龙脑樟去油枝叶中总多酚的酶解-超声辅助提取及抗氧化活性

Enzymolysis-ultrasonic-assisted Extraction and Antioxidant Activity of Total Polyphenols from Degreasing Cinnamomum caraphora Leaves

为探讨龙脑樟去油枝叶中总多酚的酶解-超声辅助提取工艺,在单因素实验的基础上,通过Box-Behnken设计-响应面法研究纤维素酶用量(X_1)、乙醇浓度(X_2)、液料比(X_3)对龙脑樟去油枝叶中总多酚提取率的影响;同时,以清除DPPH自由基和羟基自由基的能力为评价指标,对总多酚提取物的抗氧化活性进行测定。结果表明,各因素对总多酚提取率的影响顺序为液料比(X_3)>乙醇浓度(X_2)>酶用量(X_1);酶解-超声辅助提取龙脑樟去油枝叶中总多酚的最优工艺条件为:酶用量1.9%,乙醇浓度54%,液料比34 m L/g,酶解温度50℃,酶解时间1.5 h,超声时间30 min,超声频率45 k Hz,超声功率360 W,超声温度70℃;在此条件下,总多酚提取率的平均值为22.08 mg/g,与预测值相近,二次回归模型预测性良好。总多酚提取物对DPPH自由基和羟基自由基的清除作用均呈现量效关系,半数抑制浓度(IC_(50))值分别为0.36和0.15 mg/m L,表明总多酚提取物具有较强的抗氧化能力。

In order to investigate enzymolysis-ultrasonic-assisted extraction of total polyphenols from degreasing Cinnamomum caraphora（ L.） Presl leaves,Box-Behnken design coupled with response surface analysis based on the single factor experiments was adopted to study the effects of influencing factors including cellulase dosage（ X1）,ethanol concentration（ X2） and liquid-solid ratio（ X3） on the extraction rate of total polyphenols. Antioxidant activity of extract of total polyphenols was estimated by testing DPPH radical and hydroxyl radical scavenging ability. The results showed that the effects of above factors on the extraction rate of total polyphenols from degreasing C. caraphora leaves were in the following order： liquid-solid ratio（ X3） 〉 ethanol concentration（ X2） 〉 cellulase dosage（ X1）,and the optimal extraction conditions were as follows： 1% as cellulase dosage,55% ethanol solution as extraction solution,30 m L/g as ratio of liquid to solid,50 ℃ as enzymolysis temperature,1. 5 h as enzymolysis time,30 min as ultrasonic time,45 k Hz as ultrasonic frequency,360 W as ultrasonic power,70 ℃ as ultrasonic temperature. Under the optimal conditions,the mean valueof extraction rate of total polyphenols reached 22. 08 mg/g,which was close to the predicted response value. Therefore,the quadratic regression model can be used to predict the enzymolysis-ultrasonic-assisted extraction conditions of total polyphenols from degreasing C. caraphora leaves. Extract of total polyphenols exhibited a dose-dependent scavenging activity against DPPH radical and hydroxyl radical. Its half maximal inhibitory concentration（ IC50） were 0. 36 and 0. 15 mg/m L,respectively,which suggested extract of total polyphenols had high antioxidant activity.