Résumé
Objective To study the chemical structure and the conformation in the aqueous solution for a novel neutral polysaccharide (DMP2-A) purified from Dendrobium moniliforme. Methods The chemical structural characterization was determined with sugar analyses, methylation analyses, and IR spectroscopic methods. Moreover, the molecular weight and conformation in the aqueous solution were analyzed by size-exclusion chromatography (SEC) combined with laser light scattering (LLS). Results The polysaccharide DMP2-A consisted of 1-linked terminal xylosyl residue, 1,3-, 1,4-, and 1,3,6-linked glucosyl residues, 1,3-, 1,4-, and 1,3,6-linked galactosyl residues, 1,3,5-linked arabinosyl residue and 1,3,6-linked mannosyl group. Moreover, the weight-average molecular (Mw) of polysaccharide DMP2-A was determined to be (1.07 × 104). A small amount of aggregates were formed with the aggregation number of approximately 38 in the 0.15 mol/L NaNO3 aqueous solution. Conclusion DMP2-A is a kind of polysaccharide with multi-branch and complicated structure. It’s the first time that the polysaccharide DMP2-A was isolated and the chemical structure and conformation in aqueous solution were reported.