Synthesis and pharmacological activities of some mononuclear Ru(II) complexes

A series of mononuclear Ru(II) complexes of the type Ru(M)2(U)]2+, where M = 2,2'-bipyridine/1,10-phenanthroline and U = tpl (Ru1), 4-Cl-tpl (Ru2), 4-CH3-tpl (Ru3), 4-CH3O-tpl (Ru4), and 4-NO2-tpl (Ru5), -pai (Ru6), where tpl = thiopicolinanilide and pai = 2-phenyl-azo-imidazole, have been prepared and characterized by IR, UV-Vis, 1H NMR, 13C-NMR, FAB-Mass spectrophotometer, and elemental analysis. The complexes display metal-ligand charge transfer (MLCT) transitions in the visible region. The title complexes were subjected to in vivo anticancer activity tests against a transplantable murine tumor cell line, Ehrlich's ascitic carcinoma (EAC) and in vitro antibacterial activity against Gram positive and Gram negative microorganisms. Ru1-Ru6 were found to increase the life span of the tumor hosts by 19-52%, and decreased tumor volume and viable ascitic cell count. The results of the present study clearly demonstrated the tumor inhibitory activity of the ruthenium chelates against transplantable murine tumor cell line. The treatment with ruthenium complexes could be secondary to tumor regression or due to the action of the compounds itself. The significant antibacterial activity was observed for Ru1-Ru4 against microorganisms like Vibrio cholera 865, Staphylococcus aureus 6571, and Shigella flexneri as compared to that of standard drug chloramphenical. Ru5 showed moderate activity against S. aureus 8530. However, all the complexes fail to show significant antibacterial activity against V. cholera 14033 and Shigella sonnai.