Albert Stoessl

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.

Effects of orchinol and related phenanthrenes on the enzymic degradation of indole-3-acetic acid

Abstract Orchinol, hircinol, loroglossol and certain related phenanthrenes inhibited horseradish peroxidase-catalysed IAA degradation to a varied degree. Among

The stereochemistry of the biosynthetic precursor of gossypol

cis-trans-Farnesyl pyrophosphate or an equivalent such as nerolidyl pyrophosphate in contrast to earlier work, has been established, through [1,2-13C2]acetate feeding, as the main biosynthetic precursor of gossypol in chilled cotton (Gossypium arboreum) radicals.

Metabolites of part V. Biosynthesis of altersolanol A and incorporation of altersolanol A-13Cx into altersolanol B and macrosporin ☆

Abstract The biosynthesis of the tetrahydroanthraquinone, altersolanol A ( 1 ), by Alternaria solani has been established by the incorporation of [1,2-13C2]-acetate. A blocked culture of A. solani was utilized to reveal that 1 is metabolized to altersolanol B and macrosporin.

New phenolic inhibitors of the peroxidse-catalysed oxidation of indole-3-acetic acid

Abstract Previously we reported two metabolites of the insecticide carbofuran as persistent inhibitors of the peroxidase-catalysed oxidtion ofindole-3-acetic acid. In searching for more active inhibitors of this type, we have found that 5-hydroxy-2,2-dimethylchromene (β-tubanol), 2′,6′-dihydroxycetophenone oxime, 5-hydroxy-2,2-dimethylchroman, 2′,6′-dihydroxyacetophenone and 2,6-dihydroxybenzoic acid methyl ester were more active than the carbofuran metabolite 7-hydroxy-2,2-dimethyl-3-oxo-2,3-dihydrobenzofuran. Resorcinol, 5-hydroxy-2,2-dimethylchroman-4-one, 3-hydroxy-5-methoxy-2,2-dimethylchroman-4-one and 5-hydroxy-2-methylchrom-4-one were also inhibitory but with less activity. The new inhibitors differed from the well-known phenolic inhibitors such as caffeic acid in inhibition kinetics as demonstrated by the rate of disappearance of indole-3-acetic acid, the rate of formation of the oxidation products, and the transient spectral change in the enzyme.

The biosynthesis of 2,7-dihydroxycadalene in infected cotton cotyledons: the folding pattern of the farnesol precursor and possible implications for gossypol biosynthesis

Incorporation of [1,2-13C2]acetate into the cotton phytoalexin 2,7-dihydroxycadalene by bacteria-inoculated cotton seedling has established a folding pattern for its carbon skeleton which differs from that deduced for the other cotton phytoalexin gossypol by earlier 14C studies.

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.

The marticins: Evidence for a mixed origin from the polyketide and tricarboxylic acid pathways by [2-13C1] and [1,2-13C2]- acetate incorporation experiments

Abstract 13 Cmr spectra of the methyl ester of marticin, biosynthetically enriched with 13 C frm [2- 13 C 1 ] and [1,2- 13 C2 2 ]acetate, indicate a mixed biogenesis from a heptaketide and a Krebs cycle acid.

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.