Specific characteristics of essential oils of four Artemisia species from the Mongolian Trans-Altai Gobi

The essential oil compositions of four Artemisia species in Mongolian Trans-Altai Gobi were studied by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The oil from A.macrocephala Jacq and A.dracunculus Ledeb. were characterized by the presence of monoterpene hydrocarbons and oxygenated monoterpeneoids predominately. E-nerolidol (26.95%), methyleugenol (23.29%) and sabinene (13.21%) were found as main components in the essential oils of A.dracunculus. A.macrocephalla was characterized by the presence of chamazulene (13.8%), cineol (11.7%), myrcene (9.0%), germacrene-D (7.1%). A.anethifolia Web was characterized by the presence of fragrant compounds as camphor (26.05%), α-thujone (10.1%), borneol (5.1%). Davanone and davanone derivatives were also detected in the sample in amount of 7.7% in total. A.scoparia Waldst differed by domination of monoterpene hydrocarbons (78.9%) with (Z)β-ocimene (29.24%), α-pinene (15.19%), limonene (10.27%) and myrcene (9.61%).


INTRODUCTION
The genus of Artemisia (family Asteraceae) which contains many useful aromatic and medicinal plants, comprises of about 400 species found in the northern hemisphere [1].The genus Artemisia presents 103 species that are found wild all over the Mongolia [2,3].Artemisia popularly known as "sagebrush" or "wormwood" is a source of valuable drugs and essential oils.Because of medicinal importance and intricate chemical composition of several varieties and chemotypes, Artemisia continues to be subject of wide interest for chemists and taxonomists.The genus Artemisia produces a great number of terpenoid compounds in glandular trichomes which have been found to be biologically active [4].Currently, the pharmaceutical [5][6][7][8], food science [9,10], fragrance [9,11] and in perfumery [12], cosmetical industries [13] are intensively studying the terpenoids of Artemisia and their sesquiterpenoid lactones [14][15][16].The Artemisia species are rich in volatile oils that exhibit a wide spectrum of biological activity as antiinflammatory, antibacterial, antifungal, anti-oxidant, antiviral, allelopathic etc [17,18].A.macrocephala, A.scoparia are used as an antiseptic, anti-inflammatory, antihelmintic, tonic as well as for the treatment of stomachache and toothache in Mongolian traditional medicine [4,5,8].A literature survey revealed only a few reports on essential oil composition of A.macrocephala, A.scoparia and many researches for A.dracunculus is known Tarragon [19][20][21][22].
Tarragon possesses insecticide and radicalscavenging activities.Antifungal, antitumor and DNAdamaging effects were also reported for the essential oil of A.dracunculus [23].Worthy of mention is the use of the aromatic leaves of A.dracunculus in perfumery and range of food applications which include soups, causes, salad dressing and in the Tarragon vinegar [9,10,23,24].Previously, reported constituents of A.macrocephala were flavonoids, alkaloids, saponins and terpenes including α-pinine, β-pinine, limonene, p-cymene, borneol and 1,8-cineole in the essential oil of the plant.The oil also contains camphor propionic acid, acetic acid, enanthic acid and isovaleric acid.[21,22,25].Mohammad Shoaib et al., examined that the essential oil of A.macrocephala possesses acetylcholinesterase and butyrylcholinesterase inhibitory potential and revealed from the study beneficial applications of the oil in treatment of various neurodegenerative disorders including Alzeimer`s disease, Parkinson`s disease, ataxia and all other forms of dementia [25].

EXPERIMENTAL
Plant material: Aerial parts of A.scoparia, A.anethifolia, A.macrocephala and A.dracunculus were collected from wild growing plants in Mongolian Trans-Altai Gobi at full flowering and fruiting stage in July-September 2011-2013.The exact dates of each harvesting are showed in Table 1.A voucher specimen has been deposited in the Herbarium fund of the Institute of Botany of the Mongolian Academy of Sciences, Ulaanbaatar, Mongolia.Isolation of oil: Air-dried aerial parts (70-80 g) were subjected to a hydro distillation in Clevenger type apparatus for 3 h.The samples were yielded 0.43% (w/w) of A.scoparia oil, 0.75% of A.anethifolia oil, 0.23% of A.macrocephala oil and 0.56% of A.dracunculus oil.The oils were dried over anhydrous calcium chloride and stored in sealed vials at 4ºC before analysis.

Gas chromatography (GC) and gas chromatography and mass spectrometry (GC/MS): GC analysis was carried out on Hewlett Packard HP 5890II
Gas Chromatograph fitted with an fused silica DB-Wax column (30m×0.25mm×0.25µm);carrier gas nitrogen, linear velocity 38 ml/min, split ratio 30:1.The injector and detector temperature was 250ºC, column temperature was programmed from 80 to 200ºC at a rate 2ºC/min, 0.5 µl solutions of essential oil samples in dichloromethane (1%) were subjected to the injector.Quantitative data were obtained from an electronic integration of the flame ionization detector (FID) peak area.GC-MS analysis was performed on HP 5971A instrument with MS detector 5890II of the same company which was operated in EI mode (70eV).GC-MS fitted with a Supelcowax 10 column (60m×0.25mm×0.25µm);carrier gas helium, linear velocity 10 ml/min, split ratio 30:1.The injector and detector temperature was 250ºC and 280ºC, column temperature was programmed from 80 to 120ºC at a rate 3ºC/min.All GC condition and capillary column used were as described above but a carrier gas was helium.

Identification of components:
The separated components were identified by matching with massspectral library data and by comparison of Kovat's indices with those of authentic components and with published data [30][31][32][33][34].

RESULTS AND DISCUSSION
The essential oils were isolated from the aerial parts of four Artemisia species at full flowering and fruiting stage were obtained in 3 replications and taken means of the oil yields as shown in Table 1.Additionally the place and time of collection of the plant materials are given in Table 1.

Table 1 .
Essential oil yields of four Artemisia species

Table 1 .
[1,3,7,10]oil yields of four Artemisia species, % Furthermore chemical compositions of the essential oil from A.anethifolia in the Gobi were investigated firstly[1,3,7,10], which are dominated by monoterpenoids.Determining components as main from the Artemisia species are methyleugenol in A.dracunculus, aromatic alcohols and ketones in A.anethifolia, chamazulene in A.macrocephala possess high bioactivity properties and the essential oils could be effective supplements for medicine, food, perfumer industries.