Inhibition of antigen-induced degranulation by aryl compounds isolated from the bark of Betula platyphylla in RBL-2H3 cells.

The methanolic extract of the bark of Betula platyphylla was found to suppress antigen mediated degranulation of RBL-2H3 cells. Four arylbutanoids (1-4) and eight diarylhepatonoids (5-12) were isolated from the methanolic extract using bioassay-guided fractionation. Among them, compounds 4 and 12 were isolated and assigned for the first time. Compounds 1, 2, 3, 5, 10, and 12 showed remarkable inhibitory activity against the degranulation of RBL-2H3 by antigen stimulation in a dose dependent manner at the concentrations ranging from 10 microM to 100 microM.