Abstract: This study aims to investigate the effects of five plant polysaccharides from Radix Astragalus, Rhizoma Atractylodis, Radix Scrophulariae, jujubes, Fructus mume on intestinal microorganisms and their metabolites in patients with type 2 diabetes mellitus (T2DM) by using high-throughput sequencing, metabolomic techniques and an in vitro fermentation model. The results showed that plant polysaccharides could significantly improve the structure of the intestinal flora in diabetic patients, and all five polysaccharides could enrich Faecalibacterium and Roseburia and inhibit Escherichia. Plant polysaccharides could regulate the contents of gas medium and short-chain fatty acids, and change the metabolic pathways of amino acids and short-chain fatty acids in the intestinal flora of patients with T2DM. Radix Astragalus, Atractylodis Rhizoma and Radix Scrophularia polysaccharides had significant regulatory effects on the total amount of short-chain fatty acids, and could also regulate the contents of acetic acid, propionic acid, butyric acid, valeric acid, isobutyric acid and isovaleric acid. In addition to these polysaccharides, jujube polysaccharide also increased the content of total gaseous media as well as CO2 and CH4 in patients with T2DM, while Fructus mume polysaccharide could reduce the contents of gas medium and H2S. These results provide a theoretical basis for the screening and utilization of plant polysaccharides and understanding their targeted regulation of intestinal microorganisms.

Key words: plant polysaccharides; type 2 diabetes mellitus; intestinal flora; metabolites