Composition of the Volatile Oils of Three Different Species of Artemisia

1. Introduction

     The large genus Artemisia (Compositae) comprising about 300 species is widely distributed in various parts of the world, south west America, South Africa, Europe and mainly Asia [1, 2]. Thirty-four species of these plants are growing wildly in various parts of Iran, including north of Khorasan province, northeast of Iran [3]. The common name of the genus Artemisia in Iran is “Dermaneh”, but these plants locally called “Terekh” in Khorasan province [3-5]. Most of the Artemisia species are medicinal herbs, which have had several uses in the folk medicine all over the world. There are several reports on the pharmacological effects of this herb, i.e. carminative, antipyretic, antiparasitic, anthelmintic, antiseptic, antispasmodic, antimicrobial, anti-inflammatory, appetite stimulating, digestive, funguicidal, emmenagogue, stomachic, vermifuge, vulnerary, and hypnotic [1, 4-6].

     The chemical composition of the essential oils and plant extracts of several Artemisia species has been the subject of many investigations [7-9]. However, there is no report on the chemical composition of the oils of these plants growing in Khorasan province, northeastern Iran. Since the chemical composition of the volatile oils depends on various environmental conditions and varies from one species to another [10, 11], it was, therefore, of great interest to investigate the chemical constituents of the oils of three different Artemisia species, A. scoparia Waldst. and Kit, A. diffusa Krasch. Ex Poljak and A. turanica Krasch, growing in this area.

2. Materials and methods

2.1. Plant material

      Artemisia scoparia Waldst. and Kit was collected from the campus of Ferdowsi university of Mashhad, Khorasan province, Iran, in August 2003. Artemisia diffusa Krasch. ex Poljak and Artemisia turanica Krasch were collected from the Marzdaran region (northern Khorasan province, Iran), in November 2002. Professor Ghoraishi Al-Hossainy, Botany Department, Faculty of Sciences, Ferdowsi University, Mashhad, identified the plants. Voucher specimens are deposited in the Herbarium of Ferdowsi University.

2.2. Isolation of the volatile components

      The aerial parts of each of the three different Artemisia species, (A. scoparia, A. diffusa and A. turanica) were collected, airdried, and powdered. The oils were isolated from powdered plant materials by wet steam distillation for 4 h [26]. The essential oils were separated from the aqueous layer, dried over anhydrous sodium sulfate and were stored in the refrigerator until analyzed.

2.3. Gas chromatography-mass spectrometric analysis

     The GC-MS analysis of the essential oils of three different Artemisia species (scoparia,diffusa, turanica) were carried out on a Varian Saturn 3 GC-MS spectrometer and the oils were analyzed under the following operating conditions: column DB-5, 0.32 mm × 30 m (J & W Scientific); carrier gas, He; flow rate 2 ml/min; oven temperature: 60-240 ºC with rate of 3 ºC/min; injector mode: split injection; ionization mode: electron impact (EI) at 70 eV; interface temperature: 270 ºC; scan range 40-300 u.

     The identification of the essential oil components was performed by comparison of their relative retention time (RRT) and their mass spectra with those of authentic samples, literature data [13], and computerized MS-data bank (Saturn, version 4). The peak area method was followed for quantitative determination of different constituents; the percentage was calculated relatively [13].

3. Results

      The wet steam distillation of the aerial parts of Artemisia scoparia, A. diffusa and A. turanica, gave clear yellow oils with a strong characteristic odor. On a dry weight basis, they yielded 0.32% (v/w), 0.28% (v/w), and 0.30% (v/w) of volatile oils, respectively. GC-MS analysis was used for the identification of components of the volatile oils. Twenty-two compounds (Table1) were identified in the oil of A. scoparia (91.7% of the total composition) and twentysix compounds (Table 2) were identified in the oil of A. diffusa (94.43% of the total composition of the oil). In the oil of A. turanica, only 13 compounds were identified making up 86.43% of the total composition (Table 3).

4. Discussion

           The analysis of the essential oils isolated from aerial parts of A. scoparia, A. diffusa, and A. turanica, carried out by GC-MS, lead to the identification of different components.

     The identified compounds and their percentages are listed according to their elution on the DB-5 column given in Tables 1, 2, and 3, respectively. Twenty-two compounds were identified in the oil of A. scoparia making up 91.7% of the total composition.

Table 1. Chemical composition of the volatile oil of Artemisia scoparia.

t = trace (< 0.1 %)

Table 2. Chemical composition of the volatile oil of Artemisia diffusa.

t = trace (< 0.1 %)

Table 3. Chemical composition of the volatile oil of Artemisia turanica.

     Monoterpene hydrocarbons represented the most abundant constituents of the volatile oil of A. scoparia (54.56%). The oxygen containing monoterpenoids, identified in the oil of this plant, were 24.12%. The amounts of the sesquiterpenoid hydrocarbons and oxygen containing sesquiterpenoids were both at relatively low levels in the oil of A. scoparia (5.35% and 7.67%, respectively). No nonterpenic constituents were detected in the essential oils. The major components in the volatile oil of A. scoparia were b-pinene (16.10%), carvacrol (13.81%), limonene (8.82%), cis-ocimen (8.38%), methyl eugenol (7.62%) and transocimene (7.17%).

     Twenty-six compounds were identified in the oil of A. diffusa, which represented about 94.43% of the total composition of the oil. In the volatile oil of A. diffusa, the oxygen containing monoterpenoids represented the  most  abundant  constituents  (92.59%).

     Monoterpene hydrocarbons, identified in the oil of this plant, were at low level (1.53%). No sesquiterpenoid hydrocarbons were identified in the oil, while oxygenated sesquiter- penoids were at very low level in the oil of A. diffusa  (0.76%).  No  nonterpenic  con- stituents were also detected in the essential oil of this plant. However, camphor (25.5%),1,8-cineol (25.0%), β-thujone (22.0%), and α-thujone (6.93%) were the major compo- nents identified in the volatile oil of A. dif- fusa. In the oil of A. turanica, only 13 com- pounds were identified making up 86.43% of the total composition. The major compo- nents in the volatile oil of this plant were1,8-cineol  (40.94%),  cis-verbenyl  acetate (19.03%),  and  camphor  (11.03%).  The volatile oil of A. turanica is very rich in oxy- gen  containing  monoterpenoids  (76.32%), while it is quite poor in monoterpene hydro- carbons (3.04%). Although there are some oxygenated sesquiterpenoids in the essential oils of this plant (6.32%), there is not a sig- nificant amount of  sesquiterpenoid hydro- carbons  in  the  oil.  No  nonterpenic  constituents were detected in the essential oils.

     The components identified and their percentages from the essential oils of three different Artimisia species in this study were quite different. The components identified were also different with previous reports [7,10]. Since the chemical composition of the essential oils of plants can be influenced by the environmental factors, and it is varied among species, therefore, these differences can be expected.

Acknowledgments

The  authors  would  like  to  thank  the authorities  of  the  Faculty  of  Pharmacy, Mashhad University of Medical Sciences for its financial support.