Mechanistic Insight for Targeting Biomolecules by Ruthenium(II) NSAID Complexes

With the enormous progress in ruthenium complexes as promising anticancer agents after the entry of KP1019, KP1339, and NAMI-A in clinical trials, herein three arene ruthenium(II) NSAID (nonsteroidal anti-inflammatory drugs) complexes viz. [Ru(η⁶-p-cymene)(mef)Cl] (1), [Ru(η⁶-p-cymene)(flu)Cl] (2), and [Ru(η⁶-p-cymene)(dif)Cl] (3) are synthesized, characterized, and reported. Density functional theory (DFT) calculations were performed in support of the obtained experimental results by computing the equilibrium geometries, reactions pathways, relative Gibbs free energy, stability, and reactions barriers of the complexes. The present theoretical study shows that all the proposed structures of the complexes are energetically stable and favorable, and the results obtained are in close accordance with the experiment. Further, the in vitro cytotoxicity of the complexes was explored through MTT assay on MCF-7, Hela, A549, and HEK cell lines. It was found the complex 1 and 2 are significantly cytotoxic toward the MCF-7 cell line. These complexes have also shown a strong affinity toward CT-DNA and proteins (HSA and BSA) as analyzed through spectroscopic techniques. Further investigation of the mechanism of cell death of selected complexes was carried out by various staining, flow cytometry, and gene expression analysis obtained by RT-PCR.