The structure elucidation and alleviating effect on liver fibrosis in vivo of a pectin-like polysaccharide isolated from Buddleja officinalis

Buddleja officinalis has been used as a traditional Chinese medicine for years. Although evidence has demonstrated it can enhance liver function, the active material basis remains unknown. We hypothesize polysaccharides from Buddleja officinalis may be the active material against liver disease. Herein, we elucidated the structure of a novel pectin-like polysaccharide designed BOM0.05S2 with a molecular weight of 13.6 kDa. Combined with endo-1, 4-β-Mannanase degradation, we found its backbone consists of alternate 1, 2, 4-linked α-Rhap and 1, 4-linked α-GalpA (RG-I type pectin) and mannoglucan, with branches of 1, 4-, 1, 6- and 1, 3, 6-linked β-Galp, T-, 1, 5- and 1, 3, 5-linked α-Araf, T-linked β-Manp and T-linked α-Glcp substituted at C-4 of 1, 2, 4-linked α-Rhap and C-6 of 1, 4, 6-linked α-Glcp. As speculated, BOM0.05S2 showed a significant improvement on carbon tetrachloride (CCl4)-induced liver damage in mice. Bioactivity test showed that BOM0.05S2 reduced AST, ALT and four indexes of liver fibrosis including LN, HA, IV-C, PC-III. Further, we demonstrated that BOM0.05S2 attenuated the collagenous fiber and α-SMA in liver. These findings highlight the potential of BOM0.05S2 as a lead compound for the treatment of liver fibrosis. •A polysaccharide BOM0.05S2 was isolated and purified from Buddleja officinalis.•BOM0.05S2 was a novel pectin-like polysaccharide.•BOM0.05S2 could alleviate liver fibrosis induced by CCl4 in mice.