Introduction
============

The genus *Trigonella* L. with nearly 135 species belongs to the tribe Trifolieae and family of Fabaceae. Most of the species are distributed in the dry regions around the east Mediterranean, western Asia, south Europe, and north and South Africa, with only one species being present in South Australia. They are herbaceous and annual or perennial plants with pinnately trifoliate leaves, often emitting an odor; and like other grain legumes, are important in food and medicine production. This genus is represented by ca. 33 species in Iran, 12 of which are endemic ([@R1], [@R2]). *Trigonella torbatjamensis* was recently introduced as an endemic plant in Iran ([@R1]). Various species of the genus *Trigonella* have important medical and culinary aspects. Among these, *Trigonella foenum-graecum* L. is commonly grown as a vegetable. It has some medicinal uses. Externally the drug acts as an emollient and internally reduces blood sugar, but the mechanism of its action is unclear. Additionally, a lipid-lowering effect, which is attributed to the saponin fraction, has been proven. Its approved uses by Commition E are loss of appetite and inflammation of the skin. It has been used in Indian medicine as an anti-fever and for treatment of vomiting, anorexia, bronchitis, and colitis. In Chinese medicine, the drug is used to treat impotence and hernia ([@R3]). It has been used in Indian folk medicine as an antipyretic, diuretic, and supportive, and for treatment of dropsy, heart disease, chronic cough, and enlargement of the spleen and the liver ([@R3]). There are few reports on the essential oil content of members of this genus ([@R4]-[@R10]). The essential oil of *T. torbatejamensis* Ranjbar, a species of the genus in the eastern part of Iran, has not been studied previously. We report here the composition of the essential oil of *T. torbatejamensis* which is an endemic species growing wild in Iran, for the first time.

Materials and Methods
=====================

Aerial parts of *T. torbatejamensis* were collected during the flowering stage from a region between Saghar Cheshmeh and Garmab Olia, (35 ° 45 ′ N, 61 °15′ E), 400 -- 500 m., east of Saleh-Abad, near Torbat-e Jam, Razavi Khorasan province, north-east of Iran in May 2012. The species were identified by Mr MR Joharchi from Herbarium of Ferdowsi University of Mashhad (FUMH) where voucher specimen of the plant was deposited (No.34445).

The air-dried and powdered aerial parts (200 g) of *T. torbatejamensis* were subjected to hydro-distillation using a Clevenger-type apparatus for 3 hr. After decanting and drying over anhydrous sodium sulfate, the slightly yellow-colored oil was recovered in yield of 0.1 % (v/w) and stored in tightly closed dark vials at -20°C prior to GC-FID and GC/MS analysis.

Gas- chromatography and gas-chromato-graphy-mass spectrometry
-------------------------------------------------------------

### Gas chromatography

The GC analysis was performed using a Varian CP-3800 equipped with FID detector, fused- silica column (CP-Sil 8CB, 50 m × 0.25 mm, film thickness 0.12 µm). The operating conditions were: oven temperature 50°C (5 min), 50°C--250°C (3°C /min), 250°C (10 min); injector temperature 260°C, split ratio 1:5, with the carrier gas N2 (2 ml/min); detector temperature 280°C.

Gas chromatography-mass spectrometry
------------------------------------

The GC-MS analyses were performed using an Agilent 5975 apparatus with HP-5ms column (30 m x 0.25 mm id, 0.25 µm film thickness) interfaced with a quadruple mass detector and a computer equipped with Wiley 7 n.l library; oven temperature, 50°C (5 min), 50°C--250°C (3°C /min), 250°C (10 min); injector temperature 250°C; injection volume, 0.1 µl; split ration, 1:50; carrier gas was Helium at 1.1 ml min; ionization potential, 70 eV; ionization current, 150 µA; ion source temperature, 250°C; mass range, 35-465 mui.

The constituents of the oil were identified by calculation of their retention indices under programmed temperature conditions for n-alkanes (C8-C20) and the oil on a CP-Sil 8CB column. The individual compounds were identified by comparison of their mass spectra and retention indices (RI) with those of authentic samples and those being given in literatures ([@R11]). Quantification of the relative amount of the individual components was performed according to the area percentage method without consideration of calibration factor.

Results
=======

GC and GC--MS analyses showed that 98.5% of the essential oil was comprised of a total of 40 compounds (Figure [1](#F1){ref-type="fig"} and Table [1](#T1){ref-type="table"}). Considering the quantitative results, the pattern of the main grouped components in essential oil was as follows: sesquiterpene hydrocarbons (70.2%), oxygenated sesquitepenes (16.5%), oxygenated monoterpenes (3.5%) and monoterpene hydrocarbons (0.5%). Germacrene --D (33.0%), bicyclogermacrene (26.0%), and viridiflorol (5.3%) were the main components of the essential oils obtained from the aerial parts of *T. torbatejamensis*.

Discussion
==========

Mazza, *et al* has reported over 50 volatile compounds in *T. foenum- graecum* ([@R4]). Another study revealed the presence of the volatile component palmidrol (28.72%), an antiviral, anti-inflammatory and non-steroidal analgesic, was a major bioactive constituent ([@R5]).

In this study, headspace dynamic GC-MS claimed the dominance of limonene (82.30%), d-carvone (12.97%) and *n*-caproaldehyde (1.87%), which are reported for the first time in the seeds of *T. foenumgraecum*. Mazza, *et al* reported prominent presence of carbonyl compounds in headspace analysis of this species ([@R6]).

The first investigation on compounds of oil obtained from Iranian *Trigonella* species dates back to 2004, when Ahmadiani *et al* examined the composition of the oil of fresh aerial parts of *T. foenum- graecum* L. collected from Kalateh, Ebrahimshah, 25 km from north of Boujnord, North Kohrasan Province ([@R7]). The yield of that oil was 0.3 % and had nine components representing 98.5 % of all compounds. Main components of this oil were δ- cadinene (27.6 %), α-cadinol (12.1 %), γ- eudesmol (11.2 %) and α- bisabolol (10.5 %). In a recent study on the same species, aerial parts of the plant were collected from Sari, Mazandaran Province of Iran. Forty components were identified and the main compounds of that oil were α -bisabolol (2.3%), γ- cadinene (1.8%) and α -- cadinol (1.7%) ([@R8]).

In 2009, the chemical composition of the volatile oil obtained from the leaves of *T. disperma* Bornm., an endemic widespread species of the genus *Trigonella* in the western part of Iran, was examined by Ranjbar *et al*. The oil had 18 compounds representing 87.1% of all compounds. Main components of that oil were pentacosane (27.3%), spathulenol (17.3%), and hexahydroxyfarnesyl acetone (6.7%) ([@R9]).

Recently, the essential oil from *T. monantha* C. A. Mey., subsp. *Monantha*, has been studied ([@R10]). The aerial parts of the plant were harvested from Karaj (Alborz Province). Thirty-eight compounds were identified in the oil of this taxon, representing 88.8% of its composition. The main compounds were dibutyl phthalate (10.3%), hexanal (9.5%), and nonanal (6.6%).

Conclusion
==========

The essential oil of aerial parts of *T. torbatjamensis* Ranjbar is consisted of forty components with sesquiterpene hydrocarbons being the main grouped components.

The authors would like to thank Mr Mohamadreza Joharchi from Department of Botany, Research Center for Plant Science, Ferdowsi University of Mashhad, Mashhad, Iran for his kindly assistance in finding and identification of the plant.

![Gas chromatogram of essential oil of the aerial parts of *T. torbatjamensis*](IJBMS-17-537_F1){#F1}

###### 

Percentage of the composition of the essential oil of aerial parts of *Trigonella torbatjamensis* in comparison with other *Trigonella species*

  No.      Compound                     RI[\*](#T1F1){ref-type="table-fn"}   Percentage   
  -------- ---------------------------- ------------------------------------ ------------ --------------------------
  1        α- pinene                    957                                  0.3          
  2        sabinene                     993                                  0.1          
  3        *n*-decane                   1020                                 4.6          
  4        limonene                     1049                                 0.1          14.6 (A~1~); 82.3 (A~2~)
  5        1,8-cineole                  1052                                 0.1          1.2 (E)
  6        α-thujone                    1123                                 0.3          
  7        borneol                      1182                                 0.2          1.8 (E)
  8        terpinene-4-ol               1191                                 0.7          
  9        α-terpineol                  1204                                 0.2          
  10       *n*-dodecane                 1209                                 0.8          
  11       carvone                      1257                                 1.8          9.9 (A~1~); 13.0 (A~2~)
  12       bornylacetate                1295                                 0.2          
  13       δ-elemene                    1344                                 0.5          
  14       α-copaene                    1380                                 0.3          
  15       β-bourbonene                 1388                                 1.1          
  16       β-elemene                    1395                                 0.8          
  17       *n*-tetradecane              1399                                 0.3          
  18       α-gurjunene                  1412                                 0.1          
  19       β-caryophyllene              1422                                 4.0          
  20       β-copaene                    1431                                 0.4          
  21       aromadendrene                1441                                 0.2          
  22       *cis*-muurola -3,5 - diene   1446                                 0.2          
  23       allo-aromadendrene           1462                                 2.2          
  **24**   **germacrene -D**            **1482**                             **33.0**     
  25       *trans*-β-ionone             1486                                 0.8          
  **26**   **bicyclogermacrene**        **1496**                             **26.0**     
  27       γ-cadinene                   1511                                 0.3          1.8 (C)
  28       δ-cadinene                   1520                                 1.1          27.6 (B)
  29       palustrol                    1564                                 0.4          
  30       spathulenol                  1575                                 4.6          17.8 (D)
  31       caryophyllene oxide          1580                                 1.8          7.9 (D)
  **32**   **viridiflorol**             **1587**                             **5.3**      
  33       ledol                        1597                                 1.6          
  34       unknown                      1631                                 1.1          
  35       *tau*-muurolol               1634                                 0.6          
  36       α-cadinol                    1646                                 1.3          1.7 (C)
  37       valeranone                   1663                                 0.9          
  38       heptadecane                  1680                                 0.4          
  39       mintsulfide                  1722                                 0.5          
  40       octadecane                   1774                                 0.4          
                                        **Major grouped compounds**                       
                                        Monoterpene hydrocarbons             0.5          
                                        Oxygenated monoterpenes              3.5          
                                        Sespuiterpene hydrocarbons           70.2         
                                        Oxygented sesquiterpenes             16.5         
                                        Miscellaneous compounds              7.8          
                                        Total identified                     98.5         

RI= The retention Kovats indices that were determined on CP-Sil 8CB capillary column

A~1~, Essential oil of *T. foenum-graceum* (Seed) by GC-MS ([@R5]); A~2~, Essential oil of *T. foenum-graceum* (seed) by head space GC-MS ([@R5]); B, Essential oil of *T. foenum-graceum* (aerial parts) ([@R7]); C, Essential oil of *T. foenum-graceum* (aerial parts) ([@R8]); D, Essential oil of *T. disperma* (aerial parts) ([@R9]); E, Essential oil of *T. monantha* (aerial parts) ([@R10])
