Highly cytotoxic iron(II) complexes with pentadentate pyridyl ligands as a new class of anti-tumor agents

The iron(II) complexes 1a and 2 with pentadentate pyridyl ligands are stable under physiological conditions and exhibit higher cytotoxicities toward a series of human carcinoma cell lines than cisplatin; 1a can significantly increase intracellular oxidant levels, cleave supercoiled plasmid DNA in vitro without addition of a reductant and induce apoptotic cell death in human cervical epithelioid carcinoma cells (HeLa) as observed in flow cytometric studies.