Effects of Centella asiatica-isolated pectic polysaccharide on dextran sulfate sodium-induced colitis.

Dietary supplementation of polysaccharides demonstrates strong therapeutic actions on inflammatory bowel disease (IBD). Centella asiatica (CA) has traditionally been used in Ayurveda and Chinese medicine. However, the effects of CA-isolated pectic polysaccharides on IBD remain unknown. This study determined the effect of a CA-isolated pectic polysaccharide on IBD. The crude polysaccharide (CA-CP), isolated from a hot-water extract of CA, is a typical pectic polysaccharide composed mainly of galacturonic acid (40.6 %), galactose (27.6 %), arabinose (13.5 %), and rhamnose (8.5 %). CA-CP improved clinical symptoms in a DSS-induced colitis murine model, including weight change (9.9-12.0 %), disease activity index (31.6-51.9 %), colon length (13.2-21.5 %), and spleen weight (21.8-26.3 %). CA-CP effectively regulated the levels of inflammatory and junctional factors by mediating the MAPK and NF-κB pathways. CA-CP partially alleviated DSS-induced crypt destruction, submucosal edema, inflammatory infiltration, and mucin secretion. The content of total short-chain fatty acids increased substantially (cecum 29.8-53.7 %, feces 75.4-109.3 %) with oral CA-CP administration compared to the DSS group. Cecal microbial community analysis revealed that CA-CP administration regulated DSS-induced colitis by reducing the abundance of Escherichia (5.0-10.9 %) and Clostridium (0.3-0.4 %), while increasing the abundance of Bacteroidetes (6.8-8.5 %), Ligilactobacillus (2.7-6.0 %), and Bilophilia (0.3-0.6 %). The findings provide fundamental data for developing novel functional therapeutic agents for the prevention and treatment of colitis, using CA-isolated pectic polysaccharides. Furthermore, to the best of our knowledge, our study is the first to demonstrate the effects of pectic polysaccharides isolated from CA on IBD.