Chemical compositions of essential oil from the aerial parts of male and female plants of <i>Baccharis tridentata</i> Vahl. (Asteraceae)
Manuel Minteguiaga, Laura Fariña, Eduardo Cassel, Stephanie Fiedler, César A.N. Catalán, Eduardo Dellacassa
Abstract
Differences in female/male plant metabolism for dioecious species are poorly understood but relevant if the economic exploitation of such resources is the objective. In this work, the composition of Baccharis tridentata Vahl essential oil from the flowering aerial parts of male and female plants was analysed separately by GC-MS (gas chromatography-mass spectrometry; area percentage and internal standard), and CPGC-MS (chiral phase gas chromatography analysis using modified β-cyclodextrin), reporting the enantiomeric distribution of monoterpene hydrocarbons as a genuineness criterion. The results confirmed high qualitative similarities between the essential oils from both genders, but quantitative differences in the main components α-pinene, β-pinene, limonene and bornyl acetate. Regarding the CPGC-MS analysis of monoterpene hydrocarbons, both sexes presented both enantiomers in the same ratios, which is in contrast to the values reported in the literature for related plants. However, natural bornyl acetate (isolated from B. tridentata essential oil) demonstrated a 100% enantiomeric excess of the levogyre enantiomer, a fact that has chemotaxonomic relevance.