Abstract: The suitable conditions for total flavonoids extraction assisted with ultrasonic wave were investigated with the research objects of Polygonatum cyrtonema cultivated under four common types of forest in North Fujian province,the different contents of total flavonoids were ditermined,and their hydroxyl radical scavenging capacities and combination effects with bovine serum albumin were evaluated respectively.The results showed that the suitable conditions for total flavonoids extraction were:ultrasonic power 250 W,ethanol volume fraction 70%,ultrasonic extraction time 20 min,solid-liquid ratio 1∶20 (g∶mL).Under these optimized conditions,the total flavonoids content of Polygonatum cyrtonema cultivated under moso bamboo forest was the highest which reached (10.30±0.05) mg/g;and the total flavonoids content cultivated under natural broad-leaved forest,Cunninghamia lanceolata forest and managed broad-leaved forest was (5.11±0.06),(5.00±0.03) and (5.00±0.05) mg/g respectively.The hydroxyl radical scavenging rate of the total flavonoids reached 89.38%,and owned obvious fluorescence quenching effect by combination with bovine serum albumin,the exponential equation was y=1647 e^{-0.242 x}(R=0.9969).

Key words: Polygonatum cyrtonema, planting under forest, total flavonoids, hydroxyl radical scavenging, fluorescence quenching capacity