中文摘要：

黄酮类化合物是乌腺金丝桃植物的主要生物活性成分之一．为了研究开发乌腺金丝桃的应用价值，本文以乌腺金丝桃为材料，通过单因素和响应面法得到乌腺金丝桃中总黄酮提取的最佳工艺条件为超声功率500,W、超声温度60℃、乙醇体积分数62%,、液料比37﹕1、提取时间32,min，该条件下乌腺金丝桃中总黄酮提取得率为6.20%,．在10～500,μg/mL范围内，乌腺金丝桃黄酮提取液对不同自由基表现出不同的清除能力，其对DPPH自由基的清除能力相对最强(IC50值为322.58,μg/mL)，而对ABTS自由基的清除能力最弱．

英文摘要：

Flavonoid is one of major bioactive components in Hypericum attenuatum Choisy.In this study,the conditionsfor ultrasonic extraction of total flavonoids from Hypericum attenuatum Choisy were optimized with the methods of singlefactor and response surface to explore the application value of Hypericum attenuatum Choisy.The results showed that theoptimal conditions for the extraction of total flavonoids from Hypericum attenuatum Choisy were500,W ultrasonic power,60℃temperature,62%,ethanol concentration,37﹕1,liquid-solid ratio and32,min extraction time.Under these conditions,the yield of total flavonoids from Hypericum attenuatum Choisy was6.20%,.Its extract exhibited different scavenging capacitieson different radicals,and it has better scavenging capacities on DPPH radical with an IC50,value of322.58,μg/mLand poor scavenging capacities on ABTS radical with the concentration of10-500,μg/mL.