Anti-allergic effects of white rose petal extract and anti-atopic properties of its hexane fraction.

Rosa rugosa is a species of rose native to eastern Asia. The root of R. rugosa has been used to treat diabetes mellitus, pain and chronic inflammatory disease, and a R. rugosa petal extract has a strong anti-oxidant effect. In the present study, we examined if solvent fractions from white rose petal extract (WRPE) had any anti-allergic or anti-atopic effects not previously reported. WRPE and butanol and hexane fractions effectively reduced systemic anaphylactic reactions and anti-dinitrophenyl (DNP) IgE-mediated passive cutaneous anaphylaxis in mice, with the greatest inhibition observed for the hexane fraction. In addition, a significant reduction of scratching behavior by mice after histamine injection suggested this fraction's potential anti-allergic effect. At the cell level, the hexane fraction markedly inhibited beta-hexosaminidase release from RBL-2H3 mast cells and suppressed the expressions of mRNA interferon-gamma and interleukin-4 cytokines produced by T helper cells (type 1 and 2). These results strongly support that the hexane fraction may have an effect on atopic dermatitis, as these 2 cell types play central roles in the pathogenesis of atopic dermatitis. In conclusion, these results suggest that either the hexane fraction or one of its components may be beneficial for the treatment of allergic diseases, including atopic dermatitis.