Abstract: This study focused on evaluating the antibacterial activity of essential oils from Zanthoxylum schinifolium Siebold & Zucc. (ZSEOs) against Streptococcus mutans, Streptococcus sanguinis, and Streptococcus sobrinus. The essential oils were extracted from the pericarp of Z. schinifolium produced in four different areas of China (Chongqing, Guizhou, Sichuan, and Yunnan) by steam distillation and were designated as ZS1EO, ZS2EO, ZS3EO and ZS4EO, respectively and their chemical compositions were determined by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry (GC × GC-TOFMS). Meanwhile, the diameter of inhibition zone, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and growth curve of the cariogenic bacteria were measured to evaluate the antibacterial activity of ZSEOs. In addition, morphological changes in cariogenic bacteria after treatment with ZSEOs were determined by scanning electron microscopy (SEM). The results indicated that linalool (18.86%–22.00%), limonene (9.56%–14.84%), β-myrcene (5.79%–12.70%), sabinene (5.49%–8.93%) and β-pinene (3.33%–6.41%) were identified as the main components of the four ZSEOs. All ZSEOs showed inhibitory activity against the growth of S. mutans, S. sanguinis, and S. sobrinus, among which ZS1EO had the most potent antibacterial activity. The MIC and MBC of ZS1EO against the three cariogenic bacteria were 0.5–1.0 and 1–2 mg/mL, respectively. The growth of bacterial cells in the lag and exponential growth phases was stopped by treatment with ZS1EO at MIC concentration. The antibacterial activity of ZS1EO was related to the destruction of the bacterial chain structure and bacterial cell membrane damage. Collectively, this study highlights the potential used of ZSEOs as plant-derived anticariogenic agents.

Key words: Zanthoxylum schinifolium Siebold & Zucc.; essential oils; Streptococcus mutans; Streptococcus sanguinis; Streptococcus sobrinus; antibacterial activity