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| ORIGINAL ARTICLE |
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| Year : 2012 | Volume
: 11
| Issue : 1 | Page : 49-52 |
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The lipid and volatile oil of the seed and aerial parts of Onopordum alexandrinum Boiss. growing in Egypt and their antioxidant activity
Walid El-Sayed Abd-Allah1, Hany M. Radwan1, Khaled A. Shams1, Shams I. Ismail1, Seham M. Ali2
1 Department of Phytochemistry, National Research Center, Cairo, Egypt
2 Department of Botany, Faculty of Science, Ain Shams University, Cairo, Egypt
| Date of Submission | 12-Oct-2011 |
| Date of Acceptance | 26-Feb-2012 |
| Date of Web Publication | 18-Jul-2014 |
Correspondence Address:
Walid El-Sayed Abd-Allah
Department of Phytochemistry, National Research Center, Tahrir St. Dokki, 12311 Cairo
Egypt
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.7123/01.EPJ.0000415230.8360.f1
Purpose
The study of the lipid of the seed and aerial parts of Onopordum alexandrinum Boiss., family Asteraceae, growing in Egypt led to the isolation and identification of the unsaponifiable and fatty acid fractions of both the seed and the aerial parts of the plant. Also, isolation of volatile oil of the seed and studying their antioxidant activity.
Subjects and methods
The constituents of the unsaponifiable fraction of the seed, aerial parts of the plant and volatile oil of the seeds were identified by Gas liquid chromatography (GLC) analysis. The radical scavenging effects of the tested extracts of both the seed and the aerial parts of the plant using DPPH free radicals.
Results
GLC analysis of the unsaponifiable fraction of the seeds indicated a mixture of hydrocarbons ranging from C13 to C28; cholesterol, campasterol, stigmasterol, and β-sitosterol were also present. GLC analysis of the fatty acid methyl esters of the seeds indicated the presence of eight fatty acids. Also, GLC analysis of the unsaponifiable fraction of the aerial parts of the plant indicated a mixture of hydrocarbons ranging from C17 to C28. Cholesterol, campasterol, stigmasterol, and β-sitosterol were also present. GLC analysis of the fatty acid methyl esters of the aerial parts indicated the presence of nine fatty acids. Sixteen compounds were identified by GLC analysis represented 77.97% of the total composition of the oil of the seeds.
Conclusion
The unsaponifiable fractions of both the seed and the aerial parts of the plant and volatile oil showed a strong antioxidant activity, whereas the fatty acid fractions showed a moderate antioxidant activity. Keywords: antioxidant activity, Asteraceae , fatty acids, Onopordum alexandrinum , unsaponifiable fraction, volatile oil
How to cite this article:
Abd-Allah WE, Radwan HM, Shams KA, Ismail SI, Ali SM. The lipid and volatile oil of the seed and aerial parts of Onopordum alexandrinum Boiss. growing in Egypt and their antioxidant activity. Egypt Pharmaceut J 2012;11:49-52 |
How to cite this URL:
Abd-Allah WE, Radwan HM, Shams KA, Ismail SI, Ali SM. The lipid and volatile oil of the seed and aerial parts of Onopordum alexandrinum Boiss. growing in Egypt and their antioxidant activity. Egypt Pharmaceut J [serial online] 2012 [cited 2023 Feb 9];11:49-52. Available from: http://www.epj.eg.net/text.asp?2012/11/1/49/136970 |
| Introduction | |  |
The family Asteraceae is one of the largest families of flowering plants, with approximately 1100 genera and 2500 species 1. In Egypt, there are 97 genera including 230 species 2. Onopordum is a genus of about 40 species. In Egypt, there are only two species of Onopordum: O. alexandrinum and O. ambiguum 2,3. A review of the literature indicated that several plants of the genus Onopordum have antimicrobial and antitumor activities 4. O. alexandrinum is used as an expectorant, for healing wounds, and as a treatment of skin cancers 5,6.
Preliminary phytochemical investigations of the seeds of O. alexandrinum growing in Egypt using standard procedures have shown that it contains terpenes, flavonoids, coumarins, sterols, and volatile oils.
There is very little information on the phytoconstituents of the seeds of O. alexandrinum. Therefore, in this work, the lipid and volatile oil of the seeds of the plant and the antioxidant activities of both the lipid and the volatile oil constituents are studied.
| Subjects and methods | | |
Plant material
O. alexandrinum Boiss. was collected from Bourg El-Arab near Alexandria in May 2010. The plant was identified by Dr M. El-Gebaly and Dr S. El-Kawashty, who are taxonomists at the National Research Centre (Cairo, Egypt) to whom the authors are very grateful. The seeds and aerial parts of the plant were air dried and ground into a fine powder. A voucher specimen was kept in the herbarium of National Research Center.
Reagent and solvent
6-Hydroxy-2, 5, 7, 8-tetramethylchroman-2-carboxylic acid (Trolox; Aldrich Chemical Co., Germany), 1,1-diphenyl-2-picrylhydrazyl (DPPH; Sigma Chemical Co., USA), and methanol (HPLC grade) were used.
Apparatus and techniques
Gas liquid chromatography (GLC, Hewellett HP-6890 series, USA) was carried out. GLC analyses were carried out under the following conditions.
For the unsaponifiable matter
Column: HP-1 (methyl siloxane) 30 m length/0.53×2.65 µm, temperature program: initial temperature 60°C, initial time 2 min, program rate 10°C/min, final temperature 280°C, final time 30 min, injection temperature 260°C, detector (FID), T=300°C, flow rate of carrier gas N2: 30 ml/min, H2: 35 ml/min, air: 30 ml/min.
For fatty acids
Methyl esters of fatty acids were analyzed on HP-6890 GC.
Column: HP-5 (phenyl methyl siloxane) 30 m length/0.32×2.25 µm, temperature program: initial temperature 60°C, initial time 2 min, program rate 8°C/min, final temperature 270°C, final time 10 min, injection temperature 270°C, detector (FID), T=300°C, flow rate of carrier gas N2: 30 ml/min, H2: 35 ml/min, air: 30 ml/min.
For the volatile oil
Column: HP-INNOWAX-polyethylene glycol, length: 30 m, diameter: 250 µm, film thickness: 0.15 µm. Oven temperature: initial temperature 70°C, initial time 2 min. Ramps: rate 3°C/min, final temperature 190°C, final time 5 min, injection temperature 250°C, detector (FID), T=260°C, flow rate of carrier gas N2: 33 ml/min, H2: 35 ml/min, air: 330 ml/min.
Preparation of the lipid matter of the seeds
Approximately 300 g of the air-dried powdered seeds of O. alexandrinum Boiss. were extracted with petroleum ether (40–60°C). The purified extract was evaporated and the residue (3.349 g) was dissolved in boiling acetone (100 ml) and cooled; however, no precipitate was found. The acetone-soluble fraction was saponified (N/2 alc. KOH) and the unsaponifiable matter (1.21 g) was separated. The fatty acid mixture released was extracted and methylated (methanol, 4.5% HCl). Samples of the isolated unsaponifiable fraction and the methyl esters of fatty acids were subjected to GLC analyses 7.
Preparation of the lipid matter of the aerial parts
Approximately 350 g of the air-dried powdered aerial parts of O. alexandrinum Boiss. were extracted with petroleum ether (40–60°C). The purified extract was evaporated and the residue (4.95 g) was dissolved in boiling acetone (100 ml) and cooled; however, no precipitate was found. The acetone-soluble fraction was saponified (N/2 alc. KOH) and the unsaponifiable matter (1.32 g) was separated. The fatty acid mixture released was extracted and methylated (methanol, 4.5% HCl). Samples of the isolated unsaponifiable fraction and the methyl esters of fatty acids were subjected to GLC analyses 7.
Preparation of the volatile oil
Approximately 300 g of the dried powdered seeds of O. alexandrinum were macerated with three-fold their weight with petroleum ether (40–60°C) at room temperature for 48 h. The maceration was repeated twice. The petroleum ether extract was evaporated and then subjected to water distillation for about 3 h until no more volatile oil could be distilled. The oil was extracted from the aqueous layer by shaking with ether, which was evaporated after dehydration over anhydrous sodium sulfate. A yellowish green oil was obtained (0.59 g). The volatile oil was subjected to GLC analysis, and the compounds were identified by comparison of their relative retention times with the available authentics 8.
Antioxidant activity
Determination of scavenging effect on DPPH radicals
The effect of the plant extracts on DPPH was studied using the modified method described by Chen and Ho 9. The decrease in the absorbance of the DPPH solution at 516 nm after the addition of the sample (plant materials) was measured in a glass cuvette. An aliquot of a 0.1 ml M. methanol solution of DPPH was mixed with the methanolic solution of the sample, so that the relative concentration of plant materials versus the stable radical in the cuvette was 0.13; then the solution with the tested sample was shaken vigorously. The absorbance was determined at the start and 30 min after being kept in the dark against a blank of methanol without DPPH. All tests were run in duplicate and averages were calculated 10. The antioxidative activities of these samples were compared with Trolox as follows:
where RSA is the radical scavenging activity.
| Results | | |
Unsaponifiable fraction of the seeds
GLC analysis for the unsaponifiable fraction of the seeds of O. alexandrinum indicated a mixture of hydrocarbons ranging from C13 to C28, in which C23 (45.39%) was the main hydrocarbon. Also, cholesterol, campasterol, stigmasterol, and β-sitosterol were present, in which stigmasterol was the main sterol (4.245%) [Table 1]. | Table 1: Gas liquid chromatography analysis of the unsaponifiable fraction of the seeds of Onopordum alexandrinum Boiss.
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Unsaponifiable fraction of the aerial parts
GLC analysis of the unsaponifiable fraction of the aerial parts of O. alexandrinum indicated a mixture of hydrocarbons ranging from C17 to C28, in which C23 (5.8%) was the main hydrocarbon. Also, cholesterol, campasterol, stigmasterol, and β-sitosterol were present, in which β-sitosterol was the main sterol (22.98%) [Table 2]. | Table 2: Gas liquid chromatography analysis of the unsaponifiable fraction of the aerial parts of Onopordum alexandrinum Boiss.
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Fatty acid fraction of the seeds
GLC analysis of the fatty acid methyl esters of the seed of the plant indicated that the presence of eight fatty acids represented 87.21% of the total acids, in which oleic acid C18(1) was the main acid (43.924%) as shown in [Table 3]. | Table 3: Gas liquid chromatography analysis of the fatty acid methyl esters of the seeds of Onopordum alexandrinum Boiss.
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Fatty acid fraction of the aerial parts
GLC analysis of the fatty acid methyl esters of the aerial parts of the plant indicated that the presence of nine fatty acids represented 88.97% of the total acids, in which stearic acid C18(0) was the main acid (31.14%) as shown in [Table 4]. | Table 4: Gas liquid chromatography analysis of the fatty acid methyl esters of the aerial parts of Onopordum alexandrinum Boiss.
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| Discussion | | |
GLC analysis of the unsaponifiable fraction of the seeds of O. alexandrinum indicated a mixture of hydrocarbons ranging from C13 to C28, in which C23 (45.39%) was the main hydrocarbon. Also, cholesterol, campasterol, stigmasterol, and β-sitosterol were present, in which stigmasterol was the main sterol (4.245%) [Table 1].
Also, GLC analysis of the unsaponifiable fraction of the aerial parts of the plant indicated a mixture of hydrocarbons in which C23 (5.8%) was the main hydrocarbon. Also, a mixture of sterol compounds was present in which β-sitosterol was the main sterol (22.98%), [Table 2]. Identification of the compounds was carried out by comparison of their retention time with the available reference compounds.
GLC analysis of the fatty acid methyl esters of the seed of the plant indicated that the presence of eight fatty acids represented 87.21% of the total acids, in which oleic acid (C18(1), 43.924%) and palmitic acid (C16, 20.44%) were the main acids [Table 3]. GLC analysis of the fatty acid methyl esters of the aerial parts of the plant indicated that the presence of nine fatty acids represented 88.97% of the total acids, in which stearic acid C18(0) was the main acid (31.14%) as shown in [Table 4].
The constituents of the volatile oil obtained from the seeds of O. alexandrinum were identified using GLC analysis. Sixteen compounds were identified, which represent 77.97% of the total composition of the oil, in which carvacrol (9.134%), δ-cadinene (12.086%), and trans-carveol were the main constituents [Table 5]. | Table 5: Constituents identified in the volatile oil of the seeds of Onopordum alexandrinum Boiss.
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The radical scavenging effects of the tested extracts of both the seed and the aerial parts of the plant using DPPH free radical were also determined [Table 6]. The unsaponifiable fractions of both the seed and the aerial parts of the plant and volatile oil showed a strong antioxidant activity, whereas the fatty acid fractions showed a moderate antioxidant activity.
| Conclusion | | |
The bioactive constituents of herb and seeds of O. alexandrinum were evaluated for their biological activity. The unsaponifiable fractions of both the seed and the aerial parts of the plant and the volatile oil showed a strong antioxidant activity, whereas the fatty acid fractions showed a moderate antioxidant activity. Growing awareness of the protective functions of thistles highlights the need to conserve and manage them sustainably. Thus, O. alexandrinum is a very promising medicinal plant and a good candidate for further detailed and specific phytochemical and pharmacological studies.
| Acknowledgements | | |
The authors are deeply indebted to Prof. Dr F.M. Hammouda for her kind help and continuous support.[10]
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]
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