A new sesquiterpene from South African wild ginger (Siphonochilus aethiopicus (Schweinf) B.L. Burtt)

A new eusdesmane sesquiterpenoid, characterised as 5-acetoxy-9aβ-hydroxy-4aαH-3,5α, 8aβ-trimethyl-4, 4a, 6, 7, 8a, 9-hexahydronaphtho-([2, 3 b]-dihydrofuran-2-one)-8-one or phaeusmane F acetate (1) has been isolated from the rhizomes of the South African variety of wild ginger (iphonochilus aethiopicus (Schweinf) B.L. Burtt). The compound was obtained after a series of column and gel filtration chromatography. Its structure was elucidated by NMR and Mass-Spectrometric analyses, including 1 D-, 2 D-NMR and HR-LCMS. This is an initial report of the compound from a Siphonochilus sp. Previously isolated similar compounds from the plant material were 4aαH-3,5α,8aβ-trimethyl-4,4a,8a,9-tetrahydronaphtho[2,3b]-furan-8-one (siphonochilone) (2), 9aβ-hydroxy-4aαH-3,5α,8aβ-trimethyl-4,4a,8a,9-tetrahydronaphtho-([2,3b]-dihydrofuran-2-one)-8-one (3), 4aαH-3,5α,8aβ-trimethyl-4,4a,8a,9-tetrahydronaphtho-([2,3b]-dihydrofuran-2-one)-8-one (4), 2-hydroxy-4aαH-3,5α,8aβ-trimethyl-4,4a,8a,9-tetrahydro-naphtho[2,3b]- furan-8(5H)-one (5), 4aαH-3,5α,8aβ-trimethyl-4,4a,8a-trihydronaphtho-([2,3b]-dihydrofuran-2-one)-8-one (6).[Formula: see text].