Synthesis and characterization of novel Ru(III) complexes of 2‐aminopyrazine: Interaction with biomolecules, antineoplastic activity, and computational investigation

Abstract

Ruthenium (III) complexes (1–3) of 2‐aminopyrazine (pyz) with general formula of [Hpyz][RuCl4(DMSO)(pyz)](1), Na[RuCl4(pyz)(DMSO)] (2), and (Hpyz)[RuCl4(pyz)2].2H2O (3) have been synthesized and characterized by elemental analyses, FTIR, 1H NMR, and UV–visible spectroscopy, along with the magnetic susceptibility and cyclic voltammetry measurements. The molecular structures of the complexes have also been optimized using density functional theory (DFT) calculation which demonstrates an octahedral geometry to be adopted by the Ru(III) ion. The UV–visible and fluorescence spectra were employed to study the interaction of the compounds with nucleic acid (ctDNA and tRNA) and bovine serum albumin (BSA). The data showed a higher tendency for the ligand and its complexes (1–3) to interact with biomolecules (1 > 2 > 3). All complexes showed potent in vitro anticancer activity against three human cancer cell lines and high safety against normal cell lines as complex (1) is the most active one, it was selected for the flow cytometric evaluation for cell death mode, cell cycle analysis, and matrix metalloproteinase‐9 (MMP9) expression in treated MDA‐231 cells. Proliferating cell nuclear antigen (PCNA) expression and VEGF concentration were evaluated in the treated cells and compared with the untreated ones. Our study proved that complex (1) arrests the cell cycle, inhibits DNA transcription, reduces both MMP9 (validated by our molecular docking investigation targeting MMP9 protein) and PCNA expressions, and induces apoptotic cell death, leading to cancer metastasis prevention.