Inhibitory effect of lappaol A on IgE/antigen-mediated allergic responses in in vitro and in vivo models

The biological effect of lappaol A, a lignan, is derived from Arctium lappa, and is relatively unknown; however, lignans have various beneficial properties. Therefore, we investigated the effects of lappaol A on the immunoglobulin E/antigen (IgE/Ag)-mediated allergic response in mast cells and mice. Lappaol A significantly reduced the release of β-hexosaminidase, IL-4, TNF-α, PGD2 and LTC4 with IC50 values of 131.3 μM, 11.58 μM, 59.50 μM, 17.85 μM and 10.99 μM, respectively, in IgE/Ag-activated RBL-2H3 cells. Moreover, lappaol A suppressed the activation of the arachidonate and FceRI signaling cascades in the cells. Furthermore, lappaol A suppressed the IgE/Ag-mediated passive cutaneous anaphylaxis reaction, ear edema and mast cell infiltration in the ear tissues of IgE/Ag-exposed mice. In conclusion, these findings suggest that lappaol A exhibits anti-allergic activity by inhibiting the activation of the arachidonate and FceRI signaling cascades in IgE/Ag-activated mast cells. Therefore, this information may help to elucidate the anti-allergic action of lappaol A and Arctium lappa L.