Dioscorea japonicaThunb. Ethanolic Extract Attenuated Oxazolone-Induced Atopic Dermatitis-like Skin Lesions in BALB/c Mice

− The rhizomes of Dioscorea japonica Thunb. are widely consumed as food and also used to treat diabetes and polyuria in Korea. This study was undertaken to study the anti-atopic dermatitis effects of a 95% ethanolic extract (DJE) of D. japonica in an oxazolone-stimulated murine model of atopic dermatitis (AD). The therapeutic effects of DJE on AD-like skin lesions were assessed on both ears. DJE (1%) or dexamethasone (0.5%; the positive control) were applied to skin lesions for three weeks. Serum levels of IgE and IL-4 were assessed by ELISA (enzyme-linked immunosorbent assay). Histopathological examinations were performed by hematoxylin and eosin (H&E) and toluidine blue staining and revealed DJE significantly reduced dermal thickness and inflammatory cell infiltration when applied to oxazolone-treated ear skin. DJE-treated AD mice also showed lower serum levels of IgE and IL-4 than oxazolone-stimulated controls. Our findings demonstrate DJE might be a useful safe, topical agent for the treatment of atopic diseases.