Abstract:The present study investigated the effects of electron beam irradiation on the extraction efficiency and activity of quinones from walnut green husk and explored the antibacterial activity and antioxidant activity of different organic extraction phases（petroleum ether phase，dichloromethane phase，and ethyl acetate phase）.The optimal extraction conditions were determined by response surface methodology（RSM）.Antibacterial activity was evaluated by the inhibition zone size of Bacillus cereus，Escherichia coli，Salmonella，and Staphylococcus aureus by the Oxford cup method，and antioxidant activity was evaluated by scavenging rate of DPPH·，ABTS＋·，and·OH.The results showed that electron beam irradiation pretreatment could increase the yield of quinones from walnut green husk and suitable radiation dose was 30 kGy.The optimum extraction conditions were as follows:ethanol concentration of 65% ，material-to-liquid ratio of 1∶40（g/mL），and ultrasonic time of 170 min.Under above conditions，the yield of quinones reached 8.35 mg/g.The different extraction phases of the green husk extract showed certain antioxidant activity and antibacterial activity.The ethyl acetate extract possessed the strongest antioxidant activity，and the scavenging rates of DPPH·，ABTS+·，and·OH reached 95.8% ，70.7% ，and 27.7% respectively.Meanwhile，ethyl acetate extract also showed strong antibacterial activity against E.coli，S.aureus，and Salmonella，and the diameters of the inhibition zone reached（13.81±0.42）mm，（11.70±0.32）mm，and（12.86±0.85）mm respectively.Electron beam irradiation coupled with ultrasound-assisted extraction could enhance the extraction efficiency of quinones from walnut green husk，and potentiate the antibacterial and antioxidant activities of active compounds，which had broad application prospects in the extraction of natural products.