Ruthenium(II)-arene complexes with dibenzoylmethane induce apoptotic cell death in multiple myeloma cell lines

A series of ruthenium(II) arene complexes (arene = p-cymene, hexamethylbenzene and benzene) containing dibenzoylmethane ligand (DBMH) of formula [(arene)Ru(DBM)Cl] and their ionic derivatives bearing PTA (1,3,5-triaza-7-phosphaadamantane), of formula [(arene)Ru(DBM)(PTA)]X (X = PF6- or SO3CF3-) have been synthesized and fully characterized. The solid-state structures of five complexes have been determined by single-crystal X-ray diffraction. These ruthenium materials exhibit intense photoluminescence emission at room temperature in the solid state. All complexes effectively bind to calf thymus DNA through intercalative/electrostatic interactions with more affinity for DNA minor groove. Finally, the antitumor activity of both ligand and complexes was evaluated against the U266 and RPMI human multiple myeloma cell lines, and some of them showed a cytotoxic and pro-apoptotic effect toward both cell lines.