Synthesis, characterization, and biological activity of a new palladium(II) complex with deoxyalliin

Synthesis, characterization, and biological activity of a new water-soluble Pd(II)–deoxyalliin (S-allyl- L -cysteine) complex are described in this article. Elemental and thermal analysis for the complex are consistent with the formula [Pd(C 6 H 10 NO 2 S) 2 ]. 13 C NMR, 1 H NMR, and IR spectroscopy show coordination of the ligand to Pd(II) through S and N atoms in a square planar geometry. Final residue of the thermal treatment was identified as a mixture of PdO and metallic Pd. Antiproliferative assays using aqueous solutions of the complex against HeLa and TM5 tumor cells showed a pronounced activity of the complex even at low concentrations. After incubation for 24 h, the complex induced cytotoxic effect over HeLa cells when used at concentrations higher than 0.40 mmol/L. At lower concentrations, the complex was nontoxic, indicating its action is probably due to cell cycle arrest, rather than cell death. In agreement with these results, the flow cytometric analysis indicated that after incubation for 24 h at low concentrations of the complex cells are arrested in G0/G1.Key words: palladium(II), deoxyalliin, S-allyl- L -cysteine, tumor cells, cancer.