Protecting Skin from UV Exposure with Dietary Polyphenols: Comparison of Phenolic Metabolites in an Ex Vivo Skin Explant Model

Dietary berry consumption generates circulating gut-derived phenolic metabolites linked to systemic health benefits, yet their roles in enhancing skin resilience against environmental stressors are unclear. This study evaluated the protective effects of wild blueberry polyphenolic metabolites on ex vivo human skin biopsies exposed to ultraviolet irradiation. The metabolites were derived from exogenous fermentations (with <i>Lactiplantibacillus plantarum</i> 299 V, <i>L. plantarum</i> Vega, or <i>Bacillus subtilis</i> PXN21), a standardized mixture reflecting metabolites circulating after human gastrointestinal (endogenous) fermentation, or nonfermented berry compounds. Metabolites from the endogenous fermentation treatment provided the most comprehensive protection against UV-irradiation damage, reducing 4-hydroxynonenal protein adducts by 47.4% ± 9.9%, increasing hemeoxygenase-1 expression by 173% ± 26%, and mitigating elastin degradation by 82.8% ± 4.9%. Exogenous fermentation treatments varied in their protective capacities across different markers, reflecting their individualized metabolite profiles and bioactivities. Collectively, these findings demonstrate that blueberry-derived metabolites can enhance skin resilience, highlighting their photoprotective potential.