金线莲多糖提取工艺优化及其体外抗氧化活性研究

Optimization of extraction process and antioxidant activity in vitro of polysaccharide from Anoectochilus roxburghii

以人工培育金线莲为原料,通过单因素试验考察液固比、提取温度、提取时间、超声波功率、提取次数5个因素对金线莲多糖得率的影响,并在此基础上选取液固比、提取时间及超声波功率3个因素为自变量,金线莲多糖得率为考察指标,采用响应面分析试验设计方法建立回归模型,以优化金线莲多糖提取工艺条件。结果表明,金线莲多糖最优提取工艺条件为:液固比30∶1(mL/g)、提取时间40 min、超声波功率240 W、提取温度60℃、提取次数2次,在此条件下金线莲多糖得率为8.14%,与预测值8.19%的相对偏差为0.61%。体外抗氧化实验结果表明,金线莲多糖对O_(2^(-))·自由基和DPPH自由基的清除作用与浓度呈正相关,其对O_(2^(-))·自由基和DPPH自由基清除率IC50分别为0.744 mg/mL、0.665 mg/mL。金线莲多糖和VC还原力随着质量浓度增加而增大,但VC还原力增加的速度均高于金线莲多糖,表明金线莲多糖具有体外抗氧化活性,但抗氧化能力弱于VC。

The effects of liquid-solid ratio,extraction temperature,extraction time,ultrasonic power and extraction times on the polysaccharides yield of cultivated Anoectochilus roxburghii were investigated by single-factor test.Meanwhile,based on the results of single-factor test,liquid-solid ratio,extraction time and ultrasonic power was chosen as independent variables,and the polysaccharides yield of Anoectochilus roxburghii was selected as response value.Then the regression model was established by response surface analysis experiment design method,so as to optimize extraction process of polysaccharides from Anoectochilus roxburghii.The optimal extraction process were as follows:liquid-solid ratio was 30:1(mL/g),extraction time was 40 minutes,ultrasonic power was 240 W,extraction temperature was 60℃and extraction times was two.Under these conditions,the polysaccharides yield of Anoectochilus roxburghii was 8.14%,which was close to the predicted value(8.19%),with relative deviation of 0.61%.The results of in vitro antioxidant experiment showed that the scavenging activity of polysaccharides on O_(2^(-))·radical and DPPH·radical was positively correlated with the concentration,and the scavenging rates of polysaccharides on O_(2^(-))·radical and DPPH·radical IC50 were 0.744 mg/mL and 0.665 mg/mL,respectively.The reducing power of VC and polysaccharides increased with the increase of mass concentration,but the increasing speed of VC reducing power was higher than that of the polysaccharide from Anoectochilus roxburghii.The results showed that the polysaccharide from Anoectochilus roxburghii had antioxidant activity in vitro,but the antioxidant capacity was weaker than VC.