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

This study investigates the potential of fermented oats (FO)—prepared through enzymatic hydrolysis followed by Saccharomyces cerevisiae fermentation—as a multifunctional skincare ingredient capable of addressing inflammation and skin barrier impairment caused by environmental stressors such as UVB radiation. The authors begin by highlighting the biological challenges associated with UV-induced skin damage, including excessive reactive oxygen species (ROS) production, inflammatory cytokine activation, TRPV1 sensitization, and degradation of barrier proteins such as loricrin, filaggrin, and transglutaminase 1. These processes collectively lead to dryness, irritation, and impaired barrier function, which are central concerns in sensitive skin care.

To address these challenges, the study characterizes the biochemical transformation of oats during yeast fermentation. The process substantially elevates critical bioactive compounds: β-glucan increases by 14.78%, total protein by 39.13%, and flavonoids by 600%. Fermentation also enriches amino acids and derivatives while avoiding solvent-related safety concerns inherent to traditional extraction methods. This biochemical enhancement lays the foundation for the material's improved bioactivity.

The anti-inflammatory effects of FO were evaluated using three complementary models. First, FO exhibited a strong 79.87% inhibition of TNF-α binding to its receptor TNFR1, demonstrating its capacity to prevent cytokine-mediated inflammation. Second, in RAW264.7 macrophages, FO significantly reduced LPS-induced nitric oxide release, indicating inhibition of inflammatory signaling pathways. Third, in zebrafish embryos, FO suppressed neutrophil recruitment, further supporting its in vivo anti-inflammatory potential. Additionally, in a capsaicin-stimulated model, FO at 3.5% concentration downregulated TRPV1 expression, suggesting its potential to alleviate stinging, itching, and burning sensations associated with skin sensitivity.

To evaluate FO’s effects on skin barrier repair, the authors employed UVB-irradiated 3D reconstructed skin models. FO markedly reduced pro-inflammatory cytokines including IL-1α, IL-6, COX2, and NF-κB. Simultaneously, it significantly enhanced key barrier-related proteins: loricrin (128.57%), filaggrin (336.36%), transglutaminase 1 (70.97%), and caspase-14 (217.65%). These improvements indicate strengthened epidermal structure, accelerated barrier recovery, and enhanced natural moisturizing factor formation. Additionally, FO improved hydration by boosting aquaporin-3 (AQP3) levels and skin moisture content.

Collectively, these results demonstrate that FO provides multi-dimensional benefits, integrating anti-inflammatory activity, TRPV1-mediated soothing effects, barrier protein restoration, and improved hydration. The study concludes that Saccharomyces cerevisiae–fermented oat extract is a promising, safe, and highly effective ingredient suitable for formulations targeting sensitive, dry, or photodamaged skin.