Structural elucidation of an active polysaccharide from Radix Puerariae lobatae and its protection against acute alcoholic liver disease.

Radix Pueraria lobata can be used as medicine and food, whose polysaccharide is one of the main bioactive ingredients. To explore the effect and mechanism of Pueraria lobata polysaccharide, a homogeneous and novel water-soluble polysaccharide (PLP1) was successfully isolated and purified from P. lobata by column chromatography in the current study. Structure analysis revealed that PLP1 (Mw = 10.43 kDa) was constituted of the residues including (1 → 4)-α-d-glucose and (1 → 4, 6)-α-d-glucose, which were linked together at a ratio of 5:1 and represented the main glycosidic units. In vitro experiments indicated that PLP1 exhibited a better free radical-scavenging ability than amylose and amylopectin, meanwhile in vivo experiments indicated that PLP1 effectively protected against liver injury in mice with acute ALD through significantly inhibiting oxidative stress to regulate lipid metabolism, increasing short-chain fatty acid production, and maintaining intestinal homeostasis by regulating intestinal flora. Taken together, our results illustrate that PLP1 can regulate intestinal microecology as a feasible therapeutic agent for protecting against ALD on the ground of the gut-liver axis, thus laying a theoretical foundation for the rational exploitation and utilization of P. lobata resources in the clinic.