Antibacterial Activity of Fructus forsythia Essential Oil and the Application of EO-Loaded Nanoparticles to Food-Borne Pathogens

Fructus forsythia essential oil (FEO) with excellent antibacterial activity was rarely reported. The objective of the present study was to investigate the antibacterial activity and the antibacterial mechanism of FEO against two food-borne pathogenic bacteria, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in vitro. When treated FEO, the zones of inhibition (ZOI) of E. coli (20.5 ± 0.25 mm) and S. aureus (24.3 ± 0.21 mm) were much larger than control (p < 0.05). The minimum inhibitory concentrations (MICs) of FEO were 3.13 mg/mL and 1.56 mg/mL for E. coli and S. aureus, respectively. The antibacterial mechanism of FEO against E. coil was due to the changes in permeability and integrity of cell membrane leading to the leakage of nucleic acids and proteins. With the superior antibacterial activity of FEO, the nano-encapsulation method has been applied in FEO. When compared to FEO and blank chitosan nanoparticles, FEO-loaded nanoparticles (chitosan to FEO of 1:1) can effectively inhibit the growth of E. coil above 90% at room temperature. It is necessary to consider that FEO and FEO-loaded nanoparticles will become promising antibacterial additives for food preservative, cosmetic, and pharmaceutical applications.