Anthocyanidin inhibits immunoglobulin E-mediated allergic response in mast cells

This study is to investigate the anti-allergic effect of anthocyanidin and to explore its possible mechanism.  The experiments of passive cutaneous anaphylaxis reaction (PCA) and colorimetry were used to determine the effect of anthocyanidin on degranulation of mast cells in vivo.  For in vitro study, various concentrations of anthocyanidin (100, 50 and 25 µmol·L⁻¹) were added to the culture medium of mast cells cultured with 100 µg·L⁻¹ of dinitrophenyl (DNP) specific IgE overnight.  The azelastine (100 µmol·L⁻¹) was selected as the positive contro1.  The antigen (DNP-human serum albumin, DNP-HAS)-induced release of degranulation was measured by enzymatic assay, histamine was determined by EIA, and interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured by Western blotting, separately.  In addition, the effects of anthocyanidin on phosphorylation of NF-κB, p38MAPK and Akt were observed by Western blotting.  The results showed that treatments with anthocyanidin (100 and 50 mg·kg⁻¹) were followed by a decrease in PCA of rats.  Anthocyanidin (100 and 50 µmol·L⁻¹) obviously suppressed the degranulation from mast cells, whereas results from anthocyanidin (100 and 50 µmol·L⁻¹) group indicated significant inhibitory effect on histamine,  the calcium uptake, TNF-α, IL-6, phosphorylation of NF-κB, p38MAPK and Akt of mast cells induced by antigen.  Anthocyanidin may suppress the anaphylactic reaction by inhibiting the action of mast cells.  NF-κB, p38MAPK and Akt at least in part contribute to this event.