Abstract: In this study, essential oil (WLEO) from wampee leaves was extracted by steam distillation, and its chemical composition was analyzed using gas chromatography-mass spectrometry (GC-MS). The results showed that WLEO was mainly composed of sesquiterpene alcohols and sesquiterpene hydrocarbons. Subsequently, its inhibitory effects and underlying mechanisms against Streptococcus mutans and its biofilms were systematically evaluated. It was demonstrated that WLEO exhibited significant inhibitory effects against S. mutans, with an inhibition zone diameter of (22.33 ± 0.74) mm. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined to be 2.5 and 5 mg/mL, respectively. The bacterial growth curve further confirmed that WLEO effectively inhibited bacteria growth at the MIC. Crystal violet staining and XTT assays showed that WLEO significantly reduced the total biomass and metabolic activity of S. mutans biofilms. Furthermore, WLEO suppressed biofilm formation by inhibiting extracellular polysaccharide synthesis. Membrane potential analysis and live/dead fluorescence staining revealed that WLEO disrupted the integrity of the bacterial cell membrane, resulting in the leakage of intracellular components. Untargeted metabolomics analysis further revealed that WLEO exerted its antibacterial activity by interfering with lipid metabolism, energy metabolism and other related metabolic pathways. Collectively, these results suggest that WLEO inhibits the growth and biofilm formation of S. mutans through a synergistic multitarget mechanism, providing a theoretical basis for its potential application in the food and related fields.

Key words: wampee leaf essential oil; Streptococcus mutans; biofilm; antibacterial mechanism