Multi-target antibacterial mechanism of eugenol and its combined inactivation with pulsed electric fields in a hurdle strategy on Escherichia coli

Abstract Eugenol (2-Methoxy-4-(2-Propenyl) Phenol; EUG) is a natural antibacterial ingredient of the essential oil from many aromatic plants. The antimicrobial mechanism of EUG and its combined inactivation effect with pulsed electric fields (PEF) treatment in a hurdle strategy on E. coli ATCC 8739 were investigated. Results showed that membrane integrity and the morphology of E. coli cell were damaged and the membrane permeability was increased when E. coli was exposed to higher levels of EUG. Analysis of fluorescence spectra, molecular docking and atomic force microscope indicated that EUG bound to the AT-rich region of DNA through groove binding mode, leading to morphological alterations and the aggregation of DNA molecules. The combinations of EUG and PEF demonstrated strong synergistic effects for sterilization and it was proven to be an effective method to achieve a higher level of E. coli inactivation.