F. Sefidkon* and Z. Jamzad

Abstract: Essential oils from aerial parts of Nepeta cephalotes Boiss., N. bornmuelleri Hausskn. ex Bornm., N. mirzayanii Rech. f. et Esfand. and N. bracteata Benth. were obtained by hydrodistillation. The oils were analyzed by capillary gas chromatography, using flame ionization and mass spectrometric detection. Eight components were identified in the oil of N. cephalotes with 4aα,7α,7aα-nepetalactone (90.1%) and β-pinene (7.5%) as main constituents. Twenty-eight compounds were identified in the oil of N. bornmuelleri with 4aβ,7α,7aβ-nepetalactone (64.0%) and 1,8-cineole (7.1%) as main components. Twenty-two compounds were characterized in the oil of N. mirzayanii with 4aα,7α,7aα-nepetalactone (61.0%) and caryophyllene oxide (7.8%) as main constituents. Twenty-eight compounds were characterized in the oil of N. bracteata with spathulenol (14.0%), caryophyllene oxide (12.3%), bicyclogermacrene (11.4%) and β-caryophyllene (11.2%) as main constituents. The results showed the nepetalactone isomers were the main components of the oils of N. cephalotes, N. bornmuelleri and N. mirzayanii. The oil of N. bracteata consisted of mainly of sesquiterpenes, while nepetalactone was not detected in this oil.

Nepeta L. (Lamiaceae) contains about 300 species, which are distributed in central and southern Europe, the Near East, and central and southern Asia. Iran is one of the centers of origin of the genus with 75 species of which approximately 53% are endemic (1). In this research we studied the essential oil composition of four native species of Nepeta (N. cephalotes Boiss., N. bornmuelleri Hausskn. ex Bornm., N. mirzayanii Rech. f. et Esfand. and N. bracteata Benth.), three of which are endemic. Nepeta bracteata grows wild in Iran and some other area of Asia like western sought. The feline attractant properties of several Nepeta spp. have been known for a long time. The extracts of many Nepeta species are used in domestic medicines (2). Nepeta cataria L. (2), commonly known as catnip, is the most intensively studied species. It is used as a fortifier, a disinfectant and a cure against cold. The extracts of some species are also used because of their diuretic properties and slight bacteriostatic activity, and in ointments to heal skin disorders of eczema type (2). Most oils of Nepeta species contain nepetalactones as the main components, but different oil compositions have been detected in several Nepeta species like N. discolor (3), N. govaniana (4), N. italica (5) and N. cilicia (6). Because of the interesting biological activities of the Nepeta species and their use in folk medicine, we were interested to study the essential oil content and composition of Nepeta species in Iran. The oil composition of some Nepeta species of Iran, N. glomerulosa Boiss. (7), N. pogonosperma Jamzad et Assadi (8), N. crassifolia Boiss. et Buhse (9-10), N. meyeri Benth. (11), N. fissa C.A. Mey (12), N. racemosa Lam. (13), N. macrosiphon Boiss (14), N. ispahanica Boiss and N. binaludensis Jamzad (15) and N. persica Boiss (2) were reported previously. The major components of N. glomerulosa were α-pinene (9.4%), geranyl acetate (9.3%) and limonene (8.2%), while that of N. pogonosperma were 4aα,7α,7aβ-nepetalactone (57.6%) and 1,8-cineole (26.4%). The main constituents of the essential oil of N. meyeri were 4aα,7α,7aβ-nepetalactone (53.2%) and 1,8-cineole (29.3%). The main constituents of the oil of N. fissa were β-caryophyllene (17.4%) and caryophyllene oxide (12.3%), while that of N. crassifolia was 4aα,7α,7aα-nepetalactone (92.6%). The main components of N. racemosa oil were 4aβ,7α,7aβ-nepetalactone (33.6%), 4aα,7α,7aβ-nepetalactone (25.6%) and 4aα,7α,7aα-nepetalactone (24.4%). Nepetalactone was also the main compounds in the oils of N. ispahanica, N. binaludensis and N. persica. The major components of N. macrosiphon were spathulenol (14.1%) and germacrene D (9.2%). The main components of the oil of N. cephalotes were 4aα-7α-7aα-nepetalactone (35.1%), β-pinene (18.2%) and 1,8-cineole (11.4%) (16). A review of the literature reveals that the oils of N. bornmuelleri, N. mirzayanii and N. bracteata have not been the subject of previous studies.