Structural and biosynthetic studies on eremophilenols related to the phytoalexin capsidiol, produced by Botrytis cinerea

A thorough study of the fermentation broth of three strains of Botrytis cinerea which were grown on a modified Czapek-Dox medium supplemented with 5 ppm copper sulphate, yielded five undescribed metabolites. These metabolites possessed a sesquiterpenoid (+)-4-epi-eremophil-9-ene carbon skeleton which was enantiomeric to that of the phytoalexin, capsidiol. The isolation of these metabolites when the fungus was stressed, suggests that they may be potential effectors used by B. cinerea to circumvent plant chemical defences against phytopathogenic fungi. The biosynthesis of these compounds has been studied using 2H and 13C labelled acetate. Five eremophilenols isolated from Botrytis cinerea may be effectors used to circumvent plant chemical defences. The biosynthesis of these compounds has also been studied. [Display omitted] •Three strains of B. cinerea cultured with 5 ppm of copper sulphate were studied.•Five cryptic metabolites with skeletons enantiomeric to that of capsidiol were identified.•These eremophilenols may be effectors used to circumvent plant chemical defences.•The biosynthesis of 4-epi-eremophil-9-enols has been proposed.