Gnetins in Welwitschia

A wood sample of Welwitschia mirabilis is reported to contain nerolidol and para-hydroxybenzaldehyde, besides two dehydroresveratrol dimers gnetins F and G and two dehydroresveratrol trimers gnetins H and I for which structures are proposed. Other oxidative resveratrol oligomers, gnetins A, B, C, D and E, have been isolated previously from three Amazonian Gnetum species. These facts provide welcome evidence for the discussion of relationships within the Gnetatae.