Isolation, purification, and structural elucidation of polysaccharides from Alhagi-honey

The polysaccharide extract (PE) of Uyghur medicinal preparation Alhagi-honey was prepared by water extraction and alcohol precipitation method. The purified polysaccharide AP1-1 was obtained from PE by macroporous adsorption resin chromatography, DEAE cellulose chromatography, and Sephadex gel chromatography; the homogeneity and the molecular weight of AP1-1 were determined by gel filtration; and the acid hydrolysis, periodate oxidation, Smith degradation, and NMR analysis were used to analyze the chemical structure of AP1-1. The result showed that AP1-1 was a homogeneous polysaccharide, whose relative molecular weight was 9.97x10(4). Through high-performance capillary electrophoresis analysis, we found that its molecular structure was composed of mannose, glucose, galactose, and galacturonic acid with a molar ratio of about 1.1:1.9:3.9:2.1. The main chain of AP1-1 was mainly made up of 4)-d-GalpA-(14)-d-GalpA-(14)--d-Galp-(14)--d-Galp-(16)-d-Glcp-(14)-d-Glcp(1, while the side chain is composed of 6)--d-Glcp and 2-CH3--d-Man.