Evaluating the Effect of Essential Oil Extraction Method from Satureja macrosiphonia on Its Biological Activities: Ohmic- and Microwave-Assisted Hydrodistillation

Abstract

The aim of this study was to investigate the effect of two newly introduced extraction methods, ohmic-assisted hydrodistillation (OAHD) and microwave-assisted hydrodistillation (MAHD), on the antioxidant and antibacterial activity of the Satureja macrosiphonia essential oil. The results were compared with conventional hydrodistillation (HD). The investigated essential oils were rich in monoterpenes, notably oxygenated monoterpenes, which were represented mainly by cis-sabinene hydrate, linalool, borneol and terpinen-4-ol. The antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging assay, and the IC50 values of 13.78, 11.08 and 14.17 mg/mL was obtained for HD, OAHD and MAHD essential oils, respectively. The essential oils were also investigated against gram-positive (Bacillus cereus, Listeria innocua, Staphylococcus aureus) and gram-negative (Escherichia coli, Salmonella typhimurium, Enterobacter aerogenes) bacteria. The antibacterial activity was generally weak. In contrast to other Satureja species, Sat. macrosiphonia that was examined in this study did not exert strong biological activities. Practical Applications Application of emerging thermal technologies such as ohmic and microwave heating has been introduced to essential oil extraction and presented some desirable advantages over the conventional methods, such as effective heating, fast energy transfer, time saving and low operating costs, and no adverse alterations in chemical compositions have been observed. In this study, ohmic- and microwave-assisted hydrodistillation were used to extract the essential oils of Satureja macrosiphonia. The results of this study showed that using the emerging technologies that are considered as green technologies gives rise to a selective extraction of some components compared with hydrodistillation. Not only no adverse effect on the biological activity of the essential oils was observed, but also more extraction of particular components may result to a higher activity.