Integration of microbial metabolomics and microbiomics uncovers a novel mechanism underlying the antidiabetic property of stachyose

Stachyose is a well-known gut microbiota-oriented prebiotic that could directly reach colon and influence the intestinal microenvironment. Through an in vitro fermentation on fecal microbiota from a drug-naive new-onset and a perennial patient, we for the first time revealed a novel function of stachyose on promoting the microbial transformation from tryptophan to indole catabolites (i.e., indole-3-propionic acid, indole-3-lactic acid and indole-3-carboxaldehyde), which has shown to improve intestinal functions and glucose metabolism. Stachyose increased Bifidobacterium and Lactobacillus genera, while reducing Lactococcus and Streptococcus. Similar regulatory effects on microbial transformation of tryptophan and its related microbiota were confirmed in C57BL/6 mice with high-fat-diet induced impaired fasting glucose and gut dysbacteria. Additionally, stachyose up-regulated microbiota related metabolites with ameliorative effects on type 2 diabetes, i.e., hyocholic acid and conjugated linoleic acid in vitro. Our study proves benefits of stachyose for management of type 2 diabetes via regulating microbial metabolism of tryptophan.