Comparison of essential oil composition of three Nepeta L. species from kashan

Nepeta L. genus belongs to Labiatae family that has important medicinal and aromatic species. More than 250 species in world and 67 annual and pernnial species in Iran have been reported. In this investigation, essential oil composition of Nepeta gloeocephala Rech. f., Nepeta sessilifolia Bunge and Nepeta laxiflora Benth have been staudied. The species are endemic to Iran and have natural habitats in Dorien, Ghohroud and Mashhad-e-ardahal of Kashan. The flowering branches of these species were collected in spring and summer and dried in shade (at room temperature). The flowering branches of the species subjected to volatile fraction were isolated by hydrodistillation using a Clevenger-type apparatus for 3 or 4 hours. After decanting and drying of the oils over anhydrous sodium sulfate, they were stored in vial at low temperature (4ºC) before analysis. The analysis of the oils was performed using GC and GC-MS. The results showed that, the essential oil of Nepeta gloeocephala Rech. f. was yellow in 1/3% (v/w) yield and 29 components were identified, among them, 1,8-Cineole (35.2%), Beta-pinene (21.8%), sabinene (7.8%), (E)-beta ocimen (7.1%), alpha-pinene (7.1%) and (Z)-ocimene (6.9%) were the major compounds. The essential oil of Nepeta sessilifolia Bunge was bright yellow in 0.65% (v/w) yield and 33 components were characterized, among them, spathulenol (25.8%), lavandulyl acetate (16.7%), limonene (6.4%) and geranyl acetate (4.17%) were identified. The essential oil of Nepeta laxiflora Benth was sharp yellow in 0.175% (v/w) yield and 30 components were identified, among them, alpha-pinene (19.7%), 1,8-cineole (11.8%), alpha-bisabolol (6.9%), delta-cadinene (6.8%), germacreneD-4-ol (6.2%), and caryophyllene oxide (4.4%) were main compounds.