Synthesis, Characterization, Antitumor Properties, DNA-Interaction and Effect of Electrical Charges Present on Different Ratios of Pd(II):Zn(II) Complexes in Their "Combination Therapy"

A modified literature procedure was used for synthesis [Pd(bpy)2](NO3)2, Pd(II), (where: bpy is 2,2'-bipyridine ligand) and a new zinc complex of formula K[Zn(Gly)3], Zn(II), (where: Gly is glycinato ligand). These two complexes have been characterized by elemental analysis, conductivity measurements and spectroscopic techniques such as FT-IR, 1H NMR, and UV-Vis. Pd(II) complex alone and in presence of 1, 2 and 3 molar ratio of Zn(II) complex have been tested against Chronic myelocytic leukemia K562 cell lines. They show growth suppression activity. Thus calf thymus DNA-binding studies using UV-Vis methods were carried out. The results indicate that probably the planar aromatic moiety of the Pd(II) complex cooperatively intercalate in DNA and presence of Zn(II) complexes impede the intercalation by an unknown mechanism. The impeding properties of Zn(II) complex increases by increasing the ratio of Pd(II):Zn(II) ongoing from 1:1, 1:2 to 1:3. This might be due to the decrease in positive charges of the above mixtures ongoing from 1:1, 1:2 to 1:3 ratio (f. 1). We found no such an effect in the literature. In the process of the interaction studies, several binding and thermodynamic parameters were investigated.These parameters may be used to predict DNA-binding mechanism in the series.