Structural characterization and therapeutic potential of exopolysaccharide EPS-W-1 from Lactiplantibacillus plantarum strain ZL1 isolated from kimchi against DSS-induced colitis.

Ulcerative colitis (UC) is associated with intestinal barrier dysfunction, gut microbiome (GM) dysbiosis, inflammation, and immune dysregulation. Lactic acid bacteria-derived exopolysaccharides (LAB-EPS) have biotherapeutic potential to stimulate immune responses and influence the GM. Therefore, this work aimed to extract the bioactive EPS (EPS-W-1) from Lactiplantibacillus plantarum ZL1, isolated from Korean kimchi, and then characterize the chemical structure of EPS-W-1 using HPLC, GC-MS, and NMR. The effect of EPS-W-1 treatment on the UC mice was evaluated. The composition of EPS-W-1 was rhamnose (5.06 %), galactose (25.79 %), glucose (53.37 %), and mannose (10.93 %), and its molecular weight (MW) was 260.34 kDa. The colon length increased in the treatment group H-EPS-W-1 (8.9 cm) compared to the DSS group (4.46 cm). In addition, the H-EPS-W-1 treatment improved histological architecture, regulated the GM, and triggered the higher generation of short-chain fatty acids (SCFAs) than the DSS group. It also modulated immune responses by downregulating IL-6 (-48.64 %) and TNF-α (-60.25 %), while upregulating IL-10 (+107.43 %). Collectively, these findings suggest that EPS-W-1 possesses significant therapeutic potential in ameliorating UC through modulation of the GM and regulation of the immune system.