Exploring the Prebiotic Potential of Fermented Astragalus Polysaccharides on Gut Microbiota Regulation In Vitro

Astragalus polysaccharides (APS) are known for their prebiotic properties, and fermentation by probiotics is a promising strategy to enhance the prebiotic activity of polysaccharides. In this study, Lactobacillus rhamnosus was used to ferment APS, and response surface methodology was applied to optimize the fermentation parameters. The optimal conditions were determined as follows: 10.28% APS addition, 5.83% inoculum, 35.6 h of fermentation time, and a temperature of 34.6 °C. Additionally, the effects of Fermented Astragalus polysaccharides (FAPS) on human gut microbiota were investigated through in vitro anaerobic incubation. Fecal samples were obtained from 6 healthy volunteers, which were then individually incubated with FAPS. Results demonstrated that FAPS significantly regulated microbial composition and diversity, increasing the abundance of beneficial gut bacteria such as Lactobacillus, E. faecalis, and Brautobacterium, while inhibiting harmful species such as Shigella, Romboutsia, and Clostridium_sensu_stricto_1. Furthermore, FAPS enhanced the production of short-chain fatty acids (SCFAs), which are increasingly recognized to play a role in intestinal homeostasis. These findings suggested that FAPS offers several advantages in terms of increasing beneficial metabolites and regulating gut microbial composition. This study provides valuable insights for expanding the use of plant-derived polysaccharides in the food industry and for developing functional dietary supplements.