Hypoglycemic activity in vitro and vivo of a water-soluble polysaccharide from Astragalus membranaceus

The polysaccharide AMP as one main bioactive component of Astragalus membranaceus (Fisch.) Bunge was separated and characterized. The results showed that AMP was a typical acidic heteropolysaccharide dominated by glucose, galacturonic acid and arabinose with typical shear-thinning and fluid-like behavior. Scanning electron microscopy images showed that AMP existed in the state of lamellar aggregates with a smooth compact surface. In addition, AMP exhibited strong antioxidant activity with an oxygen radical absorption capacity value of 278.68 ± 9.31 μM TE per g, and excellent α-glucosidase inhibitory activity and cholate binding ability. Furthermore, in vivo, AMP treatment significantly decreased blood glucose and serum insulin levels, improved glucose intolerance and insulin resistance, regulated the blood lipid profile, alleviated oxidative stress, and relieved liver damage in type 2 diabetes mellitus (T2DM) mice. Pearson correlation analysis suggested that the mitigation of oxidative stress contributed to the hypoglycemic effect of AMP, indicating that it is a beneficial functional food ingredient for T2DM.