Experimental and theoretical investigations of cyclometalated ruthenium(ii) complex containing CCC-pincer and anti-inflammatory drugs as ligands: synthesis, characterization, inhibition of cyclooxygenase and in vitro cytotoxicity activities in various cancer cell lines

Abstract

The new cyclometalated ruthenium(II) complex, [Ru(CCC-Nap)(Ibu)(PTA)] was designed and synthesized using ibuprofen (Ibu), 1,3,5-triaza-7-phosphaadamantane (PTA) and CCC-pincer containing naproxen moiety (CCC-Nap) as ligands. The compounds were fully characterized by elemental analysis, FT-IR, multinuclear (¹H, ¹³C, and ³¹P) NMR spectroscopy, and electrospray ionization mass spectrometry. The cytotoxicity of the newly synthesized Ru(II) complex was found to be low, and the complex was about twice as active as cisplatin with IC₅₀ values in the range of 0.9–1.32 μM for both MCF-7 and MDA-MB-231 cell lines. Cyclooxygenase (COX) inhibition studies revealed that the Ru(II) complex displayed strong interactions with COX-2, about 16 and 5 times more than free Ibu and CCC-Nap ligands, respectively. The Ru(II) complex improved the production of reactive oxygen species (ROS) by 10.7 fold compared to the control (H₂O₂ as a positive control) in MCF-7 cells. Quantum chemical calculations gave more insights into the geometry and electronic properties of the novel Ru(II) complex, while molecular docking provided theoretical information on the interactions of Ru(II) complex with human cyclooxygenase-2 (COX-2) and the results were compared with those of the interactions of the free ligands with COX-2.