Cynanchum atratum inhibits the development of atopic dermatitis in 2,4-dinitrochlorobenzene-induced mice

Cynanchum atratum Bunge (Apocynaceae) is a folk medicine to treat skin inflammatory diseases. However, the effects of C. atratum on atopic dermatitis have not been elucidated. In this study, we evaluate the effects of aqueous extract of C. atratum (CA) and its molecular mechanism on atopic dermatitis (AD). 1 and 100 mg/mL CA were topically applied to 2,4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions for 11 days. The number of scratching behavior was evaluated for 20 min. AD-like symptoms including elevated serum IgE, skin hyperplasia and mast cell infiltration were investigated. The expressions of pro-inflammatory cytokines and mediators were analyzed in AD-like skin legions. In addition, pro-inflammatory cytokine production was confirmed in human mast cells (HMC)-1 stimulated with PMA plus A23187 (PMACI). Topical application of CA attenuated total serum IgE level and scratching behavior. Skin hyperplasia including epidermis and dermis was ameliorated in CA-treated skin legions. The number of infiltrated mast cells was significantly decreased by CA treatment. In addition, CA reduced pro-inflammatory cytokines, such as IL-6, IL-1β and TNF-α and Th2 cytokine, IL-4, in both of AD-like skin lesions and PMACI-sensitized HMC-1 cells. Furthermore, CA decreased the expressions of NF-κB, phospho-IκBα and MAP kinase. These results suggest the inhibitory effects of CA on the development of AD by regulating pro-inflammatory cytokines and mediators. CA could be an effective substance for the treatment of AD.