The Beneficial Effects of Dietary Astragali Radix Are Related to the Regulation of Gut Microbiota and Its Metabolites

Astragali Radix (AR) or its extract has been used as an herbal medicine and dietary supplement in China, Europe, and the United States. The gut microbiota could provide new insights for exploring dietary supplements' underlying mechanism on organisms. However, no reports have focused on the regulatory effect of AR on the gut microbiota as a dietary supplement. In this study, healthy ICR mice of either sex were divided into AR and control (CON) groups and given AR water extract (4.55 mg/kg·day^-1) or saline by gavage for 14 days, respectively. Then 16S rRNA gene sequencing and ultra-high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry-based fecal metabolomics were integrated to investigate the benefits of dietary AR. Weighted gene coexpression network analysis was also introduced to investigate the metabolites with highly synergistic changes. AR supplementation influenced the structure of intestinal microflora, especially enriching short-chain fatty acid-producing bacteria g_Coprobacillus, g_Prevotella, and g_Parabacteroides. AR also significantly altered the fecal metabolome, mainly related to amino acid metabolism, nucleotide metabolism, and bile acid (BA) metabolism. Moreover, the increased secondary BAs and BA-sulfates might closely relate to intestinal microflora. These findings provide valuable insights for future research of dietary AR as a functional food.