[Structural characterization of Glehniae Radix polysaccharides using partial acid hydrolysis-hydrophilic interaction liquid chromatography-mass spectrometry].

ABSTRACT

Water-soluble polysaccharides from traditional Chinese medicine have properties of complex structure and high molecular, resulting in hardly complete their structural characterization.However, a "bottom-up" approach could solve this problem.Glehniae Radix extract was extracted with hot water and then precipitated by 40% ethanol to obtain Glehniae Radix polysaccharides (RGP). Subsequently, a partial acid hydrolysis method was carried out and the effects of acid concentration, time and temperature on hydrolysis were investigated. Under the optimum hydrolysis condition (1.5 mol•L⁻¹ trifluoroacetic acid, 4 h, and 80 ℃), RGP were hydrolyzed to characteristic oligosaccharide fragments. Futher, a hydrophilic liquid chromatography- mass spectrometry method was used for the separation and structural characterization of the polysaccharide hydrolysates. According to MS and MS/MS analysis of several standard disaccharides, a method for determining the type of polysaccharide glycosidic linkage by mass spectrometry was established. The results showed that the polysaccharide hydrolysates were linear glucan containing 1, 4-glycosidic bonds. And gluco-oligosaccharides with the degrees of polymerization (DP) of 4-11 were obtained after partial acid hydrolysis.