Synthesis, properties, antitumor and antibacterial activity of new Pt(II) and Pd(II) complexes with 2,20-dithiobis(benzothiazole) ligand

Abstract Mono- and binuclear Pt(II) and Pd(II) complexes with 2,2′-dithiobis(benzothiazole) (DTBTA) ligand are reported. [Pt(DTBTA)(DMSO)Cl]Cl∙CHCl 3 ( 1 ) and [Pd 2 (µ-Cl) 2 (DTBTA) 2 ]Cl 2 ( 2 ) have been synthesized and structurally characterized by elemental analysis, IR, 1 H and 13 C NMR spectroscopy, MS spectrometry and the content of platinum and palladium was determined using a flame atomic spectrometer. Two different coordination modes of 1 and 2 complexes were found; in both complexes, the coordination of Pt(II) and Pd(II) ions involves the N(3) atoms of the ligand but the binuclear complex 2 , is a cis- chloro-bridged palladium complex. Evaluation of their in vitro antitumor activity against two human tumor cell lines human breast cancer (MCF-7) and hepatocellular carcinoma (HepG2); and their antimicrobial activity against Escherichia coli and Kokuria rhizophila was performed. Only complex 1 showed a dose- and time-dependent cytotoxic activity against the two tumor cell lines, associated to apoptosis and accumulation of treated cells in G0/G1 phase of cell cycle, while both 1 and 2 exhibited antimicrobial activity with complex 1 much more potent. The study on intracellular uptake in both MCF-7 and HepG2 cell lines revealed that only platinum of complex 1 is present inside the cells, suggesting a different mode of action of the two compounds. This was also in agreement with the results obtained for the antitumor and antibacterial activity.