Oxidative DNA cleavage, cytotoxicity and antimicrobial studies of l-ornithine copper (II) complexes

New ternary copper (II) complexes, Cu(l-orn)(B)(Cl)(Cl·2H 2O) (1-2) where l-orn is l-ornithine, B is an N,N-donor heterocyclic base, viz. 2,2â²-bipyridine (bpy, 1) and 1,10-phenanthroline (phen, 2), were synthesized and characterized by various spectroscopic techniques. Complex 2 is characterized by the X-ray single crystallographic method. The complex shows a distorted square-pyramidal (4 + 1) CuN 3OCl coordination sphere. Binding interactions of the complexes with calf thymus DNA (CT-DNA) were investigated by UV-Vis absorption titration, ethidium bromide displacement assay, viscometric titration experiment and DNA melting studies. Complex 2 shows appreciable chemical nuclease activity in the presence of 3-mercaptopropionic acid (MPA). The complexes were subjected to in vitro cytotoxicity studies against carcinomic human alveolar basal epithelial cells (A-549) and human epithelial (HEp-2) cells. The IC 50 values of 1 and 2 are less than that of cisplatin against HEp-2 cell lines. MIC values for 1 against the bacterial strains Streptococcus mutans and Pseudomonas aeruginosa are 0.5 mM. © 2012 Elsevier Ltd. All rights reserved