The in vitro antitumor activity of oligonuclear polypyridyl rhodium and iridium complexes against cancer cells and human pathogens

Abstract

Synthesis, characterization and biological activity of mono, bi and tri nuclear pentamethylcyclopentadienyl rhodium and iridium complexes with 1,3,5-tris(di-2-pyridylaminomethyl)benzene (L) ligand have been described. These complexes have general formula [(Cp*MCl)nL]n+ {M = Rh; n = 1 (1), n = 2 (2), n = 3 (3); M = Ir; n = 1 (4), n = 2 (5), n = 3 (6)} and have been characterized by various spectroscopic techniques. Crystal structure of the complexes 1, 2 and 4–6 has been obtained by single crystal X-ray diffraction analyses. The electronic transition and orbital occupation of complexes have been rationalized by density functional theory studies. The comparative abilities of bacterial inhibition and antiproliferative activity of complexes 1–6 towards four human pathogens (Staphylococcus aureus MTCC96; Escherichia coli MTCC739; Klebsiella pneumonia MTCC2653 and Pseudomonas aeruginosa MTCC2453) and four cancerous cells {B16F10 (Mouse melano carcinoma), THP-1 (human acute monocytic leukemia), PC3 (Human prostate carcinoma) and SK-OV-3 (Human ovarian carcinoma)} have been investigated by agar well diffusion method and MTT assay respectively. An in vitro cytotoxicity study of the complexes (2 and 3) found significant activity against B16F10 and THP-1 cancer cell lines. The structure-activity relationship on aforementioned cancer cell lines indicates that rhodium complexes are more active than iridium complexes.