ESSENTIAL OIL OF BOESENBERGIA STENOPHYLLA 485 FLAVOUR AND FRAGRANCE JOURNAL Flavour Fragr. J. 2003; 18: 485–486 Published online 1 October 2003 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/ffj.1227
The essential oils of Boesenbergia stenophylla R. M. Sm. as natural sources of methyl (E)-cinnamate Fasihuddin bin Ahmad1 and Ibrahim bin Jantan2* 1 2
Faculty of Resource Science and Technology, Universiti Malaysia Sarawak, 94300 Kota Samarahan, Sarawak, Malaysia Department of Pharmacy, Faculty of Allied Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia
Received 10 September 2002 Revised 15 January 2003 Accepted 21 January 2003
ABSTRACT: The rhizome and leaf oils of Boesenbergia stenophylla R. M. Sm. were analysed by gas chromatography on two columns of different polarity, retention indices and GC–MS. The oils were found to possess compositional similarities but quantitative differences in the concentration of each component. The oils are natural sources of methyl (E)-cinnamate, constituting 49.9–53.4% of the oils. They are also rich in sesquiterpenoids (39.8 and 40.3%, respectively) with δ -elemene, β -elemene, α -santalene, α -humulene, γ -muurolene, spathulenol, caryophyllene alcohol and kaur-16-ene as the main representatives. Copyright © 2003 John Wiley & Sons, Ltd. KEY WORDS: Boesenbergia stenophylla R. M. Sm.; Zingiberaceae; essential oil composition; methyl (E)cinnamate; δ -elemene; β -elemene; α -santalene
Introduction Boesenbergia stenophylla R. M. Sm. (Family Zingiberaceae) is a perennial rhizomatous herb that can be found in the kerangas and mixed dipterocarp forest floor of highland areas of Sarawak, Malaysia, especially Bario. It usually inhabits sandy loam soil which is high in moisture content. It grows in patches but luxuriant growth can be observed under a loose forest canopy.1 B. stenophylla, known locally as ‘jerangau merah’, is praised for its ethno-botanical importance among the various ethnic groups. Its decoction is believed to increase the libido, to protect against convulsions and to prevent intoxication. It is also commonly used for the preparation of tonics. A mixture of crushed rhizomes of B. stenophylla and Zingiber cassumunar is used as a poultice or lotion for rheumatic pains. The decoction of B. stenophylla rhizomes is also used as an antiseptic wash, for treating stomach-ache and to dissolve kidney stones (B. A. Fasihuddin, personal communication). To our knowledge no chemical studies on B. stenophylla have been reported. Another species of this plant, B. pandurata, has been studied extensively by many workers, resulting in the isolation of various
* Correspondence to: I. bin Jantan, Department of Pharmacy, Faculty of Allied Health Sciences, Universiti Kebangsaan Malaysia, 50300 Kuala Lumpur, Malaysia. E-mail:
[email protected] Contract/grant sponsor: Universiti Malaysia Sarawat; Contract/grant number: 246/2001[5]. Contract/grant sponsor: Universiti Kebangsaan Malaysia; Contract/grant number: NTGF/112/2001.
Copyright © 2003 John Wiley & Sons, Ltd.
flavonoids.2–4 The flavonoids were shown to exhibit anti-inflammatory and antibacterial properties.3,4 A study of the essential oils of B. pandurata has been reported by us.5 In this paper, we report on the chemical constituents of the rhizome and leaf oils of B. stenophylla.
Experimental Plant Material The fresh rhizomes and leaves of B. stenophylla were collected from the Bario Highlands, Sarawak, Malaysia, in November 2001. A voucher specimen was deposited at the Herbarium of Universiti Malaysia Sarawak, Sarawak.
Oil Isolation The plant materials were subjected to water distillation in a Clevenger-type apparatus for 8 h. The oily layers obtained were separated and dried over anhydrous magnesium sulphate. The yields were averaged over three experiments and calculated based on the dry weight of the plant materials.
Analysis of the Oils The oils were analysed on a Shimadzu GC 14A chromatograph equipped with a FID detector using a DB-5 capillary column (25 m × 0.25 mm, 0.25 µm film thickness).
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The operative parameters were: nitrogen as carrier gas at 50 cm/s, injector and detector temperatures were maintained at 250 °C. The column was programmed initially at 75 °C for 10 min, then 3 °C/min to 210 °C and held for 1 min. The oils were also examined using a DB-1 stationary phase column (25 m × 0.25 mm, 0.25 µm film thickness) programmed from 60 °C for 10 min, then 3 °C/min to 180 °C and held for 10 min. Peak areas and retention times were measured by electronic integration. The relative amounts of individual components are based on the peak areas obtained, without FID response factor correction. Temperature-programmed linear retention indices of the compounds were also determined relative to n-alkanes.6 The oils were also analysed by GC–MS with a Hewlett-Packard GC-MSD 5890 Series 2 mass spectrometer (70 eV direct inlet) on a BPX5 column (30 m × 0.25 mm, 0.25 µm film thickness) with similar conditions as described in the GC programs. The constituents were identified by comparison of their retention indices with literature values and their mass spectral data with those from the Wiley mass spectral database, and in some cases by co-chromatography on the different columns with authentic samples.7–9
Results and Discussion Water distillation of the fresh rhizomes and leaves of B. stenophylla yielded the following percentages of essential oils: rhizomes (3.39%) and leaves (1.63%) (calculated based on a dry weight basis), comparable to essential oil yield from the rhizomes of B. pandurata (2.42–3.30%) reported previously.5 The essential oil yield was high and may be considered satisfactory for commercial exploitation. The list of constituents identified in the oils is shown in order of elution on a DB-5 type column in Table 1. The results showed that the oils were qualitatively similar but with some variation in levels of the individual constituents. The gas chromatograms of the oils revealed the presence of at least 40 components, of which 34 were identified (Table 1). From analysis of the mass fragmentation patterns, the unidentified components were sesquitepene hydrocarbons and their oxygenated derivatives. The oils could be natural sources of methyl (E)-cinnamate (49.9– 53.4%) (Table 1). The oils were also rich in sesquiterpenoids which constituted more than 45% of the oils. The major representatives of sesquiterpenoids were δ -elemene (1.5–7.4%), β -elemene (2.0–2.9%), α -santalene (2.8– 3.1%), α -humulene (2.8–5.3%), spathulenol (2.6–5.6%) and kaur-16-ene (1.8–3.9%). The rhizome oil could be differentiated from the leaf oil by the presence of higher amounts of δ -elemene (7.4%) and γ -muurolene (5.1%), while the latter contained higher concentrations of α -humulene (5.3%) caryophyllene alcohol (3.1%) and α -calacorene (7.7%).
Copyright © 2003 John Wiley & Sons, Ltd.
Table 1. Chemical constituents of the essential oils of Boesenbergia stenophylla Compound
Content (%)
RI
Method of identification
960 979 1099 1166 1177 1188 1300 1341 1350 1377 1391 1419 1420 1432 1436 1440 1448 1456 1459 1478 1480 1486 1499 1505 1509 1510 1526 1555 1560 1565 1568 1578 1582 2034
a,b,c a,b,c a,b,c a,b,c a,b,c a,b,c a,b,c a,b a,b,c a,b,c a,b a,b,c a,b a,b a,b a,b,c a,b,c a,b,c a,b a,b a,b a,b a,b a,b a,b a,b a,b,c a,b a,b a,b,c a,b a,b a,b,c a,b
Rhizome Leaf Benzaldehyde β -Pinene Linalool Borneol Terpinen-4-ol α -Terpineol Methyl (Z)-cinnamate δ -Elemene α -Cubebene (E)-Methyl cinnamate β -Elemene β -Caryophyllene α -Santalene γ -Elemene α -trans-Bergamotene Aromadendrene epi-β -Santalene α -Humulene (E)-β -Farnesene γ -Muurolene Germacrene D β -Selinene α -Muurolene Germacrene A (E,E)-α -Farnesene β -Bisabolene δ -Cadinene Germacrene B β -Calacorene (E)-Nerolidol Caryophyllene alcohol Spathulenol Globulol Kaur-16-ene
0.3 0.1 t 0.4 t t t 7.4 0.1 53.4 2.9 1.1 3.1 0.5 1.2 0.4 0.7 2.8 0.7 5.1 1.4 0.7 0.2 0.1 1.3 0.2 1.7 2.1 0.7 t t 2.6 0.3 1.8
1.0 0.3 0.2 0.4 t 0.2 0.2 1.5 t 49.9 2.0 0.8 2.8 t 0.9 t t 5.3 0.6 0.5 0.9 0.4 0.3 t 1.1 0.2 0.2 0.2 7.7 0.3 3.1 5.6 1.1 3.9
Total
94.3
92.5
Percentages were calculated on the basis of results obtained on the DB-5 column; all relative response factors being taken as 1; RI, retention index; tentative identification for all compounds, except for c; a, mass fragmentation; b, retention index; c, co-chromatography with authentic sample; t, trace.
Acknowledgements—The authors are grateful to Universiti Malaysia Sarawak and Universiti Kebangsaan Malaysia for providing research grants (UNIMAS No. 246/2001[5] and UKM Grant NTGF/112/2001) and Abu Said Ahmad of the Forest Research Institute of Malaysia for running the GC–MS spectra.
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