Quantitative and Qualitative Comparison of the Essential Oil of Nine Thymus Species under Agricultural Conditions

Containing valuable components such as thymol and carvacrol, the essential oil of Thymus spp is considered very important. The present study aimed at introducing Thymus species or accessions with advantages in the quantity and quality of essential oil production. For so doing, 72 accessions andnine different species ofThymus were cultivated in the Research Station of Medicinal Plants in Shahedieh Yazd. The aerial parts of plants were collected at 50% flowering stage and then were dried in shadow.The essential oils were extracted following hydro–distilled method by Clevenger apparatus for three hours. After determining the essential oil yield, based on the dry weight of the plant, the oil was identified and decomposed by Gas chromatography (GC) and chromatography-mass spectroscopy (GC/MS). Considering oil production per hectare, oil yield, and thymol percentage, the species were respectively classified as Thymus daenensis, T. vulgaris, T.transcaspicus, T.lancifolius, T. migricus, T. kotscyhanus, T.fedchenkoi, T. pubescens and T. transcaucasicus.