Optimization of ultrasonic microwave synergistic extraction of total flavonoids from longan shell by response surface method

The effect of the ultrasound-microwave synergistic method on the extraction ratio of total flavone from longan shell was studied and the extraction conditions were optimized by using response surface analysis method. The results showed that the optimum conditions for extracting total flavone were:ultrasonic power 100 W, ratio of liquid to solid material 29.2:1 mL/g, ethanol concentration 50%, extraction temperature 57℃, and extraction time 5 min. Under this condition, the extraction rate of total flavone was 3.06%. Compared with ultrasound-or microwave-extraction method, this one was more timesaving and had higher extraction rate, which was suitable for extracting flavonoids from longan shell.