Stilbenes, monoterpenes, diarylheptanoids, labdanes and chalcones from Alpinia katsumadai

The aerial parts of Alpinia katsumadai yielded six novel compounds, including 1-(1-terpinen-4-olyl)-3-methoxystilbene (E) (1), a mixed metabolite comprising elements from the stilbene and menthane monoterpene classes; the stilbenes 3-methoxy-5-hydroxystilbene (Z) (7) and 3,5-dihydroxystilbene (Z) (8); the diarylheptanoids 5-hydroxy-1-(4'-hydroxyphenyl)-7-phenyl-hepta-6-en-3-one (10) and trans-3,5-dihydroxy-1,7-diphenyl-hept-1-ene (12b); and a mixed metabolite (13) comprising elements from the chalcone and labdane diterpene classes of natural products. Several known representatives of each of these classes of natural product were also isolated. The structures of the novel compounds were determined by 2D NMR spectroscopy and NMR assignments of several of the known compounds, deduced by the same methodology, are reported for the first time. (C) 1998 Elsevier Science Ltd. All rights reserved.