Composition of essential oils from three Ocimum species obtained by steam and microwave distillation and supercritical CO2 extraction

Abstract

Essential oils (EO) from leaves of Ocimum gratissimum L., Ocimum micranthum Willd. and Ocimum selloi Benth. obtained by steam distillation (SD), microwave oven distillation (MO) and supercritical extraction with CO 2 (SC) showed different composition by GC/MS analysis. The main components in the three essential oils were the same but in different relative amounts. The oil from O. gratissimum obtained by SD presented eugenol (54.0%) and 1,8-cineole (21.6%) as main components, by MO eugenol (34.6%) and 1,8-cineole (22.6%), and by SC eugenol (73.1%) and 1,8-cineole (5.6%). The essential oil from O. micranthum obtained by SD showed mainly eugenol (64.8 %), (E)-β-caryophyllene (14.3%) and bicyclogermacrene (8.1%); by MO eugenol (30.6 %), trans-β-caryophyllene (19.8 %) and elemicin (19.0), and the oil obtained by SC presented eugenol (56.7%), elemicin (16.0%) and trans-β-caryophyllene (4.0%). Essential oil of O. selloi obtained by SD presented anethole (64.6%) and linalool (20.6%); by MO anethole (67.4%) and linalool (20.9%) and by SC anethole (31.9%) and linalool (23.2%) as main constituents. The type and quantitative variations of the chemical components of the analyzed oils in relation to the extraction methods were greater for O. micranthum.