Assessing the Gut Microbiota's Ability to Metabolize Oligomeric and Polymeric Flavan‐3‐ols from Aronia and Cranberry

Abstract

Clinical trials investigating the health effects of flavan‐3‐ols yield heterogeneous results due to interindividual variability in the gut microbiota metabolism. In fact, different groups in the population have similar metabolic profiles following (−)‐epicatechin and (+)‐catechin gut microbial metabolism and can be regrouped into so‐called metabotypes. In this study, the capacity of 34 donors to metabolize polymeric B‐type flavan‐3‐ols from aronia and oligomeric A‐type flavan‐3‐ols from cranberry is investigated by in vitro fecal batch fermentations. Less than 1% of the flavan‐3‐ols from both sources are converted into microbial metabolites, such as phenyl‐γ‐valerolactones (PVLs). To further confirm this result, gut microbial metabolites from flavan‐3‐ols are quantified in urine samples collected from participants, before and after a 4‐day supplementation of cranberry extract providing 82.3 mg of flavan‐3‐ols per day. No significant difference is observed in the urinary excretion of flavan‐3‐ols microbial metabolites. Hence, it demonstrates by both in vitro and in vivo approaches that flavan‐3‐ols from aronia and cranberry are poorly degraded by the gut microbiota. The beneficial health impacts of these molecules likely stem from their capacity to affect gut microbiota and their interactions with the gut epithelium, rather than from their breakdown into smaller metabolites.

Supplementation with a cranberry extract favors the establishment of butyrogenic guilds in the human fermentation SHIME system

“…A-ring cleavage [8,43] Lactiplantibacillus plantarum [ASV_69 (100%), ASV_238 (99.77%), ASV_617 (91.86%), ASV_1511 (99.65%), ASV_1979 (91.63%)]…”

“…C-ring cleavage [8,44] Principal bacterial species identified in the gut that are capable of metabolizing flavan-3ols are listed along with the corresponding ASVs and NCBI BLASTN percent identity score. PAC: Proanthocyanidins.…”

“…Increasing evidence suggests a link between the health benefits of PAC and the gut microbiota. Indeed, due to their high degree of polymerization and complex structures, 95% of PAC are not absorbed in the small intestine, are poorly metabolized in the small intestine and reach the colon intact, where they can interact with the microbiota [7][8][9] . Furthermore, recent research has revealed that cranberries are rich in potentially bioactive oligosaccharides.…”

“…Recent studies have emphasized the capacity of (poly)phenols to impact the composition and functionality of the gut microbiota [8,12,13] . Our group has recently proposed that (poly)phenols exhibit a "duplibiotic" action.…”

“…However, this bidirectional interaction has not been fully described, and the way in which PAC/oligosaccharides influence the gut microbiota remains inadequately characterized. We are just at the initial stages of identifying the commensal bacterial species responsible for PAC catabolism and understanding their role in (poly)phenol metabolism [8] .…”