Extraction, purification and structural characterization of a novel polysaccharide purified from Lentinula sp. and its antioxidant and hypoglycemic activities

Lentinula sp. as an edible fungus in China, the bioactivity of its polysaccharide has not been exploited. In this study, the polysaccharides from Lentinula sp. were extracted and purified, the structural, antioxidant and hypoglycaemic properties of a novel Lentinula sp. polysaccharide (HMP-1) were characterised. Structural analysis identified HMP-1 as a β-glycosidic-linked heteropolysaccharide (89.15 kDa) made of glucose, galactose, and glucuronic acid, with a porous flake-like structure. HMP-1 showed strong antioxidant activity in DPPH (46.78%), ABTS (90.57%), and ORAC (393.69 μmol TE/mg) assays. It also significantly inhibited α-glucosidase and α-amylase by 76.65 and 81.15%, respectively. In insulin-resistant HepG2 cells, HMP-1 decreased ROS levels by 35.7%, restored SOD and CAT activities, and increased glucose consumption by 58.3. These findings highlight HMP-1 as a promising natural hypoglycaemic agent with dual antioxidant and enzyme inhibitory effects, providing novel insights into structure-activity relationships of natural polysaccharides for diabetes management.