桑白皮总黄酮的超声波协同微波提取工艺及其抗氧化活性研究

Ultrasonic-microwave Synergistic Extraction and Antioxidant Activity of Total Flavonoids from White Mulberry Root-bark

在单因素试验的基础上，采用Box—Behnken设计对桑白皮总黄酮超声波协同微波提取工艺中的乙醇浓度、微波时间和微波功率3因子的最优化组合进行了定量研究，建立并分析了各因子与得率关系的数学模型。同时研究了桑白皮总黄酮对DPPH的清除效果。结果表明：最佳的工艺条件为乙醇体积分数为82％、微波时间153s和微波功率275W。经试验验证，在此条件下，黄酮得率为1．696％，与理论计算值1．688％基本一致。说明回归模型能较好地预测桑白皮中总黄酮的提取得率。当总黄酮质量浓度在13．42-80．51Dg／mL的范围内，其对DPPH自由基的清除率为11．29%-42．06％，且都存在明显的量效关系。

The influences of ethanol concentration, microwave time and microwave power on the yield of total flavonoids from White Mulberry Root-bark with the ultrasonic-microwave synergistic extraction technique were studied according to the Box- Behnken experimental design based on the single factor experiments. One mathematical model established and analyzed by response surface methodology was adequate to describe the relationships between the studied factors and the response of the total flavonoid extraction yield. The scavenging effects of the total flavonoid on DPPH free radical were also studied. Based on the canonical analysis, the optimum extraction conditions were obtained as follows： ethanol concentration 82%, microwave time 153 s and microwave power 275 W. Under the optimized extraction conditions, it can be included that the total flavonoid extraction yield is 1.696%, which is close to the estimated value 1.688% attained by using regression model. This model can be used to predict the experiment results well. When the concentration of the total flavonoids is 13.42-80.51μg/mL, the clearance rate of DPPH free radical is 11.29%-42.06%, and the scavenging activity is correlated with the concentration of the total flavonoids.