Antimicrobial activity of carvacrol-MPTES adducts prepared via thiol-ene photochemistry grafted onto silica against Escherichia coli and Listeria monocytogenes.

Abstract

Immobilization of antimicrobial compounds onto solid surfaces has recently emerged as a promising strategy to control microbial growth in food systems. However, conventional immobilization methods often require high energy input and large amounts of organic solvents, which may negatively impact the environmental sustainability of the process. As a greener alternative, this work proposes a solvent-free photocatalyzed reaction between allylcarvacrol derivatives and (3-mercaptopropyl)triethoxysilane (MPTES), producing the corresponding MPTES-carvacrol adducts used for surface grafting. The resulting materials exhibited clear antimicrobial activity against Escherichia coli and Listeria monocytogenes. Notably, only the compound retaining a free hydroxyl group was active against both strains, achieving a reduction of 98.39% for L. monocytogenes and 99.02% for E. coli, confirming the essential role of this functional group. These findings demonstrate that the sustainable strategy developed here provides an effective and eco-friendly approach for immobilizing bioactive antimicrobial compounds, contributing to safer and more sustainable food preservation systems.