Sesquiterpenoid phytoalexins from suspended callus cultures of Nicotiana tabacum

Abstract Treatment of suspended callus cultures of Nicotiana tabacum with commercial cellulase elicited four principal stress metabolites including the phytoalexin capsidiol and a second eremophilane-type diol, shown on the basis of chemical and spectroscopic evidence to be 4-epieremophil-9-ene-11 /gx, 12-diol (without assignment of absolute configuration). This diol appears to be structurally identical with debneyol isolated from N. debneyi (see accompanying paper). Among minor metabolites were an isomer and a dehydro-analogue of the diol. GC/MS of cyclic derivatives (boronates and di- t -butylsilylene derivatives) of vicinal diols was useful for their detection and characterisation. The remaining two major metabolites appeared to be phytuberol and phytuberin.