Comparison of the volatile composition of Stachys persica Gmel. and Stachys byzantina C. Koch. oils obtained by hydrodistillation and steam distillation.

The oils obtained by hydrodistillation and steam distillation of the aerial parts of Stachys persica Gmel. and Stachys byzantina C. Koch grown in Iran were analyzed by GC/MS. The essential oil obtained by hydrodistillation of the aerial parts of S. persica was characterized by a high amount of non-terpenoid components of which methyllinoleate (27.7%), hexadecanoic acid (9.8%) and 6,10,14-trimethyl-2-pentadecanone (9.2%) were the major constituents, whereas the steam distilled oil of the plant contained hexadecanoic acid (27.2%), carvacrol (9.4%) and eugenol (5.2%). Both hydrodistilled and steam distilled essential oils of the aerial parts of S. byzantina were rich in sesquiterpenes such as a-copaene (16.6% and 10.4%), spathulenol (16.1% and 18.5%) and beta-caryophyllene (14.3% and 13.5%), respectively.