[Antianaphylactic components of Asarum forbsii Maxin].

From the ethyl acetate extract of Asarum forbesii Maxin, four new constituents, asarumin A(I), B(II), C(III) and D(IV), were isolated along with elemicin (V), trans-asarone(VI) and linoleic acid(VII). The structures of the new compounds were elucidated as methyl 3 S-benzoyloxy-2 S-hydroxy-2-isopropylbutyrate for I, methyl 2 R-benzoyloxyisopentanoate for II, methyl 2 R-trans-cinnamoyloxyisopentanoate for III and methyl 2 R-piperonyloyloxyisopentanoate for IV. Compounds I, II, III and VII showed weak inhibition of PCA in rats, but the other compounds were inactive.