Ruthenium(II) arene complexes with 1,8-naphthalimide-type ligands: synthesis, characterization and biological evaluation.

Considering the known biological potential of Ru(II) arene compounds with N-donor ligands, two Ru(II) complexes (Ru1 and Ru2) of the type [RuCl₂(ɳ⁶-p-cymene)(L)], where L1 = 6-(piperidin-1-yl)-2-(pyridin-4-yl)-1H-benzo[de]isoquinoline-1,3(2H)-dione and L2 = 6-(morpholin-1-yl)-2-(pyridin-4-yl)-1H-benzo[de]isoquinoline-1,3(2H)-dione were synthesized and characterized by ¹H and ¹³C NMR spectroscopies. The complexes had their antitumoral profiles evaluated against several cell lines, such as Hep-G2 (liver) and MDA-MB-231 (breast) cell lines, but were inactive towards all the tested lines. Additionally, Ru2 and L2 were evaluated as Jack Bean Urease inhibitors, and were found to be potent inhibitors of this enzyme, with higher inhibition percentages (Ru2 - 64.4%; L2 - 13.9%) than the standard inhibitor thiourea (5.1%). Since the activity of Ru2 was five times higher than its free ligand L2, it is concluded that coordination to a Ru(II) arene center is a good strategy to improve anti-ureolytic potential.