Essential oil of Tanacetum dumosum as a new source of fragranol

Abstract

Tanacetum (tansy) belongs to the tribe Anthemideae, which is one of the largest tribes of Asteraceae family, comprising about 111 genera and ca. 1800 species worldwide [1]. In the flora of Iran, this genus is represented by 31 annual and perennial species, of which 15 are endemic [2]. The essential oils of several Iranian tansies, including T. bachtiaricum Mozaff. [3], T. fruticulosum Ledeb. [4], T. canescens and T. turcomanicum [5], and T. polycephalum Schultz-Bip. [6], were analyzed by different authors and found to have monoterpenoids as major constituents. Among them, pinenes, 1,8-cineol, camphor, chrysanthenol derivatives, and thujones are detected more frequently. In addition to the above regular monoterpenoids, irregular monoterpenes such as artemisia ketone, santolina triene, and yomogi alcohol are found in some tansy species, including T. kotschyi [7] and T. santolinoides [8]. To the best of our knowledge, this is the first report on characterization of the chemical composition of the essential oil of T. dumosum. The aerial parts of Tanacetum dumosum Boiss. were collected from Dena mountain at an altitude of 3200 m in July 2011. The plant material was identified by one of us (MA), and a voucher specimen (No. PC-87-113) was deposited at the herbarium of our institute (MNCRS), Shiraz, Iran. The essential oil of the leaves and flowers of the plant (70 g) was extracted by hydrodistillation to yield 0.2 mL of pale-yellow oil, dried over anhydrous sodium sulfate, and analyzed by gas chromatography-mass spectrometry (GC-MS) and GC-flame ionization detector (GC-FID). Twenty seven monoand sesquiterpenoids were identified in the oil using GC retention indices (RRI) and mass spectral (MS) data, obtained from GC and GC-MS experiments, and comparison of these data to those reported for the standard volatiles in the literature [9, 10] (Table 1). Among them, the monoterpene hydrocarbons santolina triene (2.2%) and -pinene (2.2%) and the oxygenated monoterpenes fragranol (26.7%), 1,8-cineol (5.7%), fragranyl acetate (23.6%), and trans-carvyl acetate (10.1%) were detected as the major constituents. Helifolenol A, -sesquiphellandrene, caryophyllene oxide, and germacrene D are the major sesquiterpenes detected in this oil, but they are still in smaller quantities compared to the monoterpenoids fraction (Table 1). Fragranol, the E isomer of 2-isopropenyl-1-methylcyclobutane ethanol, was reported previously in the oils of Achillea santolina [9], A. nobilis [11], and A. falcata [12], but to the best of our knowledge for the first time in tansy species. Previously, fragranol was reported by one of us (ARJ) in the oil of Artemisia haussknechtii [13], a member of Anthemideae, which grows nearby T. dumosum. Grandisol, the Z-isomer of fragranol, is reported to be an aggregation and sex-attractant pheromone for several weevil insects [14, 15], and recently together with camphor and 1,8-cineol as the major constituent of an anti-insect essential oil of Artemisia vestita [16]. The antibacterial and insecticidal activity of the essential oils of the above plant species with similar chemical composition reported here for T. dumosum suggests that this plant is a potential medicinal plant to be explored in the future [9, 11, 12]. The good smell of the plant may be due to the presence of fragranol and its acetate ester and suggests that this plant can be used in the perfume industry. GC-MS and FID Analyses. GC-MS analysis was carried out on an Agilent 7890A GC coupled to an HP-6890 mass spectrometer operating in EI mode at 70 eV. The GC was equipped with a J&W DB-5 ms Scientific column (30 m 0.25 mm i.d., 0.25 m film thickness). The oven temperature was programmed from 60 C to 220 C at 5 C/min and kept for 10 min at 220 C. The carrier gas was helium (He) with a flow rate of 1 mL/min, and the injector temperature was set at 260 C in the split mode for the pure essential oil (1:100). The injection volume was 0.1 L. The GC-FID analysis was performed using the above instrument coupled to a FID with the same analytical conditions, but the column was replaced by a DB1 column with the same dimension as that used in GC-MS with the temperature of the FID set at 260 C.