Peucedanum japonicum Thunberg root extract inhibits atopic dermatitis-like skin symptoms

<i>Peucedanum japonicum</i> Thunberg is a perennial herbaceous plant of the genus <i>Peucedanum</i> that belongs to the Apiaceae family and is effective in improving inflammation, gout, and dizziness. However, the skin pruritus improvement effect and mechanism of action of <i>Peucedanum japonicum</i> Thunberg root extract (PJRE) have not yet been reported. We investigated the effects of PJRE on the regulation of pruritus and inflammatory responses in compound 48/80 (C48/80)-treated mice, phorbol 12-myristate 13-acetate (PMA)/A23187-induced human skin mast cells, and LPS-stimulated mouse macrophages. PJRE administration significantly inhibited scratching behavior, skin inflammatory cells, and mast cell infiltration in mice increased by C48/80. PJRE treatment also reduced the PMA/A23187-activated secretion of histamine, inflammatory cytokines, and interleukins via NF-κB activation in HMC-1 cells. PJRE treatment reduced LPS-stimulated secretion of inflammatory cytokines and expression of iNOS and COX-2 through phosphorylation of NF-κB, Akt, ERK1/2, and p38 MAPK in Raw 264.7 cells. PJRE treatment increases HO-1 expression in a concentration-dependent manner via NRF2 nuclear translocation. These results suggest that PJRE has therapeutic potential for alleviating atopic dermatitis-like skin symptoms, which is likely mediated by NF-κB as a transcription factor and Akt, ERK1/2, and p38 MAPK as upstream signaling molecules.