余甘子总多酚的提取及其抗氧化活性研究

Extraction and Antioxidant Activity of Polyphenols from Phyllanthus emblica L.

采用溶剂浸提法提取余甘子多酚,并研究其抗氧化活性。通过福林酚法测定多酚的含量,以提取液中总多酚含量为指标,采用单因素实验确定对多酚提取影响较大的3个因素(浸提时间、浸提温度、乙醇浓度),进一步通过正交试验优化提取方案;通过体外实验,对余甘子多酚在清除DPPH自由基、羟基自由基和抑制自发性肝脂质氧化方面的作用进行研究。结果表明,没食子酸在1~5 mg/m L范围内线性关系良好,线性回归方程为:y=0.1431x+0.0791(r=0.9997);余甘子多酚最佳提取方案为:提取时间135 min,浸提温度70℃,乙醇浓度45%,此条件下的总多酚含量为(0.2427±0.008) mg GAE/mg;余甘子多酚总还原能力在0.2~1 mg/m L范围内稍低于茶多酚,但DPPH自由基清除率、羟自由基清除率、自发性肝脂质氧化抑制率均明显高于茶多酚,其中清除DPPH自由基的EC50为(9±0.01)μg/m L,清除羟自由基的EC50为(0.47±0.01) mg/m L,抑制自发性肝脂质氧化的EC50为(122±2)μg/m L。余甘子多酚具有较好的抗氧化活性,有较好的应用前景。

Polyphenols from Phyllanthus emblica L. were extracted by solvent extraction and their antioxidant activities were studied.The contents of polyphenols was determined by Folin-phenol method,and the extraction rate of polyphenols was taken as the index.Three factor( extraction time,extraction temperature and ethanol concentration) which had great influence on the extraction of polyphenols were determined by single factor experiments. The extraction scheme was further optimized by orthogonal experiment. In vitro experiments were carried out to investigate the scavenging effects of Phyllanthus emblica polyphenols on DPPH free radicals,hydroxyl free radicals,and the inhibition on spontaneous liver lipid oxidation. The results showed that gallic acid had a good linear relationship between 1 and 5 mg/m L,and the linear regression equation was y =0.1431 x + 0.0791( r = 0.9997).The optimum extraction scheme was as follows: Extraction time 135 min,extraction temperature70 ℃,ethanol concentration 45%,the extraction rate of polyphenols was( 0.2427 ± 0.0008) mg GAE/mg. The total reduction capacity of polyphenols in the range of 0.2~1 mg/m L was slightly lower than that of tea polyphenols,but the DPPH free radical scavenging rate,hydroxyl radical scavenging rate and spontaneous liver lipid oxidation were significantly higher than those of tea polyphenols.The EC50 of scavenging nitrogen free radicals was( 9 ± 0.01)μg/m L,the EC50 of scavenging hydroxyl free radicals was( 0.47 ± 0.01) mg/m L,and the EC50 of inhibiting spontaneous liver lipid oxidation was( 122 ± 2)μg/m L.Phyllanthus emblica L.polyphenols would have good antioxidant activity and good application prospects.