Isolation, structural characterization, and hypoglycemic ability in vivo of a polysaccharide from Eurotium cristatum mycelium

Fuzhuan brick tea is a distinctive black tea that is produced through post-fermentation. Eurotium cristatum is essential for the development of the flavor of Fuzhuan brick tea and the production of bioactive compounds. This study aimed to isolate and characterize a polysaccharide fraction (ECMP-1) from Eurotium cristatum mycelium and evaluate its hypoglycemic activity in streptozotocin-induced diabetic mice. ECMP-1 is a branched heteropolysaccharide primarily composed of α-mannopyranose and β-galactofuranose, with an average molecular weight of 10.37 kDa. High-dose ECMP-1 (600 mg/kg body weight) significantly reduced fasting blood glucose levels in vivo , with a 66.7% decrease compared to that in diabetic control mice. The oral glucose tolerance markedly improved. ECMP-1 also regulates lipid metabolism by lowering serum total cholesterol, serum triglycerides, and low-density lipoprotein cholesterol while elevating high-density lipoprotein cholesterol. Liver injury induced by diabetes was alleviated as alanine transaminase and aspartate aminotransferase levels decreased significantly after ECMP-1 administration. Moreover, the antioxidant capacity was enhanced, as reflected by increased superoxide dismutase and catalase activities in the liver tissue. Overall, these findings indicate that ECMP-1 exhibits potent hypoglycemic, hypolipidemic, and hepatoprotective activities, suggesting its potential application as a functional food ingredient or natural candidate for antidiabetic drug development. • A Eurotium cristatum mycelium polysaccharide ECMP-1 was obtained. • ECMP-1 is a branched polysaccharide mainly composed of α-mannose and β-galactose. • ECMP-1 reduced fasting blood glucose levels and improved oral glucose tolerance in diabetic mice.