Extraction, Characterization, and In Vitro Hypoglycemic Activity of a Neutral Polysaccharide from the New Medicinal Mushroom Cantharellus yunnanensis (Agaricomycetes).

Polysaccharides serve as promising ingredients for health-beneficial functional foods, while there were no investigations into the structural characterizations and bioactivities of an edible mushroom Cantharellus yunnanensis. In the study, crude polysaccharides from this mushroom were extracted by hot water and isolated by ethanol precipitation. Then, a neutral polysaccharide (named CY-1) was purified from the crude polysaccharide by deproteinization with Sevag reagent, decolorization with a kind of macroporous adsorption resin SP-825, DEAE-52 cellulose column chromatography and dialysis. The physicochemical properties of CY-1 were characterized by UV, IR, SEM, NMR, and HPLC analyses. Structural characterizations revealed that CY-1 is a homogeneous heteropolysaccharide with an average molecular weight of 3.06 × 104 Da. CY-1 exhibited a honeycomb structure with an irregular branching shape, and it was composed of mannose, glucose, fucose, xylose, arabinose, galactose, rhamnose, and glucuronic acid, with molar fractions of 54.83%, 25.11%, 10.28% 4.53%, 2.12%, 1.64%, 0.83%, and 0.64%, respectively. In vitro hypoglycemic tests showed that CY-1 had an inhibitory effect on α-glucosidase. In addition, CY-1 of 160 µg/mL promoted glucose consumption in normal HepG2 cells. These results suggested that CY-1 may be a potential hypoglycemic agent.