响应面法优化超声波辅助提取杜仲叶茯砖茶绿原酸及其体外降血糖抗氧化活性

Optimization of ultrasonic-assisted extraction of eucommia ulmoides leaves Fu brick tea chlorogenic acid via response surface analysis and its hypoglycemic and antioxidant activities in vitro

采用超声波辅助法提取杜仲叶茯砖茶中的绿原酸,利用高效液相色谱法(HPLC)测定绿原酸含量,优化提取工艺,并对其体外降血糖抗氧化活性进行了研究。结果表明,杜仲叶茯砖茶绿原酸最佳提取工艺为:超声功率90 W,乙醇体积分数39%,提取时间50 min,液料比25∶1(m L∶g),提取温度60℃,在该最佳条件下,杜仲叶茯砖茶绿原酸得率为2. 446 1%,与模型预测值基本吻合,表明该提取工艺稳定可行。体外降血糖实验发现,1. 4mg/m L杜仲叶茯砖茶绿原酸对α-胰淀粉酶的抑制率为83. 26%,0. 18 mg/m L杜仲叶茯砖茶绿原酸对α-葡萄糖苷酶的抑制率为96. 80%,体现了较好的降血糖活性。抗氧化结果表明,当杜仲叶茯砖茶绿原酸质量浓度为24μg/m L时,对DPPH自由基的清除率可达97. 94%,相同质量浓度Vc对DPPH自由基的清除率为96. 90%,略低于绿原酸,当杜仲叶茯砖茶绿原酸质量浓度为0. 28 mg/m L时,其还原力为1. 75,显著高于Vc,说明杜仲叶茯砖茶绿原酸抗氧化活性较好。

The eucommia ulmoides leaves Fu brick tea was used to extracted chlorogenic acid by ultrasonic-assisted method,the content of chlorogenic acid was determined by HPLC.On the basis of the single factor experiment,response surface methodology was used to optimize the extraction process,and evaluate the hypoglycemic and antioxidant activity in vitro.The results showed that the optimum condition were as follows:ultrasonic power 90 W,ethanol concentration 39%,extraction time 50 min,ratio of liquid to solid 25∶1(mL∶g),and extraction temperature 60℃,under the best condition,the yield of eucommia ulmoides leaves Fu brick tea chlorogenic acid was 2.446 1%,and which was consistent with the predicted results,it showed that the extraction process is stable and feasible.When the eucommia ulmoides leaves Fu brick tea chlorogenic acid concentration was 1.4 mg/mL,the inhibition rate toα-pancreatic amylase was 83.26%,and when the eucommia ulmoides leaves fu brick tea chlorogenic acid concentration was 0.18 mg/mL,the inhibition rate toα-glucosidase was 96.80%.When the eucommia ulmoides leaves fu brick tea chlorogenic acid concentration was 24μg/mL,the rate of scavenging DPPH radicals was 97.94%,while the same concentration of Vc on the scavenging DPPH radicals was 96.90%,slightly lower than chlorogenic acid.and when the eucommia ulmoides leaves fu brick tea chlorogenic acid concentration was 0.28 mg/mL,the reducing power reached to 1.75,significantly higher than Vc.The results shows eucommia ulmoides leaves fu brick tea chlorogenic acid has good effect on hypoglycemic and antioxidant activity.