E. W. B. Ward

Sesquiterpenoid stress compounds of the solanaceae

Abstract The sesquiterpenes isolated from species of the Solanaceae under various conditions of stress are reviewed, with brief references to other solanaceous stress metabolites. The chemistry and selected physical properties of the sesquiterpenoidal compounds are summarized with special emphasis on their 1H and 13C NMR spectra. The close biogenetic relations between the compounds are discussed, and their possible biological function as antifungal agents (“phytoalexins”) is considered.

The Structures of some Stress Metabolites from Solanummelongena

The structures of the acyclic sesquiterpenes 1–5 and the bicyclic sesquiterpenes 6 and 7, all isolated from eggplant fruit inoculated with fungi, were elucidated with the aid of 1H and 13C n.m.r. studies. Trienone 1 was found to be identical to 9-oxonerolidol from camphor leaf oil while 2 and 3 are isomeric alcohols derived from 1. Compounds 4 and 5 are probably artifacts. The hydroxyaldehyde 6 is identical with the potato phytoalexin lubimin, originally represented by a structure shown here to be incorrect. Enone 7 is a novel eudesmane. The stereochemistries of these compounds are discussed.

Lubimin: a phytoalexin of several Solanaceae. Structure revision and biogenetic relationships

A new structure proposed for the phytoalexin, lubimin, correlates it biogenetically with other bicyclic sesquiterpenes of the Solanaceae.

Sesquiterpenoid stress compounds of Datura stramonium: biosynthesis of the three major metabolites from [1,2-13C]acetate and the X-ray structure of 3-hydroxylubimin

2,3-Germacrenediol, lubimin, and hydroxylubimin, the major stress metabolites of Datura stramonium, incorporate sodium [1,2-13C]acetate in patterns, as shown by 13C n.m.r. spectroscopy, which establish their structures and mevalonate origins; the X-ray structure of hydroxylubimin completely defines its stereochemistry.

A 2,3-dihydroxygermacrene and other stress metabolites of Datura stramonium

A 2,3-dihydroxygermacrene (3) has been isolated together with lubimin, hydroxylubimin, and capsidiol from Datura stramonium and is of interest as a possible biogenetic precursor for several stress metabolites of the Solanaceae.

Coprinolone, an oxygen-bridged protoilludane from the fungus Coprinus psychromorbidus: structure determination by chemical and n.m.r. studies aided by biosynthetic incorporation of [1,2-13C2]acetate

The structure of a sesquiterpene ketol, coprinolone, from the W2 isolate of the fungus Coprinus psychromorbidus, has been deduced as (1a) by chemical transformations and from 1H and 13C n.m.r. data; confirmation was obtained from the labelling pattern of the compound from cultures supplemented with [1,2-13C2]acetate.