Abstract: In order to optimize extraction of total flavonoids from Hovenia acerba and investigate xanthine oxidase inhibitory activity.Based on the results of single-factor tests,the ratio of liquid to solid,extraction time and ethanol concentration were optimized by response surface analysis.The results showed that the process of optimum extraction were the ratio of liquid to solid of 15:1 (mL:g),ethanol concentration of 53%,extraction time of 1.85 h.Under these conditions,the extraction yield of total flavonoids was 2.56%,which was close to the predicted value.The total flavonoid (TF) was further purified by D101 macroporous resin and evaluated for its xanthine oxidase (XO) inhibitory activities in vitro,and the results showed that TF possessed significant enzyme inhibitory action with IC₅₀ value of 18.63 ± 1.67 μg/mL.These results indicated that the optimized extraction technology was reliable and provided a reference for further development and utilization of the Hovenia acerba.

Key words: Hovenia acerba, flavonoid, response surface methodology, xanthine oxidase