Isolation, Structural Characterization, and Hypoglycemic Activities In Vitro of Polysaccharides from Pleurotus eryngii

Pleurotus eryngii (PE) is an edible mushroom with high nutritional value. Pleurotus eryngii polysaccharides (PEPs) are one of the main active ingredients and manifest a great variety of biological activities. This study mainly focused on the chemical characterization and biological activities of PEPs, which were separated into two fractions (named WPS and P-1). WPS is mainly dominated by beta-glycosidic bonds and contains alpha-glycosidic bonds, and P-1 only contains alpha-glycosidic bonds. The molecular weights of WPS and P-1 were 4.5 x 10(5) Da and 2.2 x 10(4) Da. The result of GC indicated that two the fractions were composed of rhamnose, arabinose, xylose, mannose, glucose, and galactose, with a ratio of 0.35:0.24:0.45:0.24:28.78:1.10 for WPS and 0.95:0.64:0.66:1.84:60.69:0.67 for P-1. The advanced structure studies indicated that the two fractions had no triple-helical structure, where WPS had a dense structure and P-1 had a loose structure. In addition, the antioxidant activity of WPS surpassed P-1, and the two fractions also exhibited a high hypoglycemic activity via inhibiting alpha-glycosidase activities and promoting the expression of PI3K-AKT signaling pathway based on in vitro assay and cell experiments.

Automated summary

This study focused on the chemical characterization and biological activities of Pleurotus eryngii polysaccharides (PEPs). The two fractions, WPS and P-1, exhibited different chemical structures and molecular weights, and showed antioxidant and hypoglycemic activities.