Chemical constituents in the essential oil of the endemic plant Cotula cinerea（Del.）from the southwest of Algeria

Mohammed Djellouli，Houcine Benmehdi，Siham Mammeri，Abdellah Moussaoui，Laid Ziane，Noureddine HamidiLaboratory of Valorization of Vegetal Resource and Food Security in Semiarid Areas，South West of Algeria，University of B´echar，B´echar，Algeria

2Laboratory of Chemistry，Department of Chemistry，University of B´echar，B´echar，Algeria

Chemical constituents in the essential oil of the endemic plant Cotula cinerea（Del.）from the southwest of Algeria

Mohammed Djellouli1*，Houcine Benmehdi2，Siham Mammeri1，Abdellah Moussaoui1，Laid Ziane2，Noureddine Hamidi2
1Laboratory of Valorization of Vegetal Resource and Food Security in Semiarid Areas，South West of Algeria，University of B´echar，B´echar，Algeria

2Laboratory of Chemistry，Department of Chemistry，University of B´echar，B´echar，Algeria

ARTICLE INFO

Article history：

Accepted 19 Jun 2015

Available online 12 Aug 2015

Essential oil

Gas chromatography-mass spectrometry analysis

Cotula cinerea

Asteraceae

Sahara plants

Objective：To extract and identify the main constituents of the essential oil of Cotula cinerea（Del.）（Asteraceae family）from southwest of Algeria.

Methods：The essential oils obtained by hydrodistillation，from the aerial parts of the endemic plant Cotula cinerea which was collected in the region of Sahara from southwest of Algeria，were analyzed by gas chromatography-mass spectrometry.

Results：A total of 33 compounds were identified representing 98.66%of the oil.The main compounds were（E）-citral（24.01%），limonene epoxide cis-（18.26%），thymol methyl ether（15.04%），carvacrol（15.03%），trans-carveol（13.79%），carvone（3.06%）and trans-piperitol（2.54%）.

Conclusions：The main constituents in essential oil of the aerial part of the plant from southwest of Algeria were different from that collected from southeast of Algeria or in Morocco.

Original articlehttp://dx.doi.org/10.1016/j.apjtb.2015.06.007

1.Introduction

Because of their therapeutic properties，medicinal plants used in traditional medicine are one of the most interesting fields for the discovery of new drugs for the treatment of discharged diseases［1，2］.

No one can deny or retract that the beneficial effects of Saharan plants guide us to explore the essential oils secreted from endemic plants that were found in the B´echar region（southwest of Algeria）.Cotula cinerea（Del.）（C.cinerea）from Asteraceaes（Compositae）family［3］，is one of these endemic species and also the object of our study（Figure 1）.

The genus Cotula comprising 80 species is widespread in the southern hemisphere and is represented by three species in Algeria among which is our plant C.cinerea［4］.

The species C.cinerea，with synonym of Brocchia cinerea［5］，is a small woolly whitish plant，with thick leaf divided intheir upper part to a 3-5 obtuse teeth，stems are 10-40 cm，slept then raised；capitulum from 6 to 10 mm in diameter，woolly involucres with a tubular flower，and brown buds which would become golden yellow［2-6］.

The phytochemical screening of C.cinerea revealed the presence of flavonoids，tannins，alkaloids，saponins，terpenoids，steroids，and cardenolides［2］.These compounds are known to exhibitawiderangeofbiologicaleffectsincluding antibacterial and antioxidant activities.These data could justify the traditional use of this plant［7］.

This plant is usually known as“Guertofa”among the local people in Northern Sahara and is commonly used in traditional medicine in the southwest of Algeria，for the treatment of several diseases like colic，cough，diarrhea，headache，and digestive disorders.All parts of the plant are used in different forms（maceration，decoction，infusion or inhalation），according to the treated diseases［2］.

The aim of this work is to extract and identify the main constituents of the essential oil obtained from the aerial part（leaves and stem）of C.cinerea，collected in the Southwestern Algeria.

2.Materials and methods

2.1.Plant materials

The aerial parts（leaves and stems）of C.cinerea，were collected in February and March，2011，in the mountains and desert of Lahmar City（30 km far away from B´echar State），in southwest of Algeria and southeast of Morocco.The plants were identified and a voucher specimen was deposited at the herbarium of the Valorization of Resource and Food Security in Semiarid Areas Laboratory，South West of Algeria，University of B´echar.

2.2.Extraction of essential oil

The aerial parts（1 kg）were washed，sorted and dried for one month at room temperature in the shade and then were finely pulverized by using a mill blade.Clevenger-type apparatus was used for extraction，and hydrodistillation was performed for 6 h. The essential oil was dried with magnesium sulfate，then weighed and stored under refrigeration at 4-6°C in dark glass tubes for further use.

2.3.Analysis by gas chromatography-mass spectrometry（GC-MS）

Essential oils were analyzed by GC-MS（a Perkin Elmer Clarus 600 GC-MS system coupled with a Perkin Elmer Clarus 600C MS）.Helium（1 mL/min）was used as a carrier gas.The initial temperature was 60°C（2 min），then was increased to 200°C at rate of 5°C/min，and remained at 200°C for 5 min，and then was continued to increase to 250°C at rate of 10°C/min，with a final stage of 10 min at 250°C.The essential oils were placed in a glass capillary column（60 m×0.25 mm×0.25μm）filled with Rtx-5MS，and the oven temperature was programmed from 50°C to 250°C at a 5°C/min dynamic rate，and remained for 15 min at 250°C.

2.4.Identification of essential oil composition

Identification of components was performed by comparing their relative retention index（RI）determined with the reference of a homologous series of n-alkanes（C8to C24）［8-13］.The fragmentation patterns of the mass spectra were compared withtheWILEYandNIST05libraries.Thelinear temperature-programmed RIs of all the constituents were calculated based on the GC through the interpolation between bracketing n-alkanes as follow:

where Z was the number of carbon atoms in the smaller nalkane，and tR（i），tR（Z）and tR（Z+1）were the retention time of the desired compound，the smaller n-alkane and the larger n-alkane，respectively［14］.

3.Results

The yield of the greenest essential oil extracted by hydrodistillation from aerial parts of C.cinerea was 0.282%（v/w）. The results of GC-MS analysis showed the identification of 33constituents representing 98.66%of the total oil composition.As shown in Table 1，the major compounds were（E）-citral（24.01%），limonene epoxide cis-（18.26%），thymol methyl ether（15.04%），carvacrol（15.03%），trans-carveol（13.79%），carvone（3.06%）andtrans-piperitol（2.54%）（Figure2）.Theoil composition was dominated by the presence of oxygenated monoterpenes（95.40%）followed by monoterpene hydrocarbons（2.17%），oxygenated sesquiterpenes（0.68%）and sesquiterpene hydrocarbons（0.41%）.

Table 1 Chemical composition of C.cinerea essential oils.

4.Discussion

The essential oils from the aerial part of the species C.cinerea have been studied and described in the literature by several groups because of their interesting biological properties and varying bioactive compounds.Studies from El Bouzidi et al. and Kasrati et al.described trans-thujone（41.4%），cis-verbenyl acetate（24.7%），1，8-cineole（8.2%）and camphor（5.5%）as the major components of the plants collected in Morocco［15，16］，whileAtefetal.described3-car`ene（30.99%），thujone（21.73%），santolina triene（18.58%）and camphor（6.21%）from the oil obtained from a specimen collected in the Oued Souf Sahara in southeast of Algeria［17］.These essential oils haveverydifferentcompositionsfromtheessentialoil extracted from the aerial parts of C.cinerea presented in this study，with the major compounds of（E）-citral（24.01%），limoneneepoxidecis-（18.26%），thymolmethylether（15.04%），carvacrol（15.03%），trans-carveol（13.79%），carvone（3.06%）and trans-piperitol（2.54%）.These qualitative and quantitative differences in the chemical composition of essential oils could be attributed to several factors such as geographical location，the climatic effects，harvest season，nature of the soil，age of the plant parts（young or adult），the state of used plant materials（dried or fresh），the part of the plant used，time of collection and chemotype［18-20］.The oxygenated monoterpenes were found to be the major group in essential oil of C.cinerea，constituting 95.40%，and reported to be responsible for the antimicrobial activity of several essential oils［21，22］.This activity can justify the use of this plant in traditional medicine by the local people of Northern Sahara.

In conclusion，the essential oil of the aerial parts of C.cinerea was analyzed by GC-MS.（E）-citral，limonene epoxide cis-，thymol methyl ether，carvacrol，trans-carveol，carvone and trans-piperitol were the major constituents of the oil comprising 24.01%，18.26%，15.04%，15.03%，13.79%，3.06%and 2.54%，respectively，of the total compounds present.

The main constituents of the aerial part essential oil of the plant from southwest of Algeria were different from that collected from southeast of Algeria or in Morocco.These data present the existence of different chemotypes for this species［23］.

Conflict of interest statement

We declare that we have no conflict of interest.

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8 May 2015

Mohammed Djellouli，Laboratory of Valorization of Vegetal Resource and Food Security in Semiarid Areas，South West of Algeria，University of B´echar，Algeria.

E-mail:amine_841@hotmail.com

Peer review under responsibility of Hainan Medical University.

in revised form 18 May，2nd revised form 5 Jun 2015