Abstract: Fallen leaves of Salix matsudama Koidz. were used as raw material to extract flavonoids by using 60% ethanol (mass fraction) as solvent, using rutin as reference substance. Optimum conditions of solvent extraction and ultrasonic-assisted extraction were investigated and the extracting effects of two methods were compared. The results show that optimum conditions of solvent extraction are as follows:fallen leaves powder 0.3 g, ethanol mass fraction 60%, ratio of material to liquid 1:35(g:mL), extracting 3 times at 65℃, and 75 min for each time. Yield of flavonoids is 3.83% under the conditions. Optimum conditions of ultrasonic-assisted extraction are: fallen leaves powder 0.3 g, ethanol mass fraction 60%, the ratio of material to liquid 1:35(g:mL), the ultrasonic power 400 W, the ultrasonic wave treatment for twice and 30 min for each time, yield of flavonoids is 4.26% under the conditions.The extracting time of ultrasonic-assisted extraction is 60% shorter than solvent extraction, while yield of flavonoids is 11.23% higher.

Key words: leaves of Salix matsudama Koidz., flavonoids, ultrasonic-assisted extraction