Antioxidant and immunomodulatory effects of acetylated Morchella esculenta polysaccharide in DSS-induced ulcerative colitis mice.

This study follows the current attempt to discover and develop natural therapeutic substances for counteracting ulcerative colitis. Commercial Morchella esculenta polysaccharide after deproteinization (yielding MP) was hydrolyzed with commercial snailase (yielding EMP) then acetylated (yielding AEMP). MP, EMP and AEMP had different molecular weights (19,583, 5668 and 6352 Da, respectively), although their monosaccharide compositions remained the same. Enzymatic hydrolysis alone did not alter MP's functional groups and bonding. MP and EMP had the same amorphous nature with partially crystalline regions. However, further acetylation after enzymatic hydrolysis introduced new CO of esters and CO stretching of carbonyl groups, while changing significantly the degree of crystallinity and extent of disorder. Compared with MP, both EMP and AEMP had increased in vitro antioxidant activities and showed enhanced antioxidant and immunomodulatory functions in mice through increasing the activities of antioxidant enzymes (SOD, CAT, and GSH-Px) and decreasing the levels of malondialdehyde and inflammatory cytokines (TNF-α, IL-1β, IL-10 and IL-6). Compared with EMP, AEMP led to greater alleviation of dextran sulfate sodium-induced ulcerative colitis in mice. Thus, enzymatic hydrolysis with further acetylation makes MP more potent against ulcerative colitis.