Chemical Composition of the Essential Oil from Aerial Parts of Astragalus schahrudensis Bge. from Northeast of Iran

Transcription

1 Jeobp 12 (1) 2009 pp ISSN X Chemical Composition of the Essential Oil from Aerial Parts of Astragalus schahrudensis Bge. from Northeast of Iran Hashem Akhlaghi Department of Basic Sciences, Islamic Azad University, Sabzevar Branch, Sabzevar, Iran Received 15 April 2008; accepted in revised form 22 November 2008 Abstract: The essential oil obtained by hydrodistillation of the aerial parts of Astragalus schahrudensis Bge. endemic to Iran, was analysed by GC and GC-MS. The volatile oil isolated from the aerial parts oil of A. schahrudensis was dominated with higher amount of benzyl benzoate (54.4 %) alongwith the fifteen components comprising 94.3 % of the total oil detected. In the whole oil, a nonterpene hydrocarbon predominated over monoterpene and sesquiterpene hydrocarbons. Keywords: Astragalus schahrudensis Bge., Papilionaceae, essential oil composition, benzyl benzoate Introduction: The genus Astragalus (Papilionaceae) contains about 800 species of perennial and annual plants, most of which are endemic to Iran 1,2. Previous investigations on different species of the genus Astragalus have shown the presence of triterpenes 3-9 and antimicrobial activities In the present study, hydrodistilled volatile oil from crushed dry aerial parts of Astragalus schahrudensis Bge. from Khorasan province was investigated by GC and GC-MS. This appears to be the first detailed report on the chemical composition of the essential oil of aerial parts of A. schahrudensis Bge. from Northeast of Iran. Exprimental Plant material: Aerial parts of A. schahrudensis was collected during the flowering stage in May, 2006 from Yam valley in Khorasan province, Northeast of Iran, at an altitude of 1600 m. A voucher specimen has been deposited in herbarium of the Faculty of Agriculture, Islamic Azad University, Sabzevar, Iran. Volatile oil isolation: Air-dried aerial parts (100 g) were subjected to hydrodistillation using a Clevenger-type apparatus for 3 h to produce essential oil. After decanting and drying over anhydrous sodium sulfate, the yellowish colored oil was recovered in yield of 0.11 % (w/w). *Corresponding author (Hashem Akhlaghi) E- mail: < sh_akhlaghi2001@yahoo.com >

2 Hashem Akhlaghi et al. / Jeobp 12 (1) 2009 pp GC analysis: Analytical gas chromatography was carried out on a Shimadzu 15 A gas chromatograph equipped with split/splitless injector (250 C) and a flame ionization detector (250 C). N 2 was used as carrier gas with flow rate of 1 ml/min. The capillary column used was DB-5 (50 m 0.2 mm, film thickness 0.32 μm ). The column temperature was kept at 60 C for 3 min. and then heated to 220 C with a 5 C/min. rate and kept constant at 220 C for 5 min. The characteristics have been depicted in Table 1. GC-MS analysis: A Hewlett-Packard 5973 apparatus fitted with a HP-5 MS column (30 m 0.25 mm, film thickness 0.25 μm) was used. The column temperature was kept at 60 C for 3 min. and programmed to 220 C at a rate of 5 C/min. and kept constant at 220 C for 5 min. Helium was the carrier gas (1 ml/min.). MS were taken at 70 ev. The characteristics have been depicted in Table 1. Qualitative and quantitative analyses: Identification of the constituents of the oil was made by comparison of their mass spectral fragmentation pattern and retention indices (RI) relative to C 9 -C 21 n-alkanes with those given in the literature 17 and stored in a MS library (Wiley 275). Relative percentage amounts of the components were calculated from peak area using a Shimadzu C-R4A Chromatopac on the DB-5 column without the use of correction factor. Results and Discussion: In the present work the hydrodistilled volatile oil from the crushed dry aerial parts of A. schahrudensis Bge. (family Papilionaceae) from Khorasan province, Northeast of Iran was studied by GC and GC-MS. The air dried aerial parts of this perennial plant yielded 0.11 % (w/w) yellowish colored oil and the composition is given in Table 2. Fifteen components comprising (94.3 %) of the total oil were identified in the oil: two monoterpene hydrocarbons (4.8 %), two oxygenated monoterpenes (3.7 %), six sesquiterpene hydrocarbons (18.3 %), one oxygenated sesquiterpene (5.0 %), one aromatic ester (54.4 %), one diterpene (0.4 %) and two aliphatic ketones (7.7 %). It was characterized by high amount of benzyl benzoate (54.4 %), followed by δ-cadinene (7.4 %), α-humullene (5.0%) and γ-cadinene (2.9 %). As can be seen from the above information the aerial parts oil contained large amount of an aromatic ester (54.4 %) and sesquiterpenes (23.3 %). The oil composition of the flower, leaves and stems from A. schahrudensis 15 does not match with the results obtained from present investigation. In other hand comparing these results with previous report on aerial parts oil of A. microcephalus Willd. showed the dominance of nonterpene hydrocarbons including hexadecanoic acid (31.9 %), heneicosane (9.1 %), tridecanol (6.2 %) and benzyl benzoate (6.2 %) 16. Identification of chemical compositions in water-distilled oils obtained from flowers, stems and leaves of A. schahrudensis collected from sabzevar, province Khorasan (Iran) had been the subject of previous contributed study 15, where seventeen compounds representing 96.6 % of flower oil of the plant were identified. The major compounds were germacrene D (47.6 %) and germacrene B (17.8 %); the stem oil was characterized by higher amounts of β-selinene (29.4 %), δ-guaiene (21.7 %), α-guaiene (13.4 %), and α-

3 Hashem Akhlaghi et al. / Jeobp 12 (1) 2009 pp selinene (10.9 %) among the fourteen components comprising 94.6 % of the total oil detected. The leaf oil was found to be composed of higher amounts of α-pinene (33.8 %), bornyl acetate (14.2 %), limonene (12.2 %) and α-fenchyl acetate (10.0 %) among the eighteen components comprising 97.3 % of the total oil detected. The flower and stem oils of A. schahrudensis consisted mainly of sesquiterpenes, while in leaf oil monoterpenes predominated over sesquiterpenes. Also in other report from the genus Astragalus the hydrodistilled oil from the aerial parts of A. microcephalus Willd. was analyzed via a combination of GC and GC-MS. The major constituents were hexadecanoic acid (31.9 %), heneicosane (9.1 %), α-cadinene (7.7 %), tridecanol (6.2 %) and benzyl benzoate (6.2 %) 16. Aknowledgements: I am grateful to Dr. V. Mozaffarian (research Institute of Forests and Rangelands, Tehran, Iran) for botanical identification and I would like to thank Dr. Richard Laursen, Boston University, for reviewing this manuscript and for his comments. References 1. Astragalus schahrudensis Bge. : Boissier. (1872). Flora Orientalis, vol. 2, p Mozaffarian V. (1996). A Dictionary of Iranian Plant Names. Farhang Moaser, Tehran. 3. Bedir, E., Calis, I., Dunbar, C., Sharan, R., Buolamwini, J.K., Khan, I.A. (2001). Two novel cycloartane-type triterpene glycosides from the roots of Astragalus prusianus., Tetrahedron. 57: Mamedova, R.P., Agzamova, M.A., Isaev, M.I. (2001). Triterpene glycosides of Astragalus and their genins. LXIII. Chemical transformation of cycloartanes. iv. Partial synthesis of trojanoside A., Chem. Nat. Compd. 37: Kucherbaev, K.D., Uteniyazov, K.K., Kachala, V.V., Saatov, Z., Shashkov, A.S. (2002). Triterpene glycosides from plants of the Astragalus genus. Structure of cyclounifolioside A from Astragalus unifoliolatus., Chem. Nat. Compd. 38: Mamedova, R.P., Agzamova, M.A., Isaev, M.I. (2002). Triterpene glycosides of Astragalus and their genins. LXV. Cycloartane and lanostane triterpenoids of Astragalus orbiculatus., Chem. Nat. Compd. 38: Mamedova, R.P., Agzamova, M.A., Isaev, M.I. (2003). Triterpene glycosides of Astragalus and their genins. LXVIII. Cycloorbigenin C, a new cycloartane genin., Chem. Nat. Compd. 39: Krasteva, L., Nikolov, S., Kaloga, M., Mayer, G. (2006). Triterpenoid saponins from Astragalus corniculatus. Z. Naturforsch. B, Chem. Sci.. 61 (9): Calis, I., Yuruker, A., Tasdemir, D., Wright, A.D., Sticher, O., Luo, Y.D., Pezzuto, J.M. (1997). Cycloartane triterpene glycosides from the roots of Astragalus melanophrurius., Planta Medica. 63 (2): Pistelli, L., Bertoli, A., Lepori, E., Morelli, L., Panizzi, L. (2002). Antimicrobial and antifungal activity of crude extracts and isolated saponins from Astragalus verrucosus., Fitoterapia. 73(4): Tan, B.K.H., Vanitha, J. (2004). Immunomodulatory and antimicrobial effects of some traditional Chinese medicinal herbs: A review., Current Medicinal Chem.

4 Hashem Akhlaghi et al. / Jeobp 12 (1) 2009 pp (11): Yan, Q.J., Jiang, Z.Q., Yang, S.Q., Deng, W., Han, L.J. (2005). A novel homodimeric lectin from Astragalus mongholicus with antifungal activity. Archives Biochem., Biophysics. 442(1): Jassbi, A.R., Zamanizadehnajari, S., Azar, P.A., Tahara, S. (2002). Antibacterial diterpenoids from Astragalus brachystachys., Z. Naturforsch. C, Biosci.. 57(11-12): Abbas, F., Zayed, R. (2005). Bioactive saponins from Astragalus suberi L. growing in Yemen., Z. Naturforsch. C, Biosciences. 60(11-12): Akhlaghi, H., Rustaiyan, A., Larijani, K., Shafaghat, A., Masnabadi, N., Masoudi, S. (2007). Chemical composition of the essential oil from flower, stem and leaves of Astragalus schahrudensis Bge. from Iran. J. Essent. Oil Res. 19: Rezaee, M.B., Jaimand, K., Karimi, M. (2006 ). Chemical constituents of the essential oil from Astragalus microcephalus Willd., J. Essent. Oil Res. 18: Adams, R.P. (2007). Identification of Essential Oil Components by Gas Chromatography/Mass Spectrometry 4 th Edithion, Allured Pub. Corp., Carol Stream, IL., USA. Table 1. Conditions of GC and GC-MS analysis Conditions of GC Column type/dimentions Fscc a : DB-5 / (50m 0.2mm, film thickness 0.32 μm) Carrier gas/flow-rate(ml/min.) N2/1 Temperature programming 60 C for 3 min. ramping to 220 C with a 5 C/min. rate and remaining constant for 5 min. in isothermal mode. Split ratio(ml/min) 1:50 Injector temperature( C) 250 Detector temperature( C) 250 Injection volume(μl) 0.2 Conditions of interface Interface type Membrane separator Interface temperature( C) 290 Conditions of MS 5972 selective detector Applied ionization energy (ev) 70 Ion source EI b Mode Full scan Mass transfer line temperature( C) 290 Scan velocity (s/scan) 0.2 a Fscc: Fused silica capillary column b EI: Electron impact (ionization)

5 Hashem Akhlaghi et al. / Jeobp 12 (1) 2009 pp Table 2. Percentage composition of the aerial parts oil of Astragalus schahrudensis Bge. No. Compound KI 1 (%) 1 α-pinene β-pinene ,8-Cineol Borneol α-gurjunene β-caryophyllene α-humulene α-muurolene γ-cadinene δ-cadinene α-cadinol Pentadecanone Benzyl benzoate Neophytadiene ,10,14-Trimethyl-2-pentadecanone Total percentage The compounds in this table have been arranged according to retention indices on HP-5MS capillary column