Abstract
This study investigated the antimicrobial activity and underlying inactivation mechanisms of Quercus phillyraeoides essential oil (QP-EO) against Staphylococcus aureus. Results of the disk diffusion assay demonstrated the potent antimicrobial activity of QP-EO (zone of inhibition, 11.97-12.08 mm). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of QP-EO against S. aureus was 1.25 mg/mL, indicating its potential bactericidal properties. This similar MIC and MBC values suggests that QP-EO induces irreversible damage at specific concentrations. In addition, transmission electron microscopy revealed that QP-EO induces cell shape distortion and cell wall rupture in S. aureus, which may be caused by the small essential oil particles. QP-EO also significantly inhibited S. aureus initial biofilm formation and reduced the cell mass of preformed biofilms, suggesting its potential in controlling biofilm-associated infections. These findings highlight the efficacy of QP-EO as a natural antimicrobial and antibiofilm agent, with implications for microbial control and food safety. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-025-01949-1.