茯苓多糖的提取及其分子量测定

Isolation and Molecular Weight Determination of Poria Cocos (Schw.) Wolf

关键词:  茯苓  多糖  提取  分子量

Key words:  Poria cocos (Schw.).Wolf  polysaccharides  extraction  molecular weight

摘要:

目的 优化茯苓多糖的提取工艺，测定茯苓多糖分子量及其分布。方法 采用正交试验设计对影响茯苓多糖提取的因素（超声时间、料液比、提取温度、提取时间）进行优化；以葡萄糖为对照品通过苯酚硫酸法测定茯苓多糖的含量；高效尺寸排阻色谱-多角度激光光散射-示差折光联用（HPSEC-MALLS-RI）测定其分子量及其分布。结果 茯苓多糖的最佳提取工艺为超声时间30 min，液料比1：50，提取温度100℃，提取时间4 h；茯苓多糖含量为93.5%；测得茯苓多糖组分A的重均分子量为4.671×10⁶（±1.003%）Da，分子量分布为12.3%，组分B的重均分子量为6.144×10⁴（±2.466%）Da，分子量分布为87.7%。结论 本方法简便准确，可作为测定多糖分子量分布的方法。

Abstract:

OBJECTIVE To optimize the extraction conditions of polysaccharides from Poria cocos (Schw.).Wolf and to determine the molecular weight (Mw) and its distribution. METHODS Orthogonal test design was employed to optimize the extraction conditions of polysaccharides from Poria cocos (Schw.) Wolf. The ultrasonic time, solid-liquid ratio, extraction temperature and extraction time were respectively taken into account. The total carbohydrate content was determined by the phenol-sulfuric acid method, with glucose as the standard. The Mw and its distribution was determined by HPSEC-MALLS-RI. RESULTS The optimal extract condition of polysaccharide was as follows:the ultrasonic time was 30 min, solid-liquid ratio was 1:50, extraction temperature was 100℃ and extraction time was 4 h. The total carbohydrate content was 93.5%. Polysaccharides Mw of component A and component B from Poria cocos (Schw.) Wolf were determined to be 4.671×10⁶ (±1.003%) Da, 6.144×10⁴(±2.466%) Da, and the Mw distribution of A and B were determined to be 12.3% and 87.7%. CONCLUSION This method is simple and accurate, it can be used to determine the molecular weight and its distribution of polysaccharides.