Effectiveness of Ethanol Extract of Rosa rugosa Thunb. on Ear Edema

This study investigated the anti-inflammatory and skin barrier-restoring effects of a 50% ethanol extract of Rosa rugosa Thunb. (RT50) using both in vitro and in vivo models, including HaCaT keratinocytes and a 1-Chloro-2,4-dinitrobenzene (DNCB)-induced ear edema mouse model. The aim was to evaluate the potential efficacy of RT50 in treating hypersensitivity-related skin conditions, such as atopic and contact dermatitis, and to explore natural therapeutic alternatives with fewer side effects for managing inflammatory skin diseases. Cytotoxicity testing identified non-toxic concentrations of 10, 30, and 60 µg/mL for further analysis. RT50 significantly reduced tumor necrosis factor-α/interferon-γ-induced pro-inflammatory cytokines and chemokines in HaCaT cells, demonstrating its anti-inflammatory properties. In vivo, treatment with RT50 significantly reduced DNCB-induced ear edema, as confirmed by histological analysis. Epidermal and dermal thickness and mast cell infiltration were reduced in a concentration-dependent manner. Serum analysis showed that RT50 decreased elevated levels of Immunoglobulin E/Immunoglobulin G caused by DNCB exposure. The gene expression results further showed that RT50 suppressed DNCB-induced pro-inflammatory cytokines and chemokines in ear tissues. Additionally, RT50 restored skin barrier integrity, which was disrupted by DNCB. Key skin barrier proteins, including filaggrin, involucrin, and loricrin, showed increased expression after RT50 treatment. Factors associated with tight junctions were also positively affected, suggesting that RT50 may play a key role in repairing skin barrier function. These findings highlight RT50 as a promising therapeutic candidate for addressing inflammatory skin conditions by both reducing inflammation and restoring skin barrier integrity.