A note on the volatile secondary metabolites of Foeniculum vulgare Mill. (Apiaceae)

Abstract

An anal. (GC and GC/MS) of Foeniculum vulgare Mill. (fennel) root and schizocarp essential oils and di-Et ether exts. enabled the identification of 89 different components, representing 98.2-100% of the total samples. One fourth of the identified compds. (24 in total) are reported for the first time as fennel volatiles. The most abundant classes of constituents of all four analyzed samples were the phenylpropanoids (69.5-85.5%) and monoterpenoids (11.7-26.9%). The dominant volatile metabolites of the schizocarps were fenchone (13.3-18.8%) and (E)-anethole (66.1-69.0%). Contrary to that, terpinolene (6.2-6.5%) and dillapiole (71.4-77.5%) were the major volatiles of fennel roots. The most striking differences between the chem. compn. of the analyzed oils and their corresponding exts. were a rather surprising presence of a significant relative amt. of apiole in the root oil (9.3%; this compd. was detected only in trace amts. in the root ext.) and the high percentage of 10-nonacosanone in the schizocarp ext. (5.8%; this ketone was absent from the schizocarp oil). Possible explanations of the mentioned differences were put forward. The AMS (av. mass scan of the total ion chromatogram) profiles/fingerprints of the volatile oils and exts. of F. vulgare roots and fruits are also given in the paper. [on SciFinder(R)]