Gut Microbiota Modulation by Pomegranate Extract: Insights from a Controlled Supplementation Study

Regular consumption of pomegranate, a polyphenol-rich fruit, is associated with multiple health benefits. As polyphenols reach the colon, they interact with the gut microbiota, influencing both its composition and metabolic activity. This study investigated the impact of a one-week supplementation with two doses of the commercial pomegranate extract Oxylent^® (1.3 and 2.6 g/day) on gut microbiota and metabolite production using the SHIME^® system. Bacterial metabolite production, including short-chain fatty acids (SCFA), urolithins, succinate, and lactate, was assessed using chromatographic and enzymatic assays. The bacterial composition across colonic sections, represented by different fermenters in the SHIME, was investigated using 16 S rRNA amplicon sequencing. Pomegranate extract did not significantly alter SCFA or succinate levels, but reduced L- and D-lactate in the transverse colon; the higher dose (2.6 g/day) also decreased D-lactate in the ascending colon. Microbiota profiling revealed a higher bacterial diversity following pomegranate extract supplementation. However, Prevotella abundance decreased in the ascending and transverse colonic sections, potentially explaining the reduced propionate levels observed in the transverse colon with 2.6 g/day of pomegranate extract. Interestingly, contrasting effects were noted for Mitsuokella genus, which decreased in the descending colon at 1.3 g/day but increased at 2.6 g/day in the transverse and descending colons. Furthermore, the higher dose reduced Enterocloster abundance in the descending colon. Overall, Oxylent^® pomegranate extract influenced both microbial composition and metabolite production, particularly taxa associated with health-related metabolites. These results highlight the potential of pomegranate compounds to beneficially influence the gut microbiota, supporting their role in promoting intestinal health.