Fungicidal sesquiterpene dialdehyde cinnamates from Pseudowintera axillaris.

Bioactivity-directed separation of a foliage extract from the New Zealand shrub Pseudowintera axillaris led to a compound with fungicidal activity against the plant pathogen Phytophthora infestans. This was identified as a new sesquiterpene dialdehyde cinnamate named paxidal. Two 6-hydroxy derivatives were present at lower levels in the extract.

Sesquiterpenes from the New Zealand Liverwort Lepidolaena hodgsoniae.

NMR studies have shown that seven new sesquiterpenoids, 3, 4, 5a, and 7-10, isolated from dried samples of the New Zealand liverwort Lepidolaena hodgsoniae have the same substituted cyclopentapyran ring system as the previously described insecticidal sesquiterpene diene hodgsonox (1), which has been reported only from this plant. In all but one compound, 10, the 1,1-disubstituted double bond of hodgsonox has migrated into an endocyclic position, but only two, 5a and 9, have the double bonds in conjugation. These seven new compounds represent a variety of different oxidation levels.

Biosynthesis of the sesquiterpene hodgsonox from the New Zealand liverwort Lepidolaena hodgsoniae.

The incorporation of [1-13C] labelled glucose into hodgsonox, a sesquiterpene epoxide with a unique, doubly allylic ether functionality has been studied in axenic cultures of the liverwort Lepidolaena hodgsoniae. Quantitative 13C NMR spectroscopic analysis showed that the isoprene units are derived exclusively from the methylerythritol phosphate pathway.