Fecal fermentation of human ileal fluid after mango intake impacts on colonic microbiota and microbial (poly)phenol catabolism

Mango (Mangifera indica L.) comprises a rich source of (poly)phenolic compounds, predominantly galloyl-derived (poly)phenols. While a portion of these bioactive compounds are metabolised and absorbed in the upper gastrointestinal tract, the remainder reach the colon, where they are subjected to microbial catabolism. This study investigated the colonic transformation of mango (poly)phenols and their impact on gut microbiota. Ileal fluids (IFs), collected from six ileostomists before and for an 8 h period after mango consumption, were subjected to ex vivo fecal fermentation to simulate colonic conditions. Pre-fermentation (0 h) and post-fermentation (2, 6 and 24 h) samples were analysed by UHPLC-HRMS for changes in (poly)phenol composition, by GC-FID for microbial metabolism (short-chain fatty acids (SCFAs)), and 16S rRNA gene sequencing to assess changes in gut microbiota. A total of 48 phenolics were identified in the fermented IF samples, before and after mango consumption. The main compounds included benzoic acids, hydroxybenzenes and galloyl derivatives, with high interindividual variability. Among the microbial catabolites, 3,4,5-trihydroxybenzoic acid, 3,5-dihydroxy-4-methoxybenzoic acid and 1,3,5-trihydroxybenzene emerged as possible discriminants of fermented mango IFs. The IF matrix, rather than mango (poly)phenols, significantly influenced gut bacterial diversity (p < 0.05, alpha-diversity) and increased microbial SCFAs production (mainly acetic, butyric and propionic acids). A significant positive correlation (p < 0.05) was found between characteristic catabolites in fermented mango IF samples and some commensal and healthy-related bacteria such as Bifidobacterium spp. Overall, despite high interindividual variability, the results suggest that IF-enriched with mango (poly)phenols undergo substantial microbial catabolism and positively impact on the gut microbial environment. The study was registered at clinicaltrials.gov as NCT06182540.