Optimizing ultrasonic-assisted extraction of saponins from Coreopsis tinctoria by response surface methodology

Saponins in Coreopsis tinctoria were extracted with distilled water under the assistance of ultrasonic,and the extraction process was optimized by using response surface analysis based on Box-Behnken design to examine the effects of extraction conditions including liquid-to-material ratio,length of ultrasonic treatment time and extraction temperature on saponins yield,which were reflected by a quadratic regression model.The results showed that the optimal extraction conditions were: material-to-liquid ratio 1∶21(g∶mL),ultrasonic treatment time 29min and extraction temperature 61℃.Under these conditions,the saponins yield was 7.57%.