The Gardenia jasminoides extract and its constituent, geniposide, elicit anti-allergic effects on atopic dermatitis by inhibiting histamine in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE Gardenia jasminoides Ellis has been used in traditional medicine for treatment of inflammation, edema, and dermaitis. The aim of this study was to investigate the mechanism by which Gardenia jasminoides extract (GJE) elicits anti-allergic effects in mast cells and in mice with atopic dermatitis (AD). MATERIALS AND METHODS We investigated the effects of GJE and its fractions on compound 48/80-induced histamine release from MC/9 cells and Dermatophagoides farinae-exposed NC/Nga mice. The effects of its constituents on histamine release from MC/9 cells were also investigated. RESULTS GJE and its ethyl acetate fraction (GJE-EA) inhibited compound 48/80-induced histamine release from MC/9 mast cells. The topical application of GJE or GJE-EA to Dermatophagoides farinae-exposed NC/Nga mice reduced the symptoms of AD, inhibited the infiltration of inflammatory cells, and lowered the serum levels of immunoglobulin E and histamine. Both GJE and GJE-EA reduced the expression of cytokines (interleukin [IL]-4, IL-6, and tumor necrosis factor-alpha) and adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) in ear lesions. In addition, the quantitative analysis of GJE and GJE-EA by high-performance liquid chromatography revealed the presence of crocin and geniposide. Geniposide, but not crocin, inhibited the release of histamine from mast cells, which may contribute to the anti-allergic effect of GJE and GJE-EA. CONCLUSIONS These results suggest that GJE and GJE-EA can suppress mast cell degranulation-induced histamine release, and geniposide may be potential therapeutic candidates for AD.