Dual-action fermented oats (Avena sativa L.): Anti-inflammatory and skin barrier restoration

When the skin is exposed to external stimuli such as ultraviolet radiation, it can lead to dryness and sensitivity, highlighting the importance of skincare. Maintaining skin homeostasis for healthy complexion requires not only controlling the inflammatory response, but also protecting the skin barrier. The study aimed to explore the potential of fermented oats (FO) as an innovative ingredient in skin care products, focusing on its capacity to alleviate inflammation and repair the skin barrier. The present study aimed to characterize the active composition and skin care effects of FO, which underwent enzymatic hydrolysis followed by fermentation with Saccharomyces cerevisiae . To evaluate the anti-inflammatory properties of FO, we performed experiments to inhibit TNF-α/TNFR1 binding, nitric oxide (NO) release in RAW264.7 macrophage cells and neutrophil aggregation in zebrafish embryos. Additionally, the study evaluated the secretion of inflammatory factors, skin barrier function and moisturizing effects using a UVB-irradiated skin model as a surrogate for photodamaged skin. This study reveals that the fermentation process involving Saccharomyces cerevisiae significantly enhances amino acids and their derivatives in FO. Specifically, β -glucan, total protein, and flavonoids in FO increased by 14.78%, 39.13%, and 600%, respectively. FO achieved a 79.87% inhibition rate of TNF-α/TNFR1 binding. It also reduced lipopolysaccharide (LPS)-induced NO release in RAW264.7 cells and inhibited neutrophil recruitment in zebrafish embryos. In a capsaicin (CAP)-stimulated skin model, 3.5% FO suppressed TRPV1 expression. In a UVB-irradiated 3D skin model, FO decreased the secretion of pro-inflammatory cytokines (IL-1α, IL-6, COX2, NF-κB) and significantly upregulated loricrin (128.57%), filaggrin (336.36%), transglutaminase 1 (70.97%), and caspase-14 (217.65%). Additionally, FO enhanced moisturizing efficacy by increasing skin moisture content and AQP3 levels. As a novel fermentation ingredient, FO inhibits the expression of inflammatory factors, improves skin tissue morphology, and enhances hydration, achieving multi-faceted soothing and repairing effects. These findings suggest that Saccharomyces cerevisiae - fermented oat extracts hold promise as an innovative ingredient with anti-inflammatory and skin-protective benefits.