Antimony(III) complexes with 2-benzoylpyridine-derived thiosemicarbazones: Cytotoxicity against human leukemia cell lines

The antimony(III) complexes [Sb(2Bz4DH)Cl2] (1), [Sb(H2Bz4M)Cl3]·2H2O (2) and [Sb(2Bz4Ph)Cl2] (3) were obtained with 2-benzoylpyridine thiosemicarbazone (H2Bz4DH) and its N(4)-methyl (H2Bz4M) and N(4)-phenyl (H2Bz4Ph) derivatives. H2Bz4DH, H2Bz4Ph and complexes (1–3) exhibited high cytotoxic activity against HL-60 and Jurkat human leukemia cell lines. When these compounds were tested against HL-60 cells with ectopic expression of BcrAbl, Bcl-2 or Bcl-XL, which confer resistance to apoptosis against a variety of death-inducing agents, the cytotoxicity was much lower, indicating apoptosis to be part of their mechanism of action. The cytotoxic activity of complexes 2 and 3 against HL-60 and Jurkat cells was significantly higher than that of the corresponding thiosemicarbazones, suggesting coordination to be an interesting strategy of cytotoxic dose reduction.

Graphical abstract[Sb(2Bz4DH)Cl2] (1), [Sb(H2Bz4M)Cl3] (2) and [Sb(2Bz4Ph)Cl2] (3) were obtained with 2-benzoylpyridine thiosemicarbazone (H2Bz4DH) and its N(4)-methyl (H2Bz4M) and N(4)-phenyl (H2Bz4Ph) derivatives. H2Bz4DH, H2Bz4Ph and 1–3 were highly cytotoxic to leukemia cells.Figure optionsDownload full-size imageDownload as PowerPoint slide