乙醇/无机盐双水相体系分离纯化黄芪总黄酮的研究

Separation and purification of total flavonids of Astragalus membranaceus with ethanol/phosphate aqueous two-phase system

目的:研究乙醇/无机盐双水相体系对黄芪黄酮的分离和纯化。方法:以分相能力差异和目标萃取物在其中的分配为考察指标,分析乙醇与几种常用盐的组成双水相体系的及其相图,筛选出乙醇(EtOH)/磷酸氢二钾(K2HPO4)体系为萃取黄芪总黄酮的最佳体系,并研究EtOH/K2HPO4体系中各成分的配比对黄芪黄酮的分配系数和相比的影响。结果与结论:分离纯化黄芪黄酮的最佳条件为:ωEtOH为36.05%,ωK2HPO4为18.20%的EtOH/K2HPO4体系。黄芪黄酮在体系中的分配系数为10.33,萃取率高达96.6%,同时对该体系萃取后上下相中黄芪皂苷和多糖含量进行测定,上相中黄芪皂苷去除率达到92.01%;黄芪多糖全部富集在下相水相,即去除率高达100%。这有利于黄芪粗提取液中总黄酮的分离和纯化。

Objective： To study separation and purification of flavonids with ethanol/phosphate aqueous two-phase system. Method ： The diversity of phase separation ability and the distribution of target products in various systems were taken as indicators to analyze aqueous two-phase extraction systems and phase diagrams formed by ethanol and some common salts, screen out EtOH/ K2 HPO4 system as the optimla system for extracting total flavonids, and study the impact of proportion of components in EtOH/K2HPO4 system on the partition coefficient and phase ratio of flavonids. Result and Conclusion： The EtOH/K2 HPO4 system with ωEOH 36. 05% and ωK2HPO4 18.20% has been proved as the optimal conditions for separating and purifying total flavonoids of Astragalus （TFA）. Under this optimal condition, the partition coefficient and the extraction yield of TFA reached 10. 33 and 96.6% , respective- ly. After extraction, the contents of A. membranaceus saponins and A. membranaceus polysaccharides in top and bottom phases were determined at the same time, showing that A. membranaceus saponins in the removal rate reached 92. 01% , and A. membranaceus pol- ysaccharides were totally concentrated in bottom water phase, indicating a removal rate of 100%. Therefore, this is beneficial to sepa- rate and purify total flavonids from A. membranaceus crude extracts.