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

Francisco José de Abreu Matos,G. S. R. Subba Rao,Paulo Roberto Oliveira Lopes,Márcio Tavares Holanda,Maria Goretti de Vasconcelos Silva,Fábio Oliveira Silva

doi:10.3998/ark.5550190.0005.609

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 CO2 (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.

Highlights

The specialized literature has registered since many years the yields and chemical composition of several essential oils obtained by steam distillation, hydrodistillation and, more recently, by supercritical liquids extraction.According to the literature there are two chemical types of O. gratissimum L. in function of the main compounds in the essential oils from their leaves, the thymol type and the eugenol type
The essential oils of O. gratissimum show eugenol and 1,8-cineole as major constituents of leaves extracted by the three processes (Table 1), the presence of α-selinene, β-selinene, γ-muurolene, α-humulene and (E)-β-caryophyllene have been observed in all samples studied but in lesser relative amounts
The oils from O. micranthum showed larger variability, only three compounds were common in the studied samples: eugenol, (E)-β-Caryophyllene and elemicin

Summary

Introduction

The specialized literature has registered since many years the yields and chemical composition of several essential oils obtained by steam distillation, hydrodistillation and, more recently, by supercritical liquids extraction.According to the literature there are two chemical types of O. gratissimum L. in function of the main compounds in the essential oils from their leaves, the thymol type and the eugenol type. Abstract Essential oils (EO) from leaves of Ocimum gratissimum L., Ocimum micranthum Willd. Obtained by steam distillation (SD), microwave oven distillation (MO) and supercritical extraction with CO2 (SC) showed different composition by GC/MS analysis.

Results

Conclusion