牛蒡叶多酚的超声波辅助提取及抗氧化活性、成分分析研究

Studies on ultrasound-assisted extraction,antioxidant activity and composition of phenolics from burdock leaves

利用超声波辅助法提取多酚,并研究了提取物的抗氧化活性和多酚成分。结果表明,超声波功率、提取时间的增大对多酚提取具有明显促进作用。通过实验得出了超声波辅助法提取多酚的最佳条件为:提取时间30min,超声波功率200W,提取温度30℃,液料比20∶1mL/g。在此条件下,通过实验验证得出,多酚提取率平均值为8.810mg/g。DPPH自由基实验、羟自由基清除能力实验结果表明,牛蒡叶提取物具有较强的抗氧化活性,牛蒡叶提取物浓度为1.00mg/mL时,提取物对DPPH自由基的清除率为51.56%。牛蒡叶多酚的主要成分为绿原酸、咖啡酸、对香豆酸、芦丁等。牛蒡叶提取物的强抗氧化活性主要是这些多酚化合物共同作用的结果。

Ultrasonic technique was employed to extract phenolics from burdock leaves. The effects of four independent variables（ time,ultrasonic power,temperature and solvent to solid ratio） on the recovery of phenolics from burdock leaves were evaluated.The optimal conditions for ultrasonic extraction of phenolics were determined. The optimal conditions to obtain the highest recovery of phenolics were： 30min of extracting time,200W of ultrasonic power,30℃ of extraction temperature and 20∶1mL/g of solvent to solid ratio.Under these optimal conditions,the recovery of phenolics was 8.810mg /g. The experiments indicated that the antioxidant activity （ DPPH radical scavenging ability,hydroxyl radical scavenging capability） of the extracts from burdock leaves was very high.It was found that the extract of burdock leaves containd chlorogenic acid,o-hydrobenzoic acid,caffeic acid,rutin, p-coumaric acid,etc. The high antioxidant activity is probably due to the combined action of these phenolic compounds present in the extract.