Chemical Composition of the Essential Oils for Anthemis melampodina from North Saudi Arabia

The chemical composition of essential oil of Anthemsmela mpodinais determined by GC/ MS. The oil was obtained by hydro-distillation and SPME extraction methodsIn the SPME method, a total of 41 constituents were identified monoterpene hydrocarbons (88.89%) were the main class of compounds detected in the SPME method with β-pinene (35.29%), trans-ocimene(23.96%) and terpinolene(15.78%) being detected as the main constituents. On the otherhand, hydrodistilled oil was rich in oxygenated sesquiterpene(31.22%).


INTRODUCTION
Anthemis(belonging to the Astraceae family)is a genus of 210species offlowering plants.Anthemis plants are known to growwidely in Europe, south western Asia, northern and north eastern Africa and southern Arabia.The arabic names for this plant include Qahwiyan,Rebyan and Arbiyar 1 .In Saudi Arabia, the genus Anthemis is represented by 17 species distributed in the central, eastern and northern regions 2 .examples include A. pseudocotula, A. bornmuelleri,A.cotula.A. odontostephena and A. melampodina 3 .In folk medicine Anthemis species are frequently used for the treatment of various ailments such as digestive problems, insomnia and toothache.Moreover, several studies also showed that different Anthemis species exhibited antiflammatory, antioxidant, antibacterial, antiproliferative and antispasmodic properties 4-8 .Most Anthemisspecies are economically important, due to their use in pharmaceutics, cosmetics and food flavoring [9][10][11][12][13] .Furthermore, chemical investigations on Anthemisspecies revealed that the genus is dominated by sesquiterpene lactones, flavonoids and polyacetylenes [14][15][16][17][18][19][20] .Anethimsmelampodina is anannual, greyish-tomentose, herb with ascending branches from near the base.The flowers are whiteyellow in color.This plant is known to grow widely in northern region ofSaudi Arabia including Hail 21 .
In a continuation of an extensive work aimed at the investigation of the volatile constituents of aromatic plants from Saudi Arabia, the current investigation was designed to investigate the chemical composition of the essential oil A. melampodina obtained by two different extraction methods, the Solid Phase Micro-Extraction and hydro-distillation methods and compare the current findings with those obtained from other locations of the world.

EXPERIMENTAL Plant Material
Aerial parts of A. melampodinawere collected during the full flowering stageMarch 2012) from Hart Alrha -south Tabuk.The identity of the plant species was confirmed by Dr Jacob Thomas from the Herbarium Division, College of Science, King Saud University, Riyadh, KSA.A voucher specimenAnthps-PNU-013was kept in the Chemistry Department, College of Science, Princess NouraBint Abdel Rhman University, Riyadh, Saudi.The plant material was dried at room temperature until constant weight was obtained.

Hydro-distillation of plant material
Air dried flowering parts (150 g) were coarsely powdered and then hydro-distilled using a Clevenger apparatus for 3 h.The extraction was repeated twice and the obtained oils were pooled separately, dried over anhydrous sodium sulfate (Na 2 SO 4 ) and stored at 4ºC in amber glass vials until analysis.

Solid Phase Micro Extraction of the volatile oils (SPME)
The Solid Phase Micro Extraction experiments were performed using SPME fiber assembly (Polydimethylsilocane/Divenylbenzene, PDMS/DVB; d f 65 mm partially crossed-linked phase, fiber length 1 cm) and assemblies for manual sampling (Supelco, Bellefonte, PA, USA).Before measurements, the fiber was conditioned according to the producer's recommendations.About 0.1 mg of freshly powdered flowerswas introduced into 4.0 mL amber glass vials, tightly capped with PTFEcoated septa, and SPME extraction was performed for 2.0 min at room temperature.Desorption of the analytes was carried out at 240ºC for 60 s.Each sample was repeated twice.

GC-MS and GC-FID analysis
About 1 µl aliquot of each oil sample, diluted to 5 µl in GC grade n-hexane, was subjected to GC/MS analysis.The GC/MS analysis was performed using Varian Chrompack CP-3800 GC/ MS/MS-200 (Saturn, Netherlands) equipped with DP-5 (5% diphenyl, 95% dimethyl polysiloxane) GC capillary column (30 m × 0.25 mm i.d., 0.25 µm film thicknesses), with helium as a carrier gas (flow rate 0.9 mL/min).The actual temperature in MS source was 180ºC and the ionization voltage was 70 eV.The column temperature was kept at 60ºC for 1 min (isothermal), and programmed to 246ºC at a rate of 3ºC/min, and kept constant at 246ºC for 3 minutes (isothermal).A hydrocarbon mixture of n-alkanes (C 8 -C 20 ) was analyzed separately by GC/MS under the same chromatographic conditions using the same DP-5 column.
For the quantitative analysis (% area), a Hewlett-Packard HP-8590 gas chromatograph equipped with a split-splitless injector (split ratio 1:50) and an FID detector was used.The column was an optima-5 (5% diphenyl, 95% dimethyl polysiloxan) fused silica capillary column (30 m × 0.25 mm, 0.25 film thickness).The temperature of the oven was increased at a rate of 10ºC/min from 60ºC to 250ºC and then held constant at 250ºC for 5 min.Thetemperatures of the injector and detector were maintained at 250ºC and 300ºC, respectively.The relative peak areas of the oil components were measured and then used to calculate the concentration of the detected compounds.Each sample was analyzed twice.

Identification of the components
The components of the essential oils obtained from the SPME and hydro-distilled flowering parts of the plant were identified using the built in libraries (Nist Co and Wiley Co, USA) and by comparing their calculated retention indices relative to (C 8 -C 20 ) n-alkanes literature values measured with columns of identical polarity (Adams, 2001), or with authentic samples.The compounds, áand â-pinenes, p-cymene, limonene, linalool (Fluka, Buchs, Switzerland) and sabinene hydrate (Sigma-Aldrich, Buchs, Switzerland) were used as reference substances in GC/MS analysis.GC-grade hexane and analytical reagent grade anhydrous Na 2 SO 4 were purchased from Scharlau (Barcelona, Spain) and UCB (Bruxelles, Belgium).
Previous studies on the essential oil of A. melampodinacollected in Egypt(1989) revealed to the isolation ofSesquiterpene lactones ,Sterols, flavonoid 22 .Again in Egypt (2002 ) The essential oil of the A. melampodina was characterized by the presence of a high percentage of monoterpene hydrocarbons (49.94%) while asesquiterpene hydrocarbons and oxygenated sesquiterpenes reported only the yield (0.03%) 7.41% and 11.43% of the oil while .In addition the essential oil of A.
Hence, the objective of the present study was undertaken to identify the chemical composition oil of Anthemismelampodina. plant collected from Tabouk.

Fig. 1 :Fig. 2 :
Fig. 1: Variation in the % composition of the essential oil of A. melampodinafrom Saudi origin obtained by SPME method.