The optimization of ultrasonic-microwave assisted synergistic extraction of Lotus plumule extract rich in flavonoids and its hypoglycemic activity

Lotus(Nelumbo nucifera Gaertn),a kind of perennial aquatic plant,is widely cultivated and consumed by people in Asian countries.Lotus plumule flavonoids(LPF)have been recognized as a hypoglycemic agent.LPF was optimally obtained using novel ultrasonic-microwave assisted synergistic extraction(UMSE)method by response surface methodology(RSM)on the basis of the results of single-factor experiments.Furthermore,the hypoglycemic activity of LPF was investigated by measuring the body weight,fasting blood glucose(FBG)level,and oral glucose tolerance test(OGTT)and analyzing the physiological indexes in streptozotocin-diabetic mice model.The optimum extraction conditions consisted of microwave power 355 W,ultrasonic power 423 W,extraction time 15 min,solid-liquid ratio 1:40,ultrasound/interval time 1/0,and ethanol concentration 70%with the maximum LPF yield of 2.62%.LPF supplementation significantly decreased the body weight,FBG,OGTT,serum total cholesterol(TC),serum total triglycerides(TG),and insulin levels,indicating the antidiabetic activity of LPF.This research verified that the UMSE technique was highly efficient to extract LPF to the maximum extent and the flavonoids from L.plumule exhibited hypoglycemic activity,which showed broad development and application prospects.

Box-Behnken优化超声微波协同萃取柠条花多酚提取工艺及体外抗氧化能力研究

为探究超声微波协同萃取柠条花多酚的影响因素,在单因素试验结果的基础上,采用Box-Behnken设计优化和预测柠条花多酚超声微波协同萃取工艺;同时,对柠条花多酚抗氧化活性进行分析。结果表明,超声微波协同萃取柠条花多酚的最佳工艺条件:乙醇浓度为35%,液料比为31 mL︰g,提取时间为22 min,微波功率为417 W。在此萃取条件下,柠条花多酚的平均得率为4.89%。柠条花多酚清除DPPH、羟基自由基和超氧阴离子自由基活性显著,当柠条花多酚浓度为0.1 mg/mL时,DPPH和超氧阴离子自由基清除率分别为95.1%和94.8%;柠条花多酚浓度为0.2 mg/mL时,羟自由基清除率为94.0%;纯化柠条花多酚清除DPPH,超氧阴离子自由基和羟自由基的IC 50值分别为0.0052 mg/mL,0.0133 mg/mL和0.0209 mg/mL。

超声-微波协同萃取法提取甘草总黄酮工艺研究

采用超声-微波协同萃取工艺提取乌拉尔甘草中的总黄酮，针对液固质量体积比（g／mL）、提取时间、提取温度和乙醇体积分数4个因素对甘草总黄酮提取率的影响进行了正交试验，确定最佳工艺条件为：固（质量）液（体积）比（g／mL）1：30，提取时间10min，提取温度50℃，乙醇浓度80％。在此条件下，甘草总黄酮的提取率为3．25％，比乙醇热回流法的提取率提高了0．32％，比超声辅助法的提取率提高了0．15％，表明超声-微波协同萃取法提取甘草总黄酮具有高效、简单、快速等特点。所获得的粗提物经AB-8大孔树脂和聚酰胺树脂进行纯化后，黄酮类物质的纯度达到96％以上。