Prebiotic Activity of Acorus gramineus Rhizome Extract and Its Effects on Obesity and Gut Inflammation.

Acorus gramineus (sweet flag), a medicinal plant, especially its rhizome, shows strong antioxidant and anti-inflammatory effects; however, its efficacy in treating intestinal inflammation and obesity is still unexplored. In this study, we investigated the prebiotic activity of sweet flag rhizome extract (SRE) and its preventive effects against high-fat diet (HFD)-induced obesity and colonic inflammation. The prebiotic activity was assessed based on the prebiotic activity scores of four probiotic strains. SRE was administered to mice fed an HFD for 8 weeks, and obesity- and inflammation-related biomarkers were analyzed. The results showed that SRE was utilized as effectively as inulin by the probiotic strains, suggesting that SRE has the potential to influence the gut. Additionally, the administration of 100 mg/kg SRE mitigated colonic inflammation by restraining gut permeability, endotoxemia, and colonic shortening, and improved gut barrier function by restoring zonula occludens-1 protein expression. SRE ameliorated obesity-related symptoms by suppressing weight gain, glucose intolerance, serum lipid biomarkers, and liver damage. Altogether, this study highlights the protective effects of SRE against obesity and intestinal inflammation and provides data for the further application of SRE as a prebiotic.