Synthesis, characterization and in vitro anticancer studies of Ru(III) dithiocarbamate complexes

We report the synthesis, spectroscopic characterization and in vitro cytotoxic evaluation of five ruthenium(III) dithiocarbamate complexes. Spectroscopic data indicated that the Ru(III) complexes were isolated as six-coordinate octahedral complexes in which each ruthenium(III) is coordinated to three molecules of dithiocarbamato anions as bidentate chelating ligands. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was used to evaluate the cytotoxic activity of the ruthenium(III) dithiocarbamate complexes against human embryonic kidney (HEK293) and cervical cancer (HeLa). The Ru(III) complexes showed moderate cytotoxic activity towards HEK293 and HeLa cells, but the activity was a bit higher in HEK293 cells compared with HeLa cells. Tris(piperidinedithiocarbamato)ruthenium(III) (1) showed the highest activity in both cell lines with IC50 values of 6.4 and 30.29 µM for both HEK293 and HeLa cells, respectively. Four of the compounds consist of a phenyl ring and they all show IC50 values above 50 µM. These results proved that the cytotoxic activity of the compounds is influenced by the nature of the ligand coordinated to the ruthenium(III) ion.