Antiallergic effects of ethanol extract of Cnidium monnieri (L.) Cuss. on DNCB-induced atopic dermatitis in mice

Purpose: To study the anti-allergic effects of ethanol extract of Cnidium monnieri (L.) Cuss. on 2, 4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis in mice.Method: Atopic dermatitis (AD) was induced by DNCB in Balb/c mice, and the mice randomly divided into normal group, negative control group, hydrocortisone group, and ethanol extract of Cnidium monnieri (L.) Cuss. (EECM) group. Ear swelling was determined by measuring the thicknesses of the left and right ears of each mouse. Spleen and thymus indices were calculated from spleen, thymus and body weight values. The levels of TNF-α and IgE in serum were determined by enzyme-linked immunosorbent assay (ELISA). Hematoxylin-eosin (H & E) staining and toluidine blue staining were used to evaluate pathological changes in ear tissue, while high performance liquid chromatography (HPLC) was performed to ascertain the bioactive compounds in EECM.Results: Compared with the negative control group, EECM significantly alleviated skin lesions, reduced thickness of ear swelling, and decreased spleen and thymus indexes of mice (p < 0.05). Moreover, EECM significantly reduced epidermal thickness (p < 0.01). However, EECM did not significantly alter the number of mast cells (p > 0.05). The expressions of TNF-α and IgE in serum were also significantly down-regulated (p < 0.01, p < 0.05). Results from HPLC revealed that the contents of bergapten, imperatorin and osthole in EECM were 0.73, 3.69 and 9.40 mg/g, respectively.Conclusion: EECM ameliorates AD in mice via inhibition of inflammation and by a mechanism that might be related to the regulation of TNF-α and IgE levels. The major bioactive constituents of EECM are osthole, imperatorin and bergapten. Thus, this plant extract has a potential to be developed for the treatment of of atopic dermatitis.