Ex Vivo Fecal Fermentation of Human Ileal Fluid Collected After Wild Strawberry Consumption Modulates Human Microbiome Community Structure and Metabolic Output and Protects Against DNA Damage in Colonic Epithelial Cells

Abstract

Scope: Wild strawberries (Fragaria vesca) are richer in (poly)phenols than common commercial strawberry varieties, e.g., Fragaria × ananassa. (Poly)phenols and their microbiota-derived metabolites are hypothesized to exert bioactivity within the human gut mucosa. To address this, the effects of wild strawberries are investigated with respect to their bioactivity and microbiota-modulating capacity using both in vitro and ex vivo approaches. Methods and Results: Ileal fluids collected pre- (0h) and post-consumption (8h) of 225 g wild strawberries by ileostomates (n = 5) and also in vitro digested strawberry varieties (Fragaria vesca and Fragaria × ananassa Duchesne) supernatants are collected. Subsequent fermentation of these supernatants using an in vitro batch culture proximal colon model reveals significant treatment-specific changes in microbiome community structure in terms of alpha but not beta diversity at 24 h. Nutri-kinetic analysis reveals a significant increase in the concentration of gut microbiota catabolites, including 3-(4hydroxyphenyl)propionic acid, 3-(3-hydroxyphenyl)propanoic acid, and benzoic acid. Furthermore, post-berry ileal fermentates (24 h) significantly (p < 0.01) decrease DNA damage (% Tail DNA, COMET assay) in both HT29 cells (∼45%) and CCD 841 CoN cells (∼25%) compared to untreated controls. Conclusions: Post berry consumption fermentates exhibit increased overall levels of (poly)phenolic metabolites, which retains their bioactivity, reducing DNA damage in colonocytes.