Grammosciadium genus is belongs to the family Apiaceae (Umbellifereae). The family includes 97 genera and 402 species in the Flora of Turkey [1]. Grammosciadium was established by De Candolle as a new genus containing two species, G. daucoides DC. and G. meoides DC., in 1829 [2]. The members of genus Grammosciadium are distributed in Turkey and also in Transcaucasica, Iran and Armenia [1-5]. Generally, they occur in temperate or temperate cold pasture lands and are considered to be attractive animal feed. The genus occurs also in Iraq, G. platycarpum and grows naturally in the mountainous regions of the country. It is a perennial plant with a very strong fragrance [6].

Essential oils are valuable natural products used as raw materials in many fields such as perfumes, cosmetics, aromatherapy, and food industry [7]. There is an increasing attempt to screen plants for studying the biological activities of essential oils from chemical and pharmacological investigations to therapeutic aspects [8-13]. The essential oil of members of Grammosciadium genus, have antibacterial activity [14,15], free radical scavengers and antioxidant activity [4-16]. In vitro antibacterial and antioxidant activity of the essential oil and its two main components of G. scabridum Boiss growing wild in Iran, as well as the composition of its essential oil were studied [15].

The results of the essential oils of two Grammosciadium species will give some clues on the chemotaxonomic relationships of family and genus patterns. In the present study, we report the yield and chemical composition of the essential oil isolated from the aerial parts of G. platycarpum and G. macrodon. This is the first report on the essential oil composition of G. macrodon and for G. platycarpum from Turkey origin.

Plant materials

The plant samples were collected from their natural habitats and identified by Mehmet Yavuz Paksoy. G. platycarpum (voucher specimen no. 7998 G) was collected from Muş (Turkey), Malazgirt, Kaz lake surroundings, step, 1800 m, on 25 June 2012, G. macrodon (voucher specimen no. 7985) was collected from Van (Turkey), Bahcesaray, Karabel geçiti, 2400 m, on 29 May 2012. The voucher specimens were kept in FUH (Fırat University Herbarium).

Extraction of essential oils

Hundred grams of air-dried aerial parts of the plant materials were extracted to hydrodistillation using a Clevenger-type apparatus for 3 h for extraction of the essential oil.

Gas chromatography (GC) analysis

The essential oil was analyzed using HP 6890 GC equipped with and FID detector and an HP- 5 MS column (30 m x 0.25 mm i.d., film tickness 0.25 µm) capillary column was used. The column and analysis conditions were the same as in GC - MS. The percentage composition of the essential oils was computed from GC – FID peak areas without correction factors.

Gas chromatography/mass spectrometry (GC-MS)

The oils were analyzed by GC - MS, using a Hewlett Packard system. HP- Agilent 5973 N GC - MS system with 6890 GC in Plant Products and Biotechnology Res. Lab. (BUBAL) in Firat University. HP-5 MS column (30 m x 0.25 mm i.d., film thickness 0.25 µm) was used with helium as the carrier gas. Injector temperature was 250 ^oC, split flow was 1 ml/min. The GC oven temperature was kept at 70 ^oC for 2 min. and programmed to 150 ^oC at a rate of 10 ^oC/min and then kept constant at 150 ^oC for 15 min to 240 ^oC at a rate of 5 ^oC/min. Alkanes were used as reference points in the calculation of relative retention indices (RRI). MS were taken at 70 eV and a mass range of 35 - 425. Component identification was carried out using spectrometric electronic libraries (Wiley and Nist library).

The compounds identified in the oils of Grammosciadium sp. studied are listed in in elution order from the HP-5MS column. The hydro distillation of the aerial parts of G. platycarpum and G. macrodon yielded 0.2 % and 0.4 % of pale yellowish oils, respectively. The extracted essential oils were complex mixture of non-terpenes, monoterpenes and sesquiter-penes; 49 components were identified out of which 15 are common to both oils ().

In the essential oil of G. platycarpum, the monoterpene hydrocarbons made up the high contribution (ca. 65 %) limonene being the most abundant compound. In contrast, this fraction was reduced ca. 20 % in the essential oil of G. macrodon and caryophyllene oxide (15.9 %) was assigned as the main sesquiterpene.

In this study, twenty-seven components in the essential oil of G. platycarpum were identified. The most abundant constituents were limonene (28.4 %), β-pinene (16.1 %), β-selinene (15.9 %), δ-3-carene (11.2 %), α-farnesene (6.0 %) and p - cymene (4.7 %) (). In the oil of G. macrodon, thirty-seven components were characterized representing 94.4 % of the total oil, with caryophyllene oxide (15.9 %), germacrene - D (12.4 %), β-caryophyllene (11.5 %), δ-3-carene (10.1 %) and cyclohexane (4.6 %) as the main constituents (). Both oils revealed limonene (28.4 %, 3.5 %), β-pinene (16.1 %, 2.8 %), δ-3-arene (11.2 %, 10.1 %), p - cymene (4.7 %, 2.5 %) and spathulenol (2.7 %, 3.8 %) as the main and common constituents in both species essential oils respectively (). α-farnesene (6.0 %), undecane (2.3 %), 2,6,10 – dodecatrien-1 - ol, 3,7,11 - trimethyl (1.2 %) and 6 methyl – 5 – hepten – 2 - one (1.1 %) were another major components in the G. platycarpum oil but they were not detected in the G. macrodon oil. Germacrene D (12.4 %), cyclohexane (4.6 %), cis - calamenene (3.5 %), caryophyllene II (2.3 %), isolongifolene (1.7 %), dodeconoic acid (1.6 %), salvia - 4(14) – en – 1 - one (1.3 %), 1,4-methanazulene (1.2 %) and α-humulene (1.0 %) were only determined in the G. macrodon oil.

Regarding the quantitative terpenoid composition, higher amounts of monoterpenoids in comparison with sesquiterpenoids are present in the essential oil of fruit, while in the leaf essential oil, sesquiterpenoids are the main group in G. platycarpum [4] from Iran. In another report it is declared that, the monoterpenes made up the higher contribution in G. platycarpum fruit essential oil from Iran [18]. However, it is sometimes usual to have such variations in the composition of the essential oils of plants resulting from geographical differences, growing conditions and variations in climate.

A review of the chemical constituents of Grammosciadium showed that the phytochemical composition of the genus has been addressed by a few studies in the past. Sonboli et al [14] reported that the essential oil from the whole aerial parts of G. platycarpum consisted mainly of linalool (79.0 - 81.8 %) and limonene (5.8 - 10.0 %). Also, Sonboli et al [15] analyzed the volatile constituents of the aerial parts of G. scabridum. This oil was characterized by high amounts of δ-terpinene (73.5 %), p - cymene (14.2 %), and (E) -β- farnesene (5.3 %). Nickavar et al [18] reported that the major components of the hydrodistilled essential oils obtained from dried leaves and fruits of G. platycarpum were linalool (26.1 and 53.9 %), (E,E) -α- farnesene (24.1 and 20.4 %) and (Z) -β- santalol (10.6 and 10.9 %), respectively.

There are some differences between this study and the previous investigation on the essential oil of G. platycarpum. Based on the present study and that of Sonboli et al [14], limonene was found as the main constituent. Moreover, α-farnesene, the major compound of G. platycarpum was also reported as the predominant compound by Nickavar et al [18]. The major compound, limonene, present in both species’ essential oils has also been reported to exist in G. scabridum [19]. Some similarities were found in view of the major essential oil compounds within the same family (Apiaceae) patterns. In the essential oil of Artedia squamata,  α - pinene (57.8 %), camphene (9.0 %), β - myrcene (5.7 %), δ-3-carene (5.3 %) and limonene (5.3 %) were determined as the major constituents and also butanoic acid (37.1 %), caryophyllene oxide (13.4 %), germacrene D (10.0 %) and β - caryophyllene (5.4 %)  were determined as major compounds in the essential oil of Malabaila secacul [20]. The majority of some common compounds in the essential oils may supply some contributions to the chemotaxonomy of the family patterns.

There are some qualitative and quantitative differences between both plant essential oils and G. platycarpum from other countries. This study demonstrates the occurrence of limonene/β-pinene chemotype of G. platycarpum and caryophyllene oxide/germacrene D chemotype of G. macrodon in Anatolian Region of Turkey. Members of the genus Grammosciadium are among the most important aromatic plants and the essential oils of this genus have great commercial value.