α-D-1,6-glucan from Castanea mollissima Blume alleviates dextran sulfate sodium-induced colitis in vivo.

A homogenous α-D-1,6-glucan (CPA) was extracted from Castanea mollissima Blume. The effect of CPA on ameliorating dextran sulfate sodium induced colitis was investigated. CPA repressed TNF-α and IL-1β level in LPS stimulated RAW264.7 cells. After the intragastric administration of CPA (200 or 400 mg/kg/day), the colon length and body weights of mice with colitis increased and the disease activity index reduced. CPA alleviated colon tissue damage by elevating ZO-1 and occludin protein levels and regulating TNF-α and IL-1β by inhibiting the protein expression of NLPR3 and NF-κB p65. The abundance of Bacteroidetes and Firmicutes was altered and short-chain fatty acid (SCFA) levels, especially propionic, butyric, and isovaleric acids increased significantly. These results indicated that CPA could alleviate colitis by protecting mucosal barriers, reducing inflammation, and regulating intestinal microbiota and SCFA levels. Thus, CPA can be developed as a functional food for the prevention and treatment of colitis.