Optimization of total flavonoids extraction from mulberry leaves by response surface methodology

Using local mulberry leaves as raw material,flavonoids in mulberry leaves were extracted with ultrasonic assisted extraction technology using ethanol as solvent.Effects of ethanol concentration,solid-liquid ratio,ultrasonic time,ultrasonic temperature on the extraction rate were studied.The optimum extraction process of flavonoids from mulberry leaves was determined by response surface method.Experimental results showed that the optimum conditions were as follows,ethanol concentration 70.85%vol,extraction temperature 70.13℃,solid-liquid ratio 1: 42.2(g : mL),ultrasonic time 20min.Under these conditions,the predictive flavonoid yield was 4.52%,and the real extraction rate was 4.50%,which was in accord with the predictive value.