Suppressive effect of mangosteen rind extract on the spontaneous development of atopic dermatitis in NC/Tnd mice

Atopic dermatitis (AD) is a chronic and relapsing skin disorder characterized by pruritic and dry skin lesions with allergic inflammation. Recent studies have revealed anti‐inflammatory and anti‐allergic effects of xanthones in mangosteen through regulation of the nuclear factor (NF)‐κB signaling pathway. Activation of NF‐κB signals is responsible for allergic inflammation in AD. To develop a new preventive therapy for AD, we examined the effects of the natural medicine, mangosteen rind extract (ME), on AD in a murine model. ME (250 mg/kg per day) was administrated to NC/Tnd mice, a model for human AD, for 6 weeks to evaluate its preventive effects on AD. We also confirmed the effects of ME on various immune cell functions. Oral administration of ME prevented the increase of clinical skin severity scores, plasma total immunoglobulin E levels, scratching behavior, transepidermal water loss and epidermal hyperplasia in NC/Tnd mice; moreover, no adverse effects were noted. We demonstrated that ME suppressed thymic stromal lymphopoietin and interferon‐γ mRNA expression both in vitro and in vivo. Not only immunoglobulin E production from splenic B cells but also immunoglobulin E‐mediated degranulation of bone marrow‐derived cultured mast cells was significantly reduced by the addition of ME to the culture. In addition, mRNA expression levels of nerve growth factor were decreased in ME‐administrated NC/Tnd mice compared with those of controls. Keratinocyte proliferation was well‐controlled by ME application. Oral administration of ME exhibited its suppressive potential on the early development of AD by controlling inflammation, itch and epidermal barrier function.