The genus Achillea L. (Asteraceae) is represented by about 115 species found in the Northern Hemisphere, mostly in Europe and Asia, and commonly known as yarrows.1-3 It has been represented in Iran by nineteen species including seven endemics.4 The Achillea L. species belong to the oldest medicinal plants that are used both for pharmaceutical purposes and in folk medicine. These plants contain a complex of different pharmacological compounds like terpenes, flavonoids, alkaloids, bitters, tannins, lignans, etc.5 Achillea species are diuretic, emmenagogue agents, used for healing wound, curing stomachache, diarrhea and antichloristic antispasmodic, antiseptic and infection preventing properties, and have also been used to reduce sweating and to stop bleeding, amarum, stomachicum, cholagolum and carminativum.3, 6-12 The Achillea genus has a wide distributional range,13 and the differences in oil composition may be affected by different environmental factors such as plant genetic type, seasonality, and developmental stage, because it is a chemically polymor-phic and perennial plant.14 Terpenoids (1,8-cineole, camphor, borneol, pinenes, artemisia ketone, santolina alcohol, farnesane, caryophyllene and its oxides, cubebene, germacrenes, eudesmol, α-bisabolol and oxides, farnesene, γ-gurjunene, γ-muurolene and chamazulene) are the principle components of Achillea essential oils.3 According to Nemeth’s (2005) studies, within the last 15 years, an average of 54 compounds have been identified in samples of different species. Among them, the largest numbers of components (149 compounds) were found in the oils of some Achillea species. 1, 8- Cineole, camphor, borneol, α- and β- pinenes are among the five most abundant monoterpene components. Among the monoterpenes, 1, 8-cineole is a major component in Achillea species.15-17 In some Achillea species, essential oil components (camphor and borneol) are next ranks.18-21 Other most detected components are α- and β- pinenes, especially in the A. millefolium species 22 Hofmann (1993) also reported that the monoterpenes belonging to the p-menthane, thujane and pinane are the most frequent components of the oils of the Achillea millefolium populations. Sesquiterpenes such as chamazulene, β-caryophyllene and oxide, eudesmol, α-bisabolol as well as its oxides and farnesene, are the most frequently constituents.3 Some researchers have reported the major constituent of several Achillea species as 1,8-cineole, camphor, piperitone and ascaridole in Turkey.15, 23-25 Chemical composition of the essential oils of five Achillea species from Turkey has already been investigated.6 The essential oils and hexane extracts of Achillea frarantissima and Achillea santolina from Egypt have been reported.26 Antimicrobial, antidiabetic, antioxidant, antitumor and spasmolytic effects of different Achillea species have been previously reported, 2, 10, 27-30 Essential oil composition of five Achillea biebersteinii from central Turkey, their antifungal, and insecticidal activity had also been investigated.31 Potential activity of the Achillea wilhelmsii leaves on bacteria and effects of the leaves essential oil and methanol extract of the A. wilhelmsii on the growth of the bacteria were investigated.32
In this experimental study, plant materials of Achillea species were collected from three different places in East-Azarbayjan province of Iran during the flowering period, in June at 2012. The location, the plant species, altitudes and oil yield are listed in Table 1. The collection area has the characteristics of terrestrial climate. The climate is characterized by warm to hot, temperate summer and freezing snowy winters. Aerial parts of Achillea samples were dried at room temperature. Flowers and leaves were separated after drying. All samples were hydro-distilled for essential oil by grossly pulverized powdered plant (40 g) using a Clevenger type apparatus for 3 h.
The essential oils were analyzed on a gas chromatograph mass spectrometer (Shimadzu-17A-QP505, Japan). The gas chromatography column was a super CP-Sil 5CB capillary column (50m × 0.32 mm ID, 0.25 µm film thickness). The column oven temperature was set at 70 °C for 1 min, increased to 100°C at a rate of 1.5°C/min, increased to 180 °C at a rate of 4 °C/min, and held at 180 °C for 1 min. Next, it was increased to 200 °C at a rate of 10 °C/min, increased to 250 °C at a rate of 2.5 °C/min, and held at 250 °C for 5 min. Injector and detector temperatures were 280 °C and 300 °C respectively. The gas chromatography mass analysis carried out with the same characteristics as used in gas chromatography. The ionization energy was 70 eV, with a scan time of 1 sec, and a mass range of 40-300 amu. Unknown essential oil was identified by comparing its gas chromatography retention time to that of known compounds, and its mass spectra to known compounds or published spectra.
Table 1: The altitudes of collection localities and essential oil yields of investigated Achillea specie
A total of 20 components of the essential oil of Achillea millefolium flowering aerial parts were identified (Table 2). The main constituents of A. millefolium were 1, 8-cineol (28.0%) and camphor (19.2%), followed by borneol (8.8%) and β-pinene (6.3%).
Table 2: Constituents identified from the essential oil of A. millefolium, A. biebersteinii and A. wilhelmsi aerial parts
A total of 16 components of the essential oil of A. biebersteinii flowering aerial parts were identified (Table 2). The principal compounds in A. biebersteinii oil were α-Terpinen (41.42%), 2-carene (13.96), m-cymene (13.41%), 1, 8-cineole (8.91%) and camphor (3.62%). Monoterpenoids represented 14 of the 16 compounds, corresponding to 90.63 of the whole oil, while 1 of 16 constituents were sesquiterpenoids (21.5% of the crude essential oil).
In the essential oils of A. wilhelmsii totally 23 components were identified, accounting for 92.1% of the total oil (Table 2). Carvacrol (29.2%), linalool (10/3%) and 1, 8- cineol (11.0%) were the 4 main constituents of A. wilhelmsii essential oil, followed by (E)- nerolidol (8.4%) and borneol (5.04%).
The aim of the present study was to determine the chemical composition of the essential oils of Achillea millefolium, A. biebersteinii and A. wilhelmsii from different locations of East-Azarbayjan in Iran.
The aired-dried aerial parts of plants yielded 0.35%, 45% and 0.56% oil, respectively. Chemical composition of essential oils of Achillea species was highly variable, which may be due to the differences in their chemical polymorphic structure and environmental conditions.
According to our data 1, 8- cineol (28.0%) and camphor (19.2%) were the main constituents of A. millefolium. Previous studies that have determined the chemical composition of A. millefolium essential oils also identified high levels of artemisia ketone (4.1% to 12.6%), camphor (6.1% to 24.5%), 1, 8-cineole (11.4% to 40.4%), linalool (0.9% to 9.5%) and borneol (3.2% to 9.2%).33-35 However, linalyl acetate was only found in trace amounts in other studies of A. millefolium essential oil; this difference might be due to the diversity of the plant sources or different essential oil hydrodistillation procedures. Moreover, earlier studies have shown that high quantities of monoterpene hydrocarbons and oxygen sesquiterpenes present in A. millefolium essential oils, ranging from 10.4% to 26.9%.35
The main constituents in A. biebersteinii oil showed some differences from those in the essential oils derived of A. biebersteinii from Turkey. For example, the main components of essential oil of A. biebersteinii were piperitone (31.06%), eucalyptol (10.98%) and camphor (12.46%).36, 37
In another study the main constituents of the oil of the plant collected from Mazandaran province were 1, 8-cineole (7.9%), camphor (6.5%), α-fenchene (5.7%) and santolian triene (5.1%) were four major compounds of the oil of this study.38
In the present study A. wilhelmsii, carvacrol (29.2%), linalool (10/3%) and 1, 8- cineol (11.0%) were the four main constituents of the essential oil. Nineteen components in the volatile oils of A. wilhelmsii from Kerman (Iran) were reported previously in which caryophyllene oxide (12.5%), camphor (9.0%), borneol (6.1%), linalool (5.5%), 1, 8- cineole (3.6%), chrysanthenyl acetate (2.8%) and carvacrol (2.0%) were the main ones.39 Comparison of two oils shows similarity in chemical composition, but with different percentages. Carvacrol (25.1%, linalool (11.0%), 1, 8- cineole(10.3%) and (E)-nerolidol (9.0%) were present in lower percentage in the oils of A. wilhelmsii from Kerman, while caryophyllene oxide the main oxygenated sesquiterpene in the oils of Kerman’s present in small amounts in oils of A. wilhelmsii from Kazeroon in Fars province. In another study the main constituents of the oil of the plant collected from Mazandaran province were camphor, borneol and 1, 8- cineole of which borneol and 1, 8- cineole were two major compounds of the oil of this study.39 1, 8- cineole, which consistutes 11.0% of the oil has also been reported as the major constituent of the oil of A. wilhelmsii from Egypt and Turkey and Mzandaran in Iran,39, 40 and some other Achillea species.21, 41-43 Camphor (2.6%) and (5.4%) were present as the main components of the oil of A. tenuifolia,44 and A. kellalensis from Iran respectively.
The essential oil constituents of flowering aerial parts of Achillea millefolium, A. biebersteinii and A. wilhelmsii (family Astreacea) collected from different locations of East-Azarbayjan in Iran, were studied. Among the three subjected species, A. wilhelmsii has the most abundant oil content (0.56%). In conclusion, our results demonstrate variations in the qualitative and quantitative composition in the oils obtained from the aerial parts of three distinct Achilleae species. These differences can probably be attributed to the genetic differences or different geographic or environmental conditions of the plant materials.
Conflict of interest
The authors declare that they have no conflict of interests.
The authors thank the Research Council of University of Tabriz for financial support.