Phenolic profiling and corrosion-inhibiting potential of the methanolic extract of Helichrysum italicum ssp. italicum (Corsica): Eco-friendly natural products for sustainable development

The phenolic constituents of Helichrysum italicum ssp. italicum were extracted using ethyl acetate and methanol and characterized by LC–MS/MS, revealing thirteen compounds, mainly flavones, phenolic derivatives, and organic acids such as chlorogenic, ferulic, and caffeic acids. The methanolic extract (MeOH extract) was evaluated for its effect on the corrosion behavior of mild steel in 1 M HCl using weight loss measurements, showing significant inhibition efficiency that increased with extract concentration but decreased with temperature. This inhibition was attributed to the physical adsorption of phenolic molecules on the steel surface, consistent with the Langmuir adsorption isotherm. DFT and DFTB simulations further confirmed the strong adsorption interaction, while Petra/Osiris/Molinspiration (POM) analysis supported compliance with Lipinski’s Rule of Five and provided insights into the bioactivity and drug-likeness of the natural compounds. The combined experimental and computational findings reveal that these natural products possess dual functionality, acting as effective mixed-type corrosion inhibitors and potential pharmacological agents with possible antibacterial, antifungal, and antiviral activities.