Selenium nanoparticles enhance secondary metabolite accumulation, antioxidant defense, and antimicrobial activity in Echium italicum: a study supported by molecular docking analysis

Italian viper’s bugloss (Echium italicum L.), one of the important plants of the Boraginaceae family, is a rich source of shikonin derivatives. Selenium nanoparticles (Se NPs) are an effective tool for enhancing plant growth and promoting the accumulation of secondary metabolites in medicinal plants. This study examined the effects of Se NPs concentrations (0, 5, 10, and 20 mg/L) on E . italicum , focusing on biomass production, photosynthetic performance, antioxidant responses, shikonin, antibacterial, and multi-ligand docking of shikonin. Se NP treatments enhanced shoot and root biomass, chlorophyll index, total phenolic and flavonoid content, DPPH and FRAP antioxidant activity, phenylalanine ammonia-lyase (PAL) activity, and antioxidant enzyme levels. The highest shikonin accumulation was observed at 10 mg/L, with an 84.5% increase compared to the control. Antimicrobial activity of leaf and root extracts was evaluated against Escherichia coli , Salmonella enterica , and Staphylococcus aureus , with the strongest inhibition observed against S. aureus . To elucidate the antioxidant and antibacterial properties of the identified molecules, used molecular docking, a computational approach that predicts the binding of small molecules to proteins. Molecular docking indicated shikonin binding affinities to microbial enzymes. Overall, the findings of this study demonstrate that Se NPs significantly enhance biochemical attributes and modulate the physiological functions of E. italicum .