Modulating effects of chlorogenic acid and arabinoxylan on gut microbiota and Bifidobacterium longum

The gut microbiota, crucial for human health, is significantly modulated by dietary components, such as AX and CA; however, their combined synergistic effects remain poorly understood. Using in vitro fermentation, we examined individual and combined impacts of AX and CA on microbiota composition, metabolic activity, and the functional characteristics of Bifidobacterium longum. AX treatment enhanced short-chain fatty acid production, enriched beneficial genera, suppressed pathogens. In contrast, CA elevated the relative abundance of Megasphaera and upregulated bile acid pathways, while inhibiting Enterococcus. The combined AX-CA treatment amplified these beneficial shifts and enhanced pathogen suppression. Transcriptomic analysis revealed that AX upregulated B. longum genes associated with carbohydrate/amino acid metabolism, whereas CA stimulated lipid metabolism but exhibited dose-dependent growth inhibition. Furthermore, AX promoted the microbial biotransformation of CA to dihydrocaffeic acid. These results demonstrated AX and CA function as complementary prebiotics with significant potential to optimize gut microbial ecology and health-related metabolic functions.