Synthesis, characterization, DNA interaction, and antitumor activities of mixed-ligand metal complexes of kaempferol and 1,10-phenanthroline/2,2'-bipyridine

Four novel mixed-ligand metal complexes with the composition [Cu(Kae)(phen)]Cl center dot 2H(2)O (1), [Cu(Kae)(bpy)]Cl center dot H2O (2), [Zn(Kae)(phen)]Cl center dot H2O (3), and [Zn(Kae)(bpy)]Cl center dot H2O (4), where Kae = kaempferol, phen = 1,10-phenanthroline, bpy = 2,2'-bipyridine were synthesized and characterized by elemental analysis, IR, UV, H-1 NMR, C-13 NMR, HRMS ,and molar conductivity. The binding and cleavage abilities of complexes 1-4 with DNA have been studied by fluorescence spectroscopy, viscosity measurements, and gel electrophoresis under physiological conditions. The experimental results indicated that four complexes could bind to CT-DNA via an intercalative mode, and the complex 1 showed the strongest activity to cleavage DNA (pUC 19). The in vitro cytotoxicities of kaempferol and complexes 1-4 were also evaluated against human breast carcinoma cells by MTT assays. The results show that the cytotoxicities of complexes 1-4 are much higher than that of kaempferol alone, and the complex 1 shows the strongest ability to inhibit the growth of human breast carcinoma cells. The results suggest that the complex 1 may be a valuable tool in cancer chemotherapy agents.