Structural elucidation of a pectic polysaccharide from Fructus Mori and its bioactivity on intestinal bacteria strains

Many studies suggested that polysaccharides could impact on the gut microbiota. To discover new polysaccharides which influence intestinal beneficial bacteria, a pectin polysaccharide FMP-6-S2 with an average molecular weight of 86.83 kDa was purified from Fructus Mori. The monosaccharide residue analysis indicated that FMP-6-S2 was composed of rhamnose, galacturonic acid, galactose and arabinose in a molar ratio of 30.86: 24.78: 28.70: 15.61. The backbone of FMP-6-S2 contained 1, 4-linked alpha-GalpA and 1, 2-linked alpha-Rhap with branches substituted at C-4 position of rhamnose. The branches were composed of 1, 4-linked beta-Galp, terminal (T) - and 1, 3, 6-linked beta-Galp, T-and 1, 5-linked alpha-Araf. Bioactivity test results suggested that FMP-6-S2 and its degraded product could promote growth of intestinal bacteria, B. thetaiotaomicron, which is a dominate strain in the gut of human to benefit intestinal mucosa. These results suggested that FMP-6-S2 and its degraded product might improve human wellness by modulating B. thetaiotaomicron.