Cycloartenyl ferulate, a component of rice bran oil-derived γ-oryzanol, attenuates mast cell degranulation

IgE-targeting therapy could provide significant progress in the treatment of allergic inflammation. In this study, we examined the effect of cycloartenyl ferulate (cycloartenol ferulic acid ester; CAF), a natural product from rice bran oil-derived γ-oryzanol, on allergic reaction. When CAF and γ-oryzanol were injected intradermally with anti-DNP IgE into the dorsal skin of rats, the passive cutaneous anaphylaxis reaction induced by DNP-HSA was attenuated. CAF and γ-oryzanol also inhibited the degranulation of DNP-IgE sensitized RBL-2H3 mast cells stimulated with anti-DNP-HSA. IgE conjugated with CAF could not be detected by anti-IgE antibody in the ELISA analysis. Although incubation of IgE with CAF did not decrease the amount of IgE, it was possible to precipitate IgE by centrifugation. These results demonstrate that CAF captures IgE, prevents it from binding to FcεRI, and attenuates mast cell degranulation.