Purification, structural characterization, and anti-ulcerative colitis activity of a novel pectin-like polysaccharide AH-H4-1 from Alhagi honey.

Alhagi honey (AH) has been employed in traditional medicine for treating intestinal diseases, demonstrating significant clinical efficacy. However, it remains unclear which components of AH play a role in the treatment of ulcerative colitis (UC). Here, high molecular weight polysaccharide (AH-H) and low molecular weight oligosaccharide (AH-L) were obtained from AH by dialysis. AH-H showed significant therapeutic activity in dextran sulfate sodium (DSS)-induced UC mouse model. In vitro experiment indicated that the component AH-H4-1 isolated from AH-H was a potential active ingredient. Structure analysis revealed that AH-H4-1 was primarily composed of galacturonic acid, rhamnose, galactose, and arabinose. Its structural backbone consists of 1,4-GalA, 1,2,4-Rha, and 1,2-Rha residues, with branches at the O-4 position of 1,2,4-Rha containing 1,3,6-Gal, 1,6-Gal, and 1,5-Ara. AH-H4-1 demonstrates therapeutic effects by reducing neutrophil accumulation in the intestine and promoting the repair of intestinal barrier function in zebrafish with DSS-induced UC. This study provides a valuable reference for AH in the treatment of UC, and establishes a phytochemical basis for developing AH-derived therapeutics for the treatment of UC.