Cytotoxicity evaluation and DNA binding studies of 1,3-dihydroxy-2-(4-methoxyphenyl)-4,5-dimethyl-1H-imidazol-3-ium chloride beyond its structural and Hirshfeld surface analysis, spectroscopic investigations, vibrational assignments and theoretical characterizations

Abstract

1,3-Dihydroxy-2-(4-methoxyphenyl)-4,5-dimethyl-1H-imidazol-3-ium chloride (DMPDI) was synthesized via a solvent-free protocol and characterized. Crystallographic analyzes reveal that the crystal cation, as a result of steric hindrance, is not planar; the imidazole ring system has a dihedral angle of 44.62° with the plane of the anisole group. The molecule was also optimized using the density functional theory formalism, with the B3LYP functional and 6-31G+(d,2p) basis set. The computationally simulated IR, Raman, and NMR spectra were compared with the corresponding experimental data and detailed frequency assignments were performed. Additionally, frontier molecular orbitals (FMO), molecular electrostatic potential (MEP), and nonlinear optical (NLO) properties were calculated using density functional theory (DFT) methods. Evaluation of the antiproliferative activity of the compound revealed potent anticancer activity with IC₅₀ values of 458.6 µM (124.18 µg/mL) and 645.7 µM (174.78 µg/mL) performed in vitro with A-549 lung cancer and SKOV-3 ovarian cancer cell lines, respectively. The compound was found to be less toxic to the normal hepatic cell line (WRL-68). The selectivity index (SI) of the compound was calculated and found to be 2.5 and 1.8 for A-549 and SKOV3, respectively. Molecular docking studies with human Topoisomerase I (PDB ID: 1RRJ) were carried out to assess binding affinity and investigate the possible mechanism behind the observed anticancer effect. Preliminary binding studies with calf thymus DNA (CT-DNA) by absorption titration and displacement studies with ethidium bromide revealed that DMPDI effectively binds via groove binding. For the theoretical investigation of DNA binding interactions, docking studies of DMPDI with B-DNA dodecamer (PDB ID: 1BNA) were carried out to validate the experimental results.