7. Platinum(II) and Palladium(II) complexes with 1,10-phenanthroline and pyrrolidinedithiocarbamato ligands: synthesis, DNA-binding and anti-tumor activity in leukemia K562 cell lines

Two newly-created water-soluble complexes of palladium(II)/platinum(II)-dithiocarbamate, [Pd/Pt(phen)(pyr-dtc)]NO3 (phen = 1,10-phenanthroline and pyr-dtc = pyrrolidinedithiocarbamate) were synthesized. Also, their chemical characteristics are reported in the current research paper. In these complexes, the dithiocarbamato ligand coordinates to Pt(II) or Pd(II) center with two sulfur atoms as bidentate. They were examined for their cytotoxic properties against chronic myelocytic leukemia K562 cell lines. These complexes showed 50% cytotoxic concentration (Cc50) values much lower than those of cisplatin. The interactions of the two complexes with calf thymus DNA (CT-DNA) were investigated using UV-vis absorption, fluorescence emission, ethidium bromide displacement and gel filtration techniques. The results suggest that these complexes cooperatively bind with and denature the DNA at low concentrations and interact with CT-DNA in the intercalation mode. Gel filtration studies indicate that the binding of complexes with DNA is strong enough not to break readily.