Palladium(II) Complexes with Thiosemicarbazones. Syntheses, Characterization and Cytotoxicity against Breast Cancer Cells and Anti-Mycobacterium tuberculosis Activity

Three Pd(II) complexes were prepared from N(4)-substituted thiosemicarbazones: [Pd(aptsc)(PPh(3))](NO(3))center dot H(2)O, 1, [Pd(apmtsc)(PPh(3))](NO(3)), 2, and [Pd(apptsc)(PPh(3))](NO(3))center dot H(2)O, 3, where PPh(3) = triphenylphosphine; Haptsc = 2-acetylpyridine-thiosemicarbazone; Hapmtsc = 2-acetylpyridine-N(4)-methyl-thiosemicarbazone and Happtsc = 2-acetylpyridine-N(4)-phenyl-thiosemicarbazone. All complexes were characterized by elemental analysis, IR, UV-Vis, (1)H and (31)P{(1)H} NMR spectroscopies, and had their crystalline structures determined by X-ray diffractometry from single crystals. The monoanionic thiosemicarbazonate ligands act in a tridentate mode, binding to the metal through the pyridine nitrogen, the azomethine nitrogen and the sulfur atoms. The cytotoxic activity against the breast cancer cell line MDA-MB231 and the anti-Mycobacterium tuberculosis H(37)Rv ATCC 27294 activity were evaluated for the compounds. All Pd(II) complexes were highly active against the studied cell line, presenting similar values of IC(50), around 5 mu mol L(-1), while the clinically applied antitumor agent cisplatin was inactive. The compounds show remarkable anti-M. tuberculosis activities, presenting MIC values comparable or better than some commercial anti-M tuberculosis drugs.