yl)-1H-imidazo[4,5-b]phenazine) exhibited off–on type DNA ‘light swtich’ behavior. DNA binding modes of the two complexes were determined as intercalation by using UV–vis spectra, emission spectra, viscosity and molecular docking experiments. DNA photocleavage experimental results showed that the two ruthenium complexes effectively cleave plasmid DNA by producing singlet oxygen. Furthermore, they displayed good topo I inhibition activities. We further found that the two complexes displayed good antitumor activities against Eca-109 cells and A549 cells. The results demonstrated that introduction of phenazine ring will be helpful to design DNA ‘light switch’ based on ruthenium complex.Communicated by Ramaswamy H. Sarma