Characterization of Melaleuca armillaris essential oil in Brazil

Abstract

The objective of this study was to propose metrics that could be used in the quality control of Melaleuca armillaris oil, extracted from plants cultivated in Brazil, to differentiate it from Melaleuca alternifolia oil. The oil was obtained by hydro-distillation using steam stripping. The physicochemical characteristics of the M. armillaris essential oil were evaluated, obtaining the following results: density 0.9146 g/mL, pH4.36, specific rotation 2.38, refractive index 1.45948, viscosity of 3 centipoises, 35901 particles ≥ 10 µm and 1743 particles between 10 and 25 µm/5 mL, moisture content 0.84% and decomposition temperature of 115.19 ºC. Osmolarity was not detected. The components of the M. armillaris oil were identified using the following techniques: gas chromatography (GC), high performance liquid chromatography (HPLC) with a mass detector, Raman and near infrared (NIR) spectroscopy. A total of 24 compounds were identified by GC, the main one being 1,8 cineole, and 145 substances were identified by HPLC. In the identification by Raman the transmittance of the oil was found to be 785 nm, and using the NIR technique, the greatest absorbance was at 2350 nm. In this way the M. armillaris oil was characterized by physicochemical analyses and its components identified.