Characterization of Three Labdane Diterpenes fromAframomum alboviolaceum

Abstract

Two labdane diterpenes were isolated from the seeds and the rhizomes of AFRAMOMUM ALBOVIOLACEUM (Ridley) K. Schum (Zingiberaceae) and identified by GC-MS, (1)H-, and (13)C-NMR as ( E)-labda-8(17),12-diene-15,16-dial ( 1) and ( E)beta,17-epoxy-labd-12-ene-15,16-dial ( 2). A third minor compound could be the methyl ( E)-14xi,15-epoxylabd-8(17),12-dien-16-oate. The simultaneous occurrence of these three molecules has been mentioned only in one other species of the same genus, AFRAMOMUM DANIELLII (1).

Volatile Constituents of the Rhizomes ofAframomum alboviolaceum (Ridley) K. Schum. from Guinea-Bissau

“…24 and from Aframomum alboviolaceum collected in Zaõ È re. 14 The most abundant sesquiterpene was ()-intermedeol (21). Its MS-EI and MS-CI did not display the molecular ion, which was detected by single ion monitoring of ion mae 222, corresponding to the formula C 15 H 26 O. Resonance multiplicities for 13 C were established via the acquisition of DEPT spectra, whereas the concerted application of 1 H± 1 H homonuclear and 1 H± 13 C heteronuclear two-dimensional chemical shift correlation con-®rmed the presence of an eudesmane skeleton.…”