离子色谱−积分脉冲安培法测定肉苁蓉多糖的单糖组成及游离单糖含量

Determination of monosaccharide composition of polysaccharide and free monosaccharides in Cistanches Herba by ion chromatography-integral pulsed amperometry

肉苁蓉多糖和游离态单糖是肉苁蓉中的重要活性成分,具有抗衰老、免疫活性调节等作用。多糖的单糖组成和游离态单糖研究可以为肉苁蓉多糖一级结构、空间结构及肉苁蓉生物活性的研究奠定基础。本研究采用水提醇沉法提取肉苁蓉多糖,多糖水解选取三氟乙酸作为水解酸,建立正交实验考察三氟乙酸浓度、温度、水解时间对多糖裂解的影响,确定最佳水解条件:0.08 mol·L^(-1)三氟乙酸在100℃水解3 h;采用水提法提取肉苁蓉游离态单糖。建立的离子色谱−积分脉冲安培法可在短时间内高效分离11种单糖,方法重复性好,灵敏度高,方法学结果符合定量测定要求,可准确测定肉苁蓉多糖的单糖组成及游离单糖含量。离子色谱法不需要衍生化操作,前处理步骤简单,填补了PMP衍生-HPLC法无法测定果糖的缺陷。肉苁蓉多糖的单糖组成有岩藻糖、阿拉伯糖、鼠李糖、半乳糖、葡萄糖、木糖、甘露糖、果糖、核糖、葡萄糖醛酸,其中葡萄糖、果糖含量相对较高;肉苁蓉水提液中游离态单糖有葡萄糖、果糖、甘露糖。

Polysaccharides and free monosaccharides are important active components in Cistanches Herba,which have functions of anti-aging and immunological activity regulation.The study of monosaccharide composition in polysaccharide and free monosaccharide can lay a foundation for the study of primary structure,spatial structure of Cistanche polysaccharide and biological activity of Cistanches Herba.In this study,a method of water extraction and alcohol precipitation was used to extract Cistanche polysaccharide.Trifluoroacetic acid was selected as the hydrolytic acid for polysaccharide hydrolysis.An orthogonal experimental method is established.Three levels of acid concentration,hydrolysis temperature and hydrolysis time were selected to investigate the optimal hydrolysis condition.The optimal hydrolysis condition was 0.08 mol·L^(-1) trifluoroacetic acid hydrolysis at 100℃for 3 h.The free monosaccharides of Cistanches Herba were extracted by water extraction.The established ion chromatogram integrated pulsed amperometry method can efficiently separate 11 monosaccharides in a short time.The method has good repeatability and high sensitivity,methodological experiment results meet the requirements of quantitative determination.It can accurately determine the monosaccharide composition of Cistanche polysaccharide and free monosaccharide content.Ion chromatography does not require derivatization operation and the pre-treatment steps are simple.This method can measure fructose,but PMP derivation-HPLC method can't.The monosaccharide composition of Cistanche polysaccharide include fucose,arabinose,rhamnosegalactose,glucose,xylose,mannose,fructose,ribose and glucuronic acid,among which the contents of glucose and fructose are relatively high.The free monosaccharides in the water extract of Cistanches Herba include glucose,fructose and mannose.