Structural characterization of two novel polysaccharides from Gastrodia elata and their effects on Akkermansia muciniphila

Two homogeneous polysaccharides, GEP-3 and GEP-4, were purified from Gastrodia data, a precious traditional Chinese medicine. Their structural characteristics were obtained using HPGPC, PMP-HPLC, LC/MS, FT-IR, NMR, and SEM methods. GEP-3 was 1,4-glucan with molecular weight of 20 kDa. Interestingly, GEP-4 comprised of a backbone of ->[4)-alpha-Glcp-(1](10)->[4)-alpha-Glcp-(1 ->](5)[6)-beta-Glcp-(1](11)-> 6)-alpha-Glcp-(3 -> and two branches of beta-Glcp and p-hydroxybenzyl alcohol citrate, with repeating p-hydroxybenzyl alcohol attached to the backbone chain at O-6 position of -> 4,6)-alpha-Glcp-(1 -> and O-1 position of -> 3,6)-alpha-Glcp-(1 -> GEP-4 is a novel polysaccharide obtained and characterized for the first time. Bioactivity test indicated that both of them significantly promote the growth of Akkermansia muciniphila (Akk. muciniphila). Furthermore, GEP-3 and GEP-4 promoted the growth of Akk. muciniphila from high-fat diet (HFD) fecal microbiota. These results indicated that GEP-3 and GEP-4 were potential Akk. muciniphila growth promoters.

Automated summary

Two homogeneous polysaccharides, GEP-3 and GEP-4, were extracted from Gastrodia data, a traditional Chinese medicine. GEP-3 was identified as 1,4-glucan while GEP-4 was characterized as a novel polysaccharide. Bioactivity test indicated that both GEP-3 and GEP-4 significantly promoted the growth of Akkermansia muciniphila.