Diimine Platinum(II) and Palladium(II) Complexes of Dithiocarbamate Derivative as Potential Antitumor Agents: Synthesis, Characterization, Cytotoxicity, and Detail DNA-Binding Studies

The synthesis and chemical characterization of two structurally related platinum(II) and palladium(II) complexes, [M(2 2'-bipyridine)(morpholinedithiocarbamate)]NO3 or [M(bpy) (mor-dtc)]NO3, where M = Pt(II) or Pd(II), are descried. Studies of anti-tumor activities of these complexes against human cell tumor lines (K-502) have been carried out. They show 50% cytotoxic concentration (Cc(50)) values much lower than that of cisplatin. Both of these water soluble complexes have been shown to interact with calf thymus DNA (ct-DNA) using difference absorption-, fluorescence-, and circular cichroism-titration techniques. These studies showed that both complexes exhibit cooperative binding and presumably intercalate in DNA. These complexes unexpectedly denature DNA at very low concentrations (50-100 mu M). Several binding and thermodynamic parameters ere also described.