Comparison of Four Extraction Methods for Essential Oil from Thymus daenensis Subsp. Lancifolius and Chemical Analysis of Extracted Essential Oil

The air dried aerial parts of Thymus daenensis were subjected to extract the essential oil (EO) using hydrodistillation (HD), ohmic (O), ultrasound‐assisted hydrodistillation (UAHD) and ultrasound‐assisted ohmic (UAO) extraction methods. The influence of applied different extraction methods on extraction parameters, microstructure of oil glands and chemical properties of extracted EO were investigated. Hydrodistillation and ultrasound‐assisted ohmic extraction methods showed the longest and the shortest extraction onset time, and ultrasound‐assisted hydrodistillation and ohmic extraction methods showed the most and the least extraction efficiency (W/W), respectively. Moreover, hydrodistillation and ultrasound‐assisted ohmic extraction produced the least and the most essential oils yield, respectively. According to obtained gas chromatography‐mass spectrometry (GC‐MS) analysis of extracted T. daenensis EO based on the method of extraction, quantitatively different, among 37 detected, compounds were observed. Extraction methods showed significant effects on different extraction parameters while ultrasound treatment had no significant effect except on extraction efficiency of hydrodistillation. Practical Application Among the novel extraction methods application of ultrasound and ohmic attracted lots of attentions due to a short time and enough extraction efficiency. Comparison the novel methods and their possible effects of chemical structure of extracted essential oil could provide useful information in the term of possibility of approach about other similar essential oil. Application of the novel proposed methods in combination of conventional or as alternative in order to increase the extraction rate in industrial scale could be recommended.