Umbelliferone reduces the expression of inflammatory chemokines in HaCaT cells and DNCB/DFE-induced atopic dermatitis symptoms in mice

Umbelliferone (UMB) is a coumarin derivative present in roots and barks of plants, such as Angelica decursiva, Artemisia capillaris, and orange. UMB has been previously reported to exhibit anti-inflammatory, anti-diabetic, and anti-cancer effects. However, the effect of UMB on atopic dermatitis (AD) remains unknown. The purpose of this study was to investigate the anti-atopic effects of UMB on 2,4-dinitrochlorobenzene (DNCB)- and house dust mite extract (Dermatophagoides farinae extract, DFE)-treated mice with AD-like skin lesions and on tumor necrosis factor (TNF)-α/interferon (IFN)-γ-treated HaCaT cells. In DNCB/DFE-treated mice, oral administration of UMB (20 and 40 mg/kg) for 28 days led to a significant decrease in ear thickness, spleen size and weight, serum levels of immunoglobulin E (IgE), IgG1, IgG2a, TNF-α, and interleukin 4 (IL-4), and mast cell infiltration; it also led to the suppression of pro-inflammatory cytokines and chemokines. In addition, UMB reduced the secretion of pro-inflammatory cytokines and chemokines in TNF-α/IFN-γ-treated HaCaT cells via regulation of MAPK, IkB-α/NF-κB, and STAT1 signaling pathways. Taken together, these results indicate that UMB ameliorates AD-associated symptoms and inflammation via regulation of various signaling pathways, suggesting that UMB might be a potential therapeutic agent of AD.