Inhibitory Activity of Citrus Madurensis Ripe Fruits Extract on Antigen-induced Degranulation in RBL-2H3 Cells

Abstract

The purpose of this study was to search edible ripe Citrus fruits which are applicable for functional food materials as juice, tea and/or jam with sweet taste and rich aroma. A fifty percent ethanolic extract (CMR-ext) obtained from the edible ripe fruit of Citrus madurensis exhibited an inhibitory activity of antigen-induced degranulation in anti-dinitrophenyl (DNP) IgE antibody sensitized rat basophilic leukemia (RBL) -2H3 cells. The inhibitory effect of the CMR-ext on degranulation in RBL-2H3 cells was attributable to 3’,5’-di-C-β-glucopyranosylphloretin (1) which is a constituent of C. madurensis. The effect of 1 on Akt and mitogen-activated protein kinases (MAPK) phosphorylation was examined in RBL-2H3 cells. Western blot analysis revealed that 1 (50 μM) inhibited the degranulation by suppression of Akt and p38 phosphorylation.