Hydroxylation-Driven Microbial and Metabolic Reshaping: Coumarin Derivatives as Novel Prebiotics for Aging Gut Health

This study aimed to investigate the therapeutic potential of three naturally occurring coumarin derivatives─coumarin, umbelliferone, and esculetin, which exhibit distinct hydroxylation patterns in mitigating age-related gut dysbiosis through in vitro colonic fermentation models. By integrating antioxidant profiling, short-chain fatty acid (SCFA) profiling, 16S rRNA sequencing, and metabolomics, we assessed their structural specificity in modulating microbial ecology and metabolic pathways. Results demonstrated a hydroxylation-dependent hierarchy in antioxidant capacity and differential regulation of SCFA production. Coumarin partially enriched g__Turicimonas but showed limited SCFA induction, whereas umbelliferone selectively enhanced butyrate synthesis and enriched g__Bacteroides. Esculetin exhibited the broadest impact, characterized by both increased acetate and propionate levels and the concurrent enrichment of g__Ileibacterium and g__Enterococcus. Metabolomic profiling further revealed that three coumarins released antioxidant metabolites, correlating with microbiota-driven detoxification. These findings highlight hydroxylated coumarins as promising prebiotics that counter age-related dysbiosis via multitarget microbiota–metabolite modulation, providing a mechanistic basis for antiaging strategies.