Forsythia suspensa fruit extracts and the constituent matairesinol confer anti-allergic effects in an allergic dermatitis mouse model.

BACKGROUND

Forsythia suspensa is used in traditional medicine to treat inflammation. To clarify the anti-inflammatory and anti-allergic effects of F. suspensa fruits, we determined the therapeutic effects of crude extract, fractions, and a constituent from F. suspensa fruits on a murine atopic dermatitis (AD) model.

METHODS

We investigated the inhibitory effects of F. suspensa extract (FSE), extract fractions, and the constituent matairesinol on histamine release from MC/9 mast cells activated by compound 48/80 and the development of AD-like skin lesions and symptoms in NC/Nga mice exposed to Dermatophagoides farinae (mite) extract. High performance liquid chromatography (HPLC) analysis of FSE and its fractions were evaluated using matairesinol standard.

RESULTS

FSE, FSE methylene chloride fraction (FSE-MC), and FSE water fraction (FSE-water) inhibited compound 48/80-induced histamine release from MC/9 mast cells. Topical application of FSE or FSE-MC to NC/Nga mice exposed to Dermatophagoides farinae suppressed the development of AD-like skin lesions. Quantitative HPLC analysis of FSE and FSE-MC identified the presence of matairesinol. Topical application of matairesinol to NC/Nga mice effectively reduced AD symptoms, inhibited inflammatory cell infiltration, and lowered immunoglobulin E levels in serum. Further study demonstrated that DfE-induced changes in IL-4 and IFN-γ mRNA expression in the ears of NC/Nga mice were reversed by matairesinol application.

CONCLUSIONS

These results indicate that the F. suspensa and its constituent matairesinol might be a therapeutic candidate for treating allergic inflammatory disorders such as AD.