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, 1H-, and 13C-NMR as (E)-labda-8(17),12-diene-15,16-dial (1) and (E)β,17-epoxy-labd-12-ene-15,16-dial (2). A third minor compound could be the methyl (E)-14ξ,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).