[The chemical constituents of Goniothalamus howii Merr].

Two new compounds were isolated from the chloroform soluble fraction of ethanolic extract of bark of Goniothalamus howii Merr. On the basis of their chemical properties and spectral data (MS, UV, IR, 1H and 13CNMR) they were identified as 6S (1R-hydroxy-2R-cinnamyloxyphenethyl) 5, 6-dihydro-5S-hydroxy-2-pyrone named Howiinol A and 6S-(1S, 2R-epoxyphenethyl-5S-cinnamyloxy) 5, 6-dihydro-2-pyrone named Howiinin A. Howiinol A showed significant antitumor activities toward human tumor cell in vitro and in vivo and less toxic.