Metagenomic insights into urolithin formation from rambutan rind extract by rat faecal-derived microbiome

reflecting shared metabolic frameworks rather than conserved urolithin biosynthetic pathways, with highly divergent homologues (Eadh1, Eadh2, Eadh3, and Ucdh). Together, these findings demonstrate that rambutan rind extract can support urolithin formation in rat faecal-derived microbial consortia and highlight functional associations consistent with alternative or yet-uncharacterised microbial strategies for ellagitannin biotransformation. These findings support a discovery-driven framework for investigating urolithin biotransformation in non-human gut microbiomes using ellagitannin-rich agricultural substrates. KEY POINTS: • Rambutan rind extract supports urolithin formation in rat-derived gut microbiota. • Substrate concentration influences urolithin production under ex vivo conditions. • Rat gut microbiota shows homologues' divergence in urolithin-associated proteins.