[Effects of ethanol extracts of herbal medicines on dermatitis in an atopic dermatitis mouse model].

Atopic dermatitis is a chronic and relapsing inflammatory skin disease that is characterized by highly pruritic, eczematous skin lesions. Our previous study elucidated that nerve growth factor (NGF) plays an important role in the pathogenesis of skin lesions and inhibition of the physiological effects of NGF can moderate skin lesions in atopic dermatitis. In this study, we investigated the effects of ethanol extracts of herbal medicines on neuritic outgrowth induced by NGF. Four herbal extracts (Geranium thunbergii, Humulus lupulus, Rosmarinus officinalis and Salvia officinalis L.) inhibited NGF-induced neuritic outgrowth in PC12 cells. We also investigated the effects of each herbal extract on dermatitis in NC/Nga, an atopic dermatitis mouse model. The skin lesions of the NC/Nga mice were significantly inhibited by repeated applications of each herbal extract. These results suggested that the four herbal extracts can prevent and moderate the symptoms of atopic dermatitis, and these effects might be appeared by inhibiting the effect of NGF on neuritic outgrowth in lesional skin.