Synthesis, structural elucidation, and in vitro antiproliferative activities of mixed-ligand titanium complexes

Mixed-ligand titanium complexes have been synthesized by reacting titanium tetrachloride (TiCl4), benzoylacetone (bzac), and respective bidentate ligands [2,2'-bipyridine (bipy), 4,4'-dimethyl-2,2'-bipyridine (bpme), 4,4'-dimethoxy-2,2'-bipyridine (bpome), 6,6'-dimethyl-2,2'-bipyridine (dpme)], in 1:1:1 molar ratios, respectively. The structure of synthesized complexes was confirmed by different spectroscopic techniques like FT-IR, UV-Visible, NMR (H-1 and C-13), and mass spectrometry. The complexes were analyzed for antiproliferative potential in HeLa (cervical), C6 (glioma), and Chinese hamster ovarian (CHO) cell lines, and their effect was seen on different stages of the cell cycle only in CHO cells by using fluorescent propidium iodide. It was observed that all the four synthesized complexes exhibited potent cytotoxic activity toward Hela cancer cell line. The antiproliferative activity of complex TiCl2(bzac)(bpme) was found to be stronger against Hela with an IC50 value of 3.3 mu M and weaker against C6 cell line having IC50 value of 141.7 mu M. The flow cytometric analysis indicated that the complexes inhibited cell proliferation and increased in hypo diploid cells, which confirms to some extent the cell death via apoptosis.