Evaluation of bioactive compounds in <i>Lysimachia arvensis</i> extract through in vitro cytotoxicity, density functional theory, non-covalent interaction analyses, and molecular dynamics simulations

<i>Lysimachia arvensis</i> (L.) U. Manns & Anderb. is a medicinal plant traditionally used for various therapeutic purposes; however, its bioactive properties and potential toxicological effects remain insufficiently characterized. This study aimed to investigate the biological activity, cytotoxic potential, phytochemical composition, and molecular interaction mechanisms attributed to exposure to methanolic extract of <i>L. arvensis</i> using integrated <i>in vitro</i> and <i>in silico</i> approaches. The methanolic extract exhibited antioxidant activity with a DPPH radical scavenging IC₅₀ value of 88.59 ± 23.29 mg/ml, and demonstrated strong 71% xanthine oxidase inhibition. Total flavonol, flavonoid, phenolic, and tannin contents were determined to be 25.33 mg QE/g, 16.55 mg QE/g, 23.18 mg GAE/g, and 0.91 mg GAE/g extract, respectively. GC-MS analysis identified 17 compounds, with guanosine, quinic acid, methyl linolenate, and myo-inositol as predominant constituents. Cytotoxicity assays demonstrated marked toxicity of the extract toward HEK293 cells with an IC₅₀ value of 17.47 μg/mL, indicating significantly higher cytotoxicity compared to methanol alone. Molecular docking identified guanosine as the strongest binder to human erythrocyte catalase (PDB ID: 1DGF) with a binding energy of -8.6 kcal/mol, followed by neophytadiene and a pyran derivative. Molecular dynamics simulations over 100 ns confirmed stability of protein-ligand complexes while revealing ligand-specific mobility patterns. DFT and NCI analyses noted strong hydrogen-bonding interactions and distinct electronic properties among key compounds. Overall, <i>L. arvensis</i> exhibits notable bioactivity associated with significant cytotoxicity indicating the need for careful safety risk assessment.