核桃叶多酚提取及其组成和抗氧化能力探究

Polyphenol of Walnut Leaves(Juglans sigillata)and Exploring Composition and Antioxidant Capacity

基于超声效应提取核桃叶多酚,以多酚得率为评价指标。以不同料液比和处理时间及乙醇体积分数和处理温度、超声功率对核桃叶进行处理,解析核桃叶多酚响应变化,确定多酚较佳提取工艺条件;采用高效液相色谱对核桃叶中多酚类物质种类进行鉴定并定量分析;通过超氧阴离子和羟基自由基的氧化应激来评价核桃叶多酚的抗氧化性。经优化后核桃叶多酚提取的较佳工艺条件为:料液比1∶60、处理时间21 min、乙醇体积分数49%、处理温度61℃、超声功率350 W,在此条件下得到的实际多酚得率(29.32±1.62)mg/g与预测值(27.77 mg/g)的相对误差小;经高效液相色谱从核桃叶中共鉴定出4种单体酚,芦丁和绿原酸含量较高,没食子酸和槲皮素含量较低;核桃叶多酚对超氧阴离子清除率强于羟基自由基,但清除效果低于维生素C,强于BHT。采用多元二次回归方程模型优化出的核桃叶多酚提取工艺条件可行,提取到的核桃叶多酚具有一定的抗氧化能力。

Walnut leaves polyphenol were extracted based on ultrasound effect,and the polyphenol yield was the evaluation index.In this study,walnut leaves were treated with different solid to liquid ratio,treatment time,ethanol concentration,treatment temperature and ultrasound power to analyze the response changes of polyphenol of walnut leaves,and the better extraction process conditions of polyphenol were determined.Secondly,the types of polyphenols of walnut leaves were identified and analyzed by high performance liquid chromatography;the antioxidation of polyphenol was evaluated by the oxidative stress of superoxide anion and hydroxyl radical.The better technic conditions of polyphenol of walnut leaves were obtained as follows:solid to liquid ratio of 1∶60,treatment time of 21 min,ethanol concentration of 49%,treatment temperature of 61℃,and ultrasound power of 350 W.Under these conditions,the relative error of the actual polyphenol yield(29.32±1.62)mg/g and the predicted value(27.77 mg/g)was small;HPLC identified four kinds of monomeric phenol from walnut leaves,the content of chlorogenic acid and rutinum were high in walnut leaves,and the content of gallic acid and quercetin were low;superoxide anion clearance was stronger than hydroxyl radicals,but the clearance effect was lower than vitamin C and stronger than BHT.The multivariable quadratic regression equation model was feasible to optimize the extraction process of the polyphenol of walnut leaves;extracted walnut leaves polyphenol had a certain antioxidant capacity.