Abstract:In order to determine the optimum extraction process of total flavonoids from Hibiscus tilisceus leaves and evaluate its antioxidant activity，the extraction process of total flavonoids from Hibiscus tilisceus leaves was optimized using response surface methodology.With the extraction yield of total flavonoids as the target，the single factor experiment was investigated involving ethanol concentration，liquid to material ratio，extraction temperature and extraction time as factor.Four factors and three levels response surface methodology were established based on the Box-Behnken design and the antioxidant activities were also obtained.The results showed that the quadratic polynomial regression model was extremely significant （p＜0.000 1），which could be used to analysis and predict the extraction yield of total flavonoids from Hibiscus tilisceus leaves.The optimal extraction conditions were as follow：ethanol concentration 64%，liquid material ratio 27∶1（mL/g），extraction temperature 76 °C and extraction time 93 min.The extraction yield of total flavonoids from Hibiscus tilisceus leaves was 28.35 mg/g on the optimal condition，and the relative error was 0.46%compared with the predicted value （28.48 mg/g）.The use of response surface method to optimize the extraction process of total flavonoids from Hibiscus tilisceus leaves had the accuracy and reliability，and the total flavonoids obtained had a strong antioxidant activity.