红车轴草不同部位多酚提取工艺优化及抗氧化活性研究

Optimization of extraction process of polyphenols from different parts of Trifolium pretense Linn and its antioxidant activity

目的:优化红车轴草多酚提取工艺,并评价其抗氧化活性。方法:采用超声波辅助提取红车轴草茎、叶和花各部位总多酚,选取多酚含量较高部位作为研究对象,采用响应面法优化红车轴草多酚提取工艺,并通过羟自由基和超氧阴离子自由基的清除效率检测总多酚的抗氧化活性。结果:红车轴草中叶的多酚含量较高,其最佳提取工艺为料液比为1∶79(g/mL),提取时间23 min,乙醇体积分数38%,超声功率800 W,超声温度50℃,此时多酚得率为2.31%,与预测值相近,相对标准偏差为2.16%(n=5)。提取物对羟自由基和超氧阴离子自由基的IC50值分别为0.419,0.428 mg/mL。结论:该提取方法稳定可靠,多酚提取物具有较好的抗氧化活性。

Objective:The present study aimed to optimize the extraction process of polyphenols from Trifolium pratense Linn and evaluate the antioxidant activity in vitro.Methods:Ultrasonic-assisted extraction of total polyphenols from stems,leaves,and flowers was firstly performed,and the parts with higher polyphenol content were selected for further investigation.Then the response surface methodology was used to optimize the extraction process,and its antioxidant activity was evaluated by scavenging rate of hydroxyl radical and superoxide anion radical.Results:The results showed that the content of polyphenols in the leaves is relatively high.The optimal extraction process is as follows:the ratio of solid to liquid is 1∶79(g/mL),the extraction time is 23 min,the volume fraction of ethanol is 38%,the ultrasonic power is 800 W,and the ultrasonic temperature is 50℃;the yield of polyphenols is 2.31%,which is close to the predicted return of 2.26%,and the relative standard deviation is 2.16%(n=5).The IC50 to hydroxyl radical and superoxide anion radical was 0.419 mg/mL and 0.428 mg/mL,respectively.Conclusion:The results indicate that this extraction method is reliable and effective in extracting phenolic compounds from the leaves of Trifolium pretense Linn,and the extracts have good antioxidant activity.