In Russian scientific medicine there are official plants from the Thymus genus: Thymus serpyllum L. and Thymus vulgaris L., which are used as expectorant means. The Thymus vulgaris L. grows in the Mediterranean countries. The main area of a Thymus serpyllum L. is the European part of Russia, but its resources are strongly exhausted. Now in the area of the Central Chernozem region the thyme is rarely spread, but along with it there grows about 7–8 close types in the territory of the specified areas: a Thymus marschallianus L., a Thymus pulegioides L., a Thymus calcareus L. and Thymus pallasianus L.
As a rule during preparation of raw materials of a thyme suppliers don’t distinguish types therefore there can be other types of raw materials along with a thyme and instead of it, widespread in this region and their different combinations. However, the species of a thyme widespread in the midland of the European part of Russia belong to various sections and subsections and naturally differ by morphological features and by chemical structure, according to the contents and qualitative structure of essential oil, as one of the main classes of biologically active agents of plants of a Thymus genus.
The thyme herb contains essential oil which includes aromatic terpenes: thymol; cymophenol; monoterpenes, sesquiterpenes, the content of which strongly varies depending on a place of growth, a habitat, height above a sea level, phases of development of a plant, etc.
There are more than 8 chemotypes of essential oil of Thymus genus plants, one of them has prevailing components such as thymol and cymophenol, while the other has in α-terpyneol, the third has geraniol, etc.
Thus, it was interesting to study a qualitative and quantitative composition of essential oil of a Thymus pallasianus L. belonged to the flora of the Midland of Russia.
Materials and methods. The object of research was the dry crushed herb of a Thymus pallasianus L. collected in the period of mass flowering in 2012 in the Voronezh region (area of Liski town).
For receiving and quantitative definition of essential oil a hinge plate of dry raw materials of a Thymus pallasianus L. (20 g) was placed in a flask, filled in 300 ml of water, closed with a stopper with the refrigerator and the receiver and brought to boiling. Distillation time from the boiling moment is 2 hours. After cooling the volume of essential oil in the receiver was determined.
For the analysis of essential oil 0,5–5,0 g of the crushed dried-up Thymus pallasianus L. herb was placed into «Agilent» vial for 20 ml, added the internal standard (tridecane), at the rate of 50 mkg on a hinge plate, then added 10 ml of cleared water , fastened a cover with the refrigerator with air cooling and placed in a small sandy bath with adjustable heating and heated within 2 hours. In the process of distillation flying substances were adsorbed on an inner surface of the return refrigerator. The adsorbed substances after cooling of system washed away 3 ml of especially pure pentane into dry vial for 10 ml. The washout was concentrated by a purge (100 ml/min.) especially pure nitrogen up to the residual volume of extract 10 mkl which was completely selected with a chromatographic syringe. A further concoction of test was carried out in the syringe up to the capacity of 2 mkl.
The test input into a chromatographic column was carried out in the splitless mode, i.e. without stream division that allows to enter test without loss on division and it increases sensitivity of a chromatographic method.
The research of a component composition of essential oil was conducted with a method of a gas-liquid chromatography on the Agilent Technology 6890 N chromatograph with the mass and spectrometer detector 5973 N. Analysis conditions: the chromatographic column capillary DV-5, length of a column is 30 m, internal diameter is 0,25 mm; gas carrier – helium, speed of gas carrier is 1 ml/min.; test volume – 2 mkl, the speed of test input is 1,2 ml/min. within 0,2 minutes; temperature of the thermostat is 50 °C with programming 3°/mines to 220 °C; temperature of the detector and evaporator of 250 °C.
The components of essential oil were identified as a result of comparison of mass spectrums of the substances entering into studied essential oil, received in the course of a chromatography with library data of mass spectrums of NISTO5 and WILEY 2007 with total of ranges more than 470000 in a combination with programs for AMDIS and NIST identification.
The quantitative maintenance of components was counted with the use of a method of the internal standard.
Results and discussion. At the first stage we carried out a quantitative definition of essential oil by a volume method at the basis of which distillation with water vapor lies.
As a result it was established that the content of essential oil in a Thymus pallasianus L. herb fluctuates from 0,22 to 0,58 %. Essential oil represents easily mobile liquid of yellowish color with a pleasant specific smell.
The analysis of essential oil of a Thymus pallasianus L. herb showed on the chromatogram not less than 40 substances from which 29 were identified (Figure, Table)
Composition of essential oil of a Thymus pallasianus L.
|
Number |
Keeping time |
Name of a Component |
Maintenance of Components in samples, % |
|
1 |
6,92 |
1,3,8-p-menthatrien |
0,08 |
|
2 |
7,29 |
α-terpynen |
0,04 |
|
3 |
7,39 |
p-cimen |
0,04 |
|
4 |
7,64 |
Limonene |
0,37 |
|
5 |
9,33 |
Terpynolen |
0,05 |
|
6 |
9,58 |
Linalool |
0,43 |
|
7 |
10,57 |
Camfora |
0,86 |
|
8 |
13,23 |
α-terpyneol |
37,56 |
|
9 |
13,59 |
Trans-carveol |
0,88 |
|
10 |
13,95 |
Carvon |
1,14 |
|
11 |
15,41 |
Bornylacetate |
0,46 |
|
12 |
15,92 |
Thymol |
0,18 |
|
13 |
17,44 |
α-terpynilacetate |
1,67 |
|
14 |
17,67 |
Trans-detsenal |
0,13 |
|
15 |
17,80 |
Nerilacetate |
0,08 |
|
16 |
18,36 |
Geranilacetate |
0,15 |
|
17 |
18,71 |
β-burbonen |
0,77 |
|
18 |
18,91 |
β-elemen |
0,18 |
|
19 |
19,95 |
β-cubeben |
0,09 |
|
20 |
20,35 |
β-caryophillen |
0,12 |
|
21 |
21,50 |
Germakren D |
1,82 |
|
22 |
21,85 |
Bicyclogermakren |
0,14 |
|
23 |
22,33 |
α-farnesen |
0,30 |
|
24 |
23,14 |
Burbonanol |
0,22 |
|
25 |
24,00 |
Nerolydol |
4,75 |
|
26 |
24,32 |
Salvial-4(14)-en-1-on |
0,23 |
|
27 |
29,81 |
Hecsahydrofarnesilacetone |
0,14 |
|
28 |
31,57 |
Palmitic acid |
0,16 |
|
29 |
32,35 |
Farnesol |
0,12 |
The scheme of chromatogram chromato-mass and spectral analysis of essential oil of a Thymus pallasianus L. herb
The dominating component of the studied essential oil is α-terpyneol, its content makes 37,56 %, and also nerolydol (4,75 %) against a small quantity of thymol (0,18 %) and absence of cymophenol.
Thus, essential oil of a Thymus pallasianus L. herb of flora of the Midland of Russia was investigated. The maintenance of connections of thymol typical of a Thymus genus in studied essential oil is insignificant (0,18 %). The main components of oil are α-terpyneol (37,56 %) and nerolydol (4,75 %). As a result it is possible to claim that the studied sample of essential oil of a Thymus pallasianus L. belongs to a chemotype terpyneol. There were 29 connections identified, basic of which are α-terpyneol (37,56 %), and nerolydol (4,75 %).
The work is submitted to the International Scientific Conference «Current problems of education», Greece, October, 15-24, 2013, came to the editorial office оn 19.09.2013.