Evaluation of the "Relative Ordered Structure of Hericium erinaceus Polysaccharide" from Different Origins: Based on Similarity and Dissimilarity.

Polysaccharides are organic compounds widely distributed in nature, but structural order and disorder remain a formidable problem. In this study, based on the theoretical framework of the "relative ordered structure of polysaccharide" proposed in our previous work, the structural order of Hericium erinaceus polysaccharides from different regions was evaluated by FT-IR, methylation analysis, and 1 H NMR spectroscopy combined with chemometric methods. The results of principal component analysis and heatmap cluster analysis revealed that 18-subfractions exhibit four different structural types with representative glycoside linkage types: fucogalactoglucan, glucofucogalactan, fucoglucan, and glucan. The main chain of heteroglucans often consists of β-(1 → 6)-Glc p , β-(1 → 4)-Glc p , and β-(1 → 3)-Glc p residues, which are predominantly substituted at the O -3 and O -6 positions. The main chain structure of heterogalactans is α-(1 → 6)-Gal p residues, which may be replaced by Fuc p and Gal p residues at O -2. Overall, our findings demonstrate the validity of the "relative ordered structure of polysaccharide" in Hericium erectus polysaccharides and simplify the complexity of polysaccharide structures.