Synthesis and structure of [(η6-p-cymene)Ru(2-anthracen-9-ylmethylene-N- ethylhydrazinecarbothioamide)Cl]Cl; biological evaluation, topoisomerase II inhibition and reaction with DNA and human serum albumin

We have synthesized and evaluated the biological properties of a compound of the type [eta(6)-p-cymene)Ru(EtATSC)Cl]Cl (1) where EtATSC = 2-anthracen-9-ylmethylene-N-ethylhydrazinecarbothioamide, a thiosemicarbazone. The complex has been characterized by elemental analysis, spectroscopically (NMR, UV-Vis, and IR) and structurally by XRD. The in vitro anticancer activity of 1 has been evaluated against two human colon cancer cell lines. The IC50 value for activity against HCT-116 was 224 +/- 7 mu M and 205 +/- 5 mu M against the Caco-2 cell line. The proficiency of 1 as an antibacterial agent was also evaluated against six bacterial strains. The minimum inhibitory concentration for Bacillus cereus was determined to be 5 mu M and for Enterococcus faecalis it was 20 mu M. At the maximum concentration tested the complex showed no activity against the Gram-negative strains. The complex binds strongly to human serum albumin with a binding constant of 1.37 +/- 0.02 M-1 at 308 K on a single binding site. It is also a strong binder to DNA with an apparent binding constant of 2.82 x 10(5) M-1 at 308 K. 1 shows very good activity as a catalytic inhibitor of human topoisomerase II at concentrations as low as 20 mu M.