A Bioeconomically Valuable Essential Oil from Baccharis sinuata Kunth in Southern Ecuador: Chemical Composition and Enantiomeric Profile

The present research describes the chemical composition and the enantiomeric profile of a spicy green aroma essential oil, distilled from the dry leaves of <i>Baccharis sinuata</i> Kunth (Asteraceae). The distillation yield was as high as 3.0% by weight. The chemical analysis was conducted on two columns, coated with stationary phases of different polarity (5% phenyl-95% methyl polysiloxane, expressed by weight, and 100% polyethylene glycol). Major components (≥2.0% as an average value between the two columns) were as follows: β-pinene (4.9%), limonene (39.0%), (E)-β-caryophyllene (2.0%), bicyclogermacrene (2.7%), γ-cadinene (4.0%), δ-cadinene (7.3%), β-eudesmol (2.0%), α-eudesmol (3.0%), and α-cadinol (2.0%). For the enantioselective analysis, 10 enantiomeric pairs were investigated, using two capillary columns coated with different chiral selectors. As a result, (1<i>R</i>,5<i>R</i>)-(-)-α-thujene, (1<i>S</i>,5<i>S</i>)-(-)-α-pinene, and (1<i>R</i>,2<i>S</i>,6<i>S</i>,7<i>S</i>,8<i>S</i>)-(-)-α-copaene were enantiomerically pure, whereas (<i>R</i>)-(+)-limonene presented a 90.0% enantiomeric excess. All the other analysed chiral compounds were scalemic mixtures. The high distillation yield, its aroma, and the bibliographic bioactivity profile make this essential oil potentially interesting from a commercial point of view. To the best of the authors' knowledge, this is the first description of an essential oil distilled from leaves of <i>B. sinuata</i>.