不同pH值溶剂对昭通乌天麻多糖提取率及抗氧化能力研究

Study on Extraction Rate and Antioxidant Capacity of Zhaotong Gastrodia elata BI.Glauca Polysaccharides with Different pH Solvents

以昭通乌天麻为研究对象,考查不同pH值提取液和不同浓度醇沉液对天麻粗多糖提取率的影响,并对初多糖进行分离纯化,考查其对羟自由基、DPPH自由基(二苯代苦味酰基自由基)的抑制率,评价天麻多糖的抗氧化能力。结果表明,提取液pH值为4时天麻粗多糖提取率最高,为23.6%;当其质量浓度为0.2 mg/m L时对羟基自由基的抑制效果达75.61%,清除效果较好。pH值为4的条件下,85%乙醇醇沉所得多糖对羟基自由基的抑制效果最好,醇沉液体积分数为75%时,多糖对DPPH自由基的抑制率最高。不同pH值条件下提取的天麻粗多糖进行分离纯化后抗氧化能力有一定差异性,pH值为4条件下提取的天麻粗多糖分离纯化后的组分,抗氧化能力优于其他组。酸性条件下,无论是粗多糖还是分离出的多糖组分,其羟基自由基抑制率和DPPH自由基抑制率均高于碱性提取液所提取的多糖组。研究表明,选择合适pH值的提取液更有利于高活性天麻多糖的制备。

Taking Zhaotong Gastrodia elata BI.glauca as the research object,the effects of different pH extracts and different concentrations of alcohol precipitates on the extraction rate of crude polysaccharides from Gastrodia elata BI.glauca were investigated,and the primary polysaccharides were separated and purified,and their inhibition rates on hydroxyl radical and DPPH(diphenyl bitter acyl radical)were investigated to evaluate the antioxidant capacity of Gastrodia elata BI.glauca polysaccharides.The results showed that the extraction rate of crude polysaccharide from Gastrodia elata BI.glauca was the highest at pH 4,which was 23.6%.When its concentration was 0.2 mg/mL,the inhibitory effect on hydroxyl radical reached 75.61%,and the scavenging effect on hydroxyl radical DPPH radical.Under this pH condition,the polysaccharide obtained by 85%ethanol precipitation had the best inhibition effect on hydroxyl radical,and the inhibition rate of polysaccharide on DPPH radical was the highest when the concentration of alcohol precipitation solution was 75%.The antioxidant capacity of crude polysaccharides extracted from Gastrodia elata BI.glauca under different pH conditions after separation and purification had a certain difference.The antioxidant capacity of the separated and purified components of crude polysaccharides extracted from Gastrodia elata BI.glauca under pH 4 was superior to other groups.Under acidic conditions,the inhibition rate of hydroxyl radical and DPPH radical of both crude polysaccharides and separated polysaccharides was higher than that of polysaccharides extracted with alkaline extract.In this study,it was concluded that the extraction solution with proper pH was more conducive to the preparation of high activity gastrodia polysaccharide.