Physicochemical Studies and Anticancer Potency of Ruthenium η6-p-Cymene Complexes Containing Antibacterial Quinolones

With the aim of exploring the anticancer properties of organometallic compounds with bioactive ligands, Ru-(arene) compounds of the antibacterial quinolones nalidixic acid (2) and cinoxacin (3) were synthesized, and their physicochemical properties were compared to those of chlorido(e-p-cymene) (ofloxacinato-kappa O-2,O) ruthenium (II) (1). All compounds undergo a rapid. ligand exchange reaction from chlorido to aqua species. 2 and 3 are significantly more stable than 1 and undergo minor conversion to an unreactive [(cym)Ru(mu-OH)(3)Ru-(cym)](+) species (cym = eta(6)-p-cymene). In the presence of human serum albumin 1-3 form adducts with this transport protein within 20 min of incubation. With guanosine 5'-monophosphate (5'-GMP; as a simple model for reactions with DNA) very rapid reactions yielding adducts via its N7 atom were observed, sllustrating that DNA is a possible target for this compound class. A moderate capacity of inhibiting tumor cell proliferation in vitro was observed for 1 in CH1 ovarian cancer cells, when as 2 and 3 turned out to be inactive.