Poncirus Trifoliata (L.) Raf. Extract Inhibits the Development of Atopic Dermatitis-like Lesions in Human Keratinocytes and NC/Nga mice

This study investigated the anti-allergic effect of Poncirus trifoliata (L.) Raf. (PT) on human keratinocytic HaCaT cells in vitro and on 2,4‐dinitrochlorobenzene (DNCB)-induced atopic dermatitis-like lesions in vivo. The release of TARC, MCP-1, IL-6 and IL‐8 is increased by IFN-γ and TNF-α in HaCaT cells, and PT extract suppressed the increased production of TARC, MCP-1, IL-6, and IL‐8. PT extract recovered the expression of filaggrin decreased by IFN-γ and TNF-α. in vivo experiment, PT administration decreased the skin severity score, thickening of the epidermis, movement of inflammatory cells into the dermis, and serum IgE level as compared to DNCB treatment. Moreover, the decrease of filaggrin and loricrin induced by DNCB treatment was recovered by PT administration. The levels of IL-4, IL-5, IL-13 and eotaxin in mouse splenocytes increased after treatment with concanavalin A, and the secretions of IL-4, IL-5, IL-13 and eotaxin were lower in the PT-treated group than in the DNCB group. These findings may indicate that PT is useful in drug development for the treatment of AD.