Cadinane-type sesquiterpenes induced in Gossypium cotyledons by bacterial inoculation

Two new sesquiterpenes, the cis- and trans-diastereomers of 7-hydroxycalamenen-2-one, as well as trans-7-hydroxycalamenene, have been identified in extracts from cotyledons of bacterial blight-resistant Gossypium hirsutum harvested during the period of sesquiterpenoid phytoalexin biosynthesis following inoculation with the bacterial pathogen Xanthomonas campestris pv. malvacearum. The cis- and trans-diastereomers were distinguished by NOE correlations predicted from molecular modelling calculations.