Extração e caracterização do óleo essencial de tomilho (Thymus vulgaris)

Abstract

This work aim to study the chemical composition of leaves of Thymus vulgaris (thyme) using different extraction techniques. The extraction techniques used were: hydrodistillation (HD), solvent extraction (SE), supercritical fluid extraction (SFE) and solid phase microextraction (SPME). The identification of the components was performed using GC-MS. Some variables that can influence the extraction process were investigated, such as temperature profile, extraction time and choice of fiber for SPME and pressure and extraction time for SFE. The extraction methods used were effective for identifying key components present in thyme, but with some qualitative and quantitative differences. Quantitatively, the major components in all techniques were monoterpenes and sesquiterpenes. Among the conventional methods, extraction solvent obtained a higher amount of extracted components (30) when compared with hydrodistillation, with only 24 compounds. The solvent extraction showed higher concentrations of some components in Thyumus vulgaris leaves when compared with hydrodistillation. Comparing the supercritical fluid extraction and solvent extraction, the first was more efficient because obtained a greater range of extracted compounds (33) in a shorter period of time (60 min). Furthermore, the extracts obtained by SFE are free of solvent, which increases the purity/quality of the oil. The SPME is an extraction procedure easier and faster (30min), besides being even able to identify a greater number of compounds of T. vulgaris (47), when compared to other methods. Moreover, the solid phase microextraction indicated the presence of compounds β-terpinene, α- Cubebene and Cadalene. These three compounds were not mentioned in others researches with Thymus vulgaris.