Optimization of ultrasonic assisted alcohol extraction process of flavonoids from Radix Astragali by response surface methodology

Response surface methodology was used to optimaize the ultrasonic assisted alcohol extraction of flavonoids from Radix Astragali. On basis of single factor experiment, optimize the ethanol concentration, solidliquid ratio, extraction temperature, and ultrasonic time which influence the yield of flavonoids. The optimum technological conditions were determined as follows :the ethanol concentration 60%, solid-liquid ratio 1 ∶20 (g∶m L) , extraction temperature 76℃, ultrasonic time 30 min, and the flavonoids yield was 3.30%.