不同提取方法对玄参多糖单糖组分和抗氧化活性的影响

目的研究不同提取方法对玄参多糖的提取率、纯度、单糖组分和体外抗氧化活性的影响,为玄参多糖的提取方法及多糖活性差异提供必要的参考。方法传统水提法、稀碱浸渍法、微波辅助法、酶辅助提取法、超声辅助法被用来提取玄参多糖;采用苯酚硫酸法测定多糖的提取率和纯度;采用高效液相色谱法检测多糖完全水解后单糖的组成;DPPH自由基、羟基自由基、超氧阴离子自由基和总还原力为指标评价玄参多糖的体外抗氧化能力。结果酶辅助提取法获得多糖提取率为7.35±0.43,多糖纯度为54.43%±3.43%,其单糖质量摩尔比例中葡萄糖醛酸和半乳糖酸含量最高,分别为12.1%和8.8%;多糖体外抗氧化活性研究发现,酶辅助法获得多糖清除DPPH自由基能力和超氧阴离子自由基清除能力最高,玄参多糖对羟基自由基的清除不太稳定,其与多糖浓度并不成正相关,还原能力比较发现酶辅助法多糖还原能力最强。结论不同方法提取中酶辅助提取法获得多糖的纯度最高,体外抗氧化活性最强,推测其抗氧化活性和单糖组分比例有关。

Effect of Different Extraction Methods on Monosaccharide Compositions and Antioxidative Activity of Scrophularia Ningpoensis Polysaccharide

Objective Our study was to extract the polysaccharides by the different extraction methods from Scrophularia ningpoensisand further compare their extractive ratio,degree of purity,monosaccharide compositions and antioxidant activity in vitro so as to provide the necessary scientific evidence of explaining the effect of the extraction methods on their degree of purity and antioxidative.Methods Five usual extractive methods including traditional water extraction,dilute alkali immersion,microwave assisted extraction,enzyme assisted extraction and ultrasonic-assisted extraction were employed for gaining the polysaccharides form Scrophularia ningpoensis.The extraction ratio and purity of polysaccharides were determined by phenol sulfuric acid method.The composition of monosaccharide was determined by HPLC following the hydrolysis of polysaccharides.The clearance ability of DPPH free radical,hydroxyl radical,superoxide anion free radical and the reducing power by ferric ion reducing antioxidant power were adopted to evaluate the polysaccharide antioxidative activity above in vitro.Results Extraction ratio and purity of polysaccharides was the highest with a value of 7.35±0.43 and(54.43±3.43)%by enzyme-assisted extraction,respectively.The content of glucuronic acid and galactose as the main monosaccharide were the highest among the polysaccharides by enzyme assistance method with a value of 12.1%and 8.8%,respectively.The scavenging capacity of DPPH free radicals and the superoxide anion radical of polysaccharides obtained by enzyme assistance method were the highest among the polysaccharides above.In addition,The removal of hydroxyl radical was not positively correlated with polysaccharides.Moreover,the reduction capacity of polysaccharides showed that polysaccharides obtained by enzyme assistance method had the highest activity compared with other polysaccharides above.Conclusion The extractive ratio and the purity of polysaccharides extracted by enzyme-assisted extraction method were proved to be the highest.In addition,their antioxidant activity showed that polysaccharides formedby enzyme-assisted extraction method was the strongest,implying that the antioxidant activity is related to the monosaccharide compositions of polysaccharides.