Therapeutic effects of Euonymus Sachalinensis Extract on Atopic Dermatitis: Evidence from TNF-alpha/IFN-gamma-induced HaCaT Cells and a DNCB- induced Mouse Model

Background Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by immune dysregulation and skin barrier dysfunction. This study investigated the anti-inflammatory and barrier-restorative effects of Euonymus sachalinensis (ES) extract using in vivo and in vitro AD models. Methods A 1-chloro-2,4-dinitrobenzene (DNCB)-induced AD mouse model was used to assess the therapeutic effects of ES through histological analysis, Eczema Area and Severity Index (EASI) scores, and scratching behavior. Western blotting was performed to examine the key inflammatory pathways. In vitro , TNF-α/IFN-γ-stimulated HaCaT cells were treated with ES to evaluate inflammatory mediator suppression and skin barrier restoration. Results ES treatment significantly alleviated AD-like symptoms by reducing epidermal and dermal thickening, mast cell infiltration, and immune organ hypertrophy. The western blot analysis revealed MAPK suppression (ERK, JNK, p38) and NF-κB (IκBα, p65) signaling in dorsal skin tissues. In vitro , ES reduced COX-2 expression, inhibited MAPK phosphorylation, and prevented NF-κB activation and PI3K/AKT pathway signaling. ES also downregulated inflammatory cytokines (IL-13 and IL-4) and chemokines (CCL22 and CCL17), while restoring filaggrin expression and improving skin barrier function. Conclusion The ES extract exerts anti-inflammatory and skin-protective effects by modulating key inflammatory pathways and enhancing epidermal integrity. Identification of bioactive compounds in ES highlights their therapeutic potential. Further studies are required to isolate the active constituents and validate their clinical applicability in AD treatment.