Abstract: 【Objective】To determine the optimal conditions for ultrasound-assisted ethanol extraction of perilla leaf total flavonoids and to evaluate their antibacterial and antioxidant activities.【Methods】After determining the optimal conditions for each factor through single-factor experiments,response surface methodology was employed to design the extraction process optimization experiment,and the optimal extraction conditions for perilla leaf total flavonoids were determined using Design-Expert 13.0. The antibacterial capacity was assessed using the inhibitory effect on Staphylococcus aureus as an indicator,while antioxidant activity was evaluated through DPPH and ABTS free radical scavenging assays.【Results】Under different factor levels,the extraction yields of perilla leaf total flavonoids reached the highest values of 2.72%,3.20%,2.76%,and 3.02%,respectively,with the ethanol volume fraction of 35%,liquid-to-solid ratio of 15:1（mL:g）,ultrasonic power of 300 W,and extraction time of 30 min. After optimization using response surface methodology,the extraction yield of perilla leaf total flavonoids reached a maximum of （3.375±0.098）% under the conditions of 36% ethanol volume fraction,liquid-to-solid ratio of 17:1（mL:g）,ultrasonic power of 303 W,and extraction time of 33 min. The obtained perilla leaf total flavonoids extract exhibited a significant inhibition zone against Staphylococcus aureus,with maximum DPPH and ABTS free radical scavenging rates of 97.86% and 95.79%,respectively.【Conclusion】The optimal extraction conditions for perilla leaf total flavonoids are an ethanol volume fraction of 36%,liquid-to-solid ratio of 17:1（mL:g）,ultrasonic power of 303 W,and extraction time of 33 min. The perilla leaf total flavonoids demonstrate significant inhibitory effects against Staphylococcus aureus and strong free radical scavenging capacity.

Key words: Perilla leaf total flavonoids, Response surface methodology, Extraction process, Antibacterial activity, Antioxidant activity