Study on the effect of extraction method on the quantity, quality, chemical composition and antioxidant nature of Ferulago angulata (Schlechat) Boiss. essential oil

The objective of the present study was to investigate the extraction of Ferulago angulate essential oil using the two methods of Clevenger-microwave and ultrasound, and to examine their effects on the quantity and quality of the essential oil of this medicinal plant. In the Clevenger-microwave method, the plant to water ratios of 1:10 and 1:20 and the microwave power of 330, 660 and 990 w (30,60 and 90%) were taken into account as the independent variables, while in the ultrasound method, the indirect ultrasound pretreatment (at 20 and 45°C) was considered as the affecting factors for the extraction of the essential oil of Ferulago angulate. In order to identify the chemical compounds, gas chromatography-mass spectrometry was employed and the impact of other parameters, including the efficiency, specific gravity, color, refractive index and antioxidant power of the essential oil were also valuated. It was found out that application of microwave and the rise in its power led to a decrease in the extraction initial time as well as a reduction in the extraction completion time and the time needed for the extraction curve to get constant from 4 h to 1 h. β-phellandrene had the largest content (approximately 35%). Extraction time in the microwave treatment was significantly lower than that of Clevenger.Ultrasound pretreatment at various temperatures, utilization of the Clevenger-microwave extraction method at different microwave powers and the change in the plant to water ratio did not have considerable effects on the essential oil refractive index, antioxidant activity and specific gravity