Structural characterization and effect on diabetes mellitus with ulcerative colitis of polysaccharide from Chimonanthus salicifolius

Shiliang tea, derived from the leaves of Chimonanthus salicifolius, has traditionally been used to manage gastrointestinal disorders. This study aimed to isolate and characterize a polysaccharide from Chimonanthus salicifolius (CSP) and evaluate its therapeutic effects in a murine model of diabetes mellitus‑associated colitis.

The structural features of CSP were determined using gel permeation chromatography, gas chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy. Following oral administration of CSP, colonic tissues from diabetic mice were collected for histological examination. Concentrations of short‑chain fatty acids (SCFAs) in colonic contents were measured by gas chromatography.

A polysaccharide (CSP) with an approximate molecular mass of 574.7 kDa was isolated from Chimonanthus salicifolius. Methylation analysis revealed that CSP comprises ten distinct sugar residues, while NMR spectra showed the presence of terminal α-arabinofuranosyl (T-α-Araf), 1,5- and 1,3,5-linked α-Araf, terminal β-galactopyranosyl (T-β-Galp), 1,3,6-, 1,4,6-, 1,4-, and 1,3-substituted β-Galp, as well as 1,4- and 1,3-linked α-glucopyranosyl (α-Glcp) residues in CSP. CSP administration markedly attenuated hyperglycemia and impeded the progression of ulcerative colitis in diabetic mice. CSP significantly suppressed pro inflammatory cytokine production, predominantly via blockade of NF‑κB signaling cascade. CSP reinforced intestinal epithelial barrier function through upregulation of tight junction associated proteins, including claudin 1, occludin, and zonula occludens 1, and concurrently elevated the concentrations of SCFAs within the colonic lumen.

These results indicate that CSP is a bioactive polysaccharide with demonstrable biological activity in animal models, warranting further investigation as a potential therapeutic agent for diabetic colitis.