A pectic polysaccharide isolated from Achyranthes bidentata is metabolized by human gut Bacteroides spp

Int J Biol Macromol. 2023 Sep 1:248:125785. doi: 10.1016/j.ijbiomac.2023.125785. Epub 2023 Jul 13.

Abstract

Achyranthes bidentata (A. bidentata) is a famous traditional Chinese medicine (TGM) for treatment osteoporosis. Polysaccharides, a major factor for shaping the gut microbiota, are the primary ingredients of A. bidentata. However, bioactivity of A. bidentata polysaccharide on human gut microbiota (HGM) remains unknown. Here, a homogeneous pectic polysaccharide A23-1 with average molecular weight of 93.085 kDa was extracted and purified from A. bidentata. And A23-1 was compsed of rhamnose, glucuronic acid, galacturonic acid, glucose, galactose and arabinose in a molar ratio of 7.26: 0.76: 5.12: 2.54: 23.51: 60.81. GC-MS, partial acid hydrolysis and NMR results indicated the backbone of A23-1 was composed of 1, 2, 4-Rhap and 1, 4-GlapA, while the branches were composed of galactose, arabinose, glucose and glucuronic acid. Further, A23-1 was found to be degraded into monosaccharides and fragments. Taking Bacteroides thetaiotaomicron (BT) as a model, we suggested three polysaccharide utilization loci (PULs) might be involved in the A23-1 degradation. Degraded products generated by BO might not support the growth of probiotics. Besides, acetate and propionate as the main end products were generated by Bacteroides spp. and probiotics utilizing A23-1. These findings suggested A23-1 was possible one of food sources of human gut Bacteroides spp.

Keywords: Achyranthes bidentata; Gut microbiota; PULs; Polysaccharides; SCFAs.

MeSH terms

  • Achyranthes* / chemistry
  • Arabinose / metabolism
  • Bacteroides thetaiotaomicron* / metabolism
  • Galactose
  • Glucose
  • Glucuronic Acid
  • Humans
  • Pectins
  • Polysaccharides / chemistry

Substances

  • Pectins
  • Galactose
  • Arabinose
  • Polysaccharides
  • Glucose
  • Glucuronic Acid