A novel pectic polysaccharide from Prunella vulgaris L. and its therapeutic potential in alleviating alcoholic liver injury by regulating lipid metabolism and inflammation.

Prunella vulgaris L. (XiakuCao) is a traditional edible Chinese medicinal herb widely used for its purging properties. While its polysaccharides are known for diverse bioactivities, their potential in treating liver diseases remains closely linked to their specific structural features. Most reported polysaccharides from Prunella vulgaris L. have been complex heteropolysaccharides isolated by hot water. In this study, a new homogeneous polysaccharide, designated AO3-1, was isolated for the first time from Prunella vulgaris L. by ammonium oxalate solution after water treatment. Structural analysis revealed that AO3-1 is mainly composed of α-D-1, 4-GalpA, consistent with a typical pectic polysaccharide. Pharmacological evaluations demonstrated that AO3-1 has significant therapeutic effects in alleviating alcoholic liver injury (ALD), as indicated by the reduction of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and the mitigation of hepatic steatosis (TG, TC, LDL-C and HDL-C). Notably, AO3-1 treatment suppressed systemic inflammation (IL-6, IL-1β and TNF-α) and effectively modulated intestinal microecology, suggesting a protective role mediated by the gut-liver axis. These findings provide the first evidence of a unique pectic polysaccharide from Prunella vulgaris L. with potent anti-ALD activity. Our study highlights the potential of AO3-1 as a novel functional food ingredient or therapeutic agent for managing alcoholic liver injury, offering a new strategy for the valorization of herbal processing by-products.