Abstract:This study aims to optimize the ultrasonic-assisted extraction process of flavonoids from Zanthoxylum bungeanum leaves and evaluate their antibacterial activities. Single-factor tests were combined with an orthogonal design to study the effects of extraction temperature， extraction time， ethanol concentration， solid-toliquid ratio， ultrasonic power， and ultrasonic interval ratio on the yield of flavonoids. The extracted flavonoids were purified by macroporous resins， and the inhibitory activities of the flavonoids on Escherichia coli and Staphylococcus aureus were measured by the Oxford cup method. The results showed that the optimal conditions for ultrasonic-assisted extraction of flavonoids from Z. bungeanum leaves were extraction temperature of 40 ℃， extraction time of 25 min， ethanol concentration of 70%， solid-to-liquid ratio of 1∶30 （g/mL）， ultrasonic power of 300 W， and ultrasonic interval ratio of 9∶3， under which the yield of flavonoids was 14.93%，which was 42.9% higher than that of the control. The adsorption and desorption results of macroporous resins indicated that the AB-8 resin had a higher purification effect on Z. bungeanum leaf flavonoids. The purified flavonoids showed significant inhibitory activity against S. aureus， with a minimum inhibitory concentration of 0.4 mg/mL， while they demonstrated no significant inhibitory effect on E. coli.