Abstract:In order to optimize the extraction process of total coumarins from Ficus hirta and clarify its in vitro antioxidant activity, this paper took the extraction rate of total coumarins as the evaluation standard, and investigated the effects of ethanol volume fraction, liquid material ratio and ultrasonic time on the extraction rate of total coumarins from Ficus hirta by single factor experiment. The ultrasonic-assisted extraction process of total coumarins from Ficus hirta was optimized by Box-Behnken experimental design, and the in vitro antioxidant activity of the total coumarins extracted by the optimized extraction process was studied. The results showed that the optimum extraction conditions were as follows: ethanol volume fraction 58 %, liquid-solid ratio 34:1, ultrasonic extraction time 70 min. Under this condition, the average extraction yield of total coumarins from Ficus hirta was 3.869 mg/g under these conditions, RSD was 0.28 %, which was basically consistent with the predicted value of 3.884 mg/g. The in vitro antioxidant activity was also investigated, which showed that the IC50 values of total coumarins from Ficus hirta were 2.23 mg/mL and 0.33 mg/mL for DPPH free radicals and ABTS free radicals, respectively. The extraction process optimized by response surface methodology is simple and feasible. The total coumarins extracted from Ficus hirta has strong antioxidant activity and can be used as a natural antioxidant source for further development and comprehensive application.