Ferulagone: a new monoterpene ester from Ferulago thirkeana essential oil

Essential oil obtained by micro-distillation and hydrodistillation of the endemic Ferulago thirkeana (Boiss.) Boiss. (Apiaceae) was analysed by GC/MS. An unknown component isolated from the essential oil was characterized by chromato-spectral techniques (1D-, 2D-NMR, HRMS, IR and UV) as (1 S)-2,6,6-trimethyl-4-oxobicyclo[3.1.1]hept-2-enyl(2 E)-2-methylbut-2-enoate (= ferulagone or 1-angeloyloxyverbenone) (1). Biological activities of the essential oil and the purified major component (1) were tested against various human pathogenic microorganisms resulting in moderate inhibition (62.5 - 125 microg/ml).