Terpenoids of Blumea oxyodonta Essential Oil

Blumea oxyodonta DC. (Asteraceae) is a diffuse herb that grows up to 30 cm long. Many stems branch out from the base; they are spreading, procumbent, or ascending, villous white, with long glandular hairs. The leaves are radical and clustered at the base, densely silky white, and have glandular hairs on both surfaces. B. oxyodonta is grown as a weed near moist places of the Ghats and distributed throughout India, Myanmar, Pakistan, Indochina, China, Vietnam, and the Philippines [[1] ]. In the traditional system of medicine the decoction of the roots is used for treatment of impotency and spermatorrhea [[2] ]. The aim of this study was to explore the terpenoid profile of B. oxyodonta. To the best of the author’s knowledge, B. oxyodonta has not been the subject of any research, and this is the first scientific report on the terpenoid constituents of its essential oil.

Sixty-one compounds were characterized and identified according to their mass spectra and their relative retention indices determined on a nonpolar stationary phase capillary column, comprising 98.8% of the total oil constituents. The identified compounds are listed in Table 1 in elution order from the BP-1 column, along with the percentage composition of each component and its RI. The main constituents were identified as β-caryophyllene (23.5%), 2,5-dimethoxy-p-cymene (14.7%), and germacrene D (13.2%). The other minor constituents were 1-epi-cubenol (6.8%), guai-3,10(14)-dien-11-ol (5.8%), and epi-α-cadinol (5.4%). The oil was found to be rich in sesquiterpene hydrocarbons (45.8%), followed by oxygenated sesquiterpenes (25.8%), phenyl derivative constituents (16.9%), oxygenated monoterpenes (6.3%), monoterpene hydrocarbons (4.0%), and others (long-chain oxygenated hydrocarbons and aromatic hydrocarbons (< 0.1%).

Composition of Essential Oil from Blumea oxyodonta, %

Compound	RI	%	Compound	RI	%
α-Thujene	913	1.1	Methyl salicylate	1156	Tr.
α-Pinene	918	0.7	γ-Terpineol	1161	0.3
β-Pinene	949	0.2	Verbenone	1175	0.2
Dehydro-1,8-cineole	957	0.1	trans-Pulegol	1184	Tr.
(3Z)-Hexenyl acetate	965	Tr.	β-Cyclocitral	1190	Tr.
α-Phellandrene	972	0.5	Cuminaldehyde	1207	Tr.
δ-3-Carene	980	Tr.	Carvacrol methyl ether	1216	Tr.
α-Terpinene	984	0.4	Carvotanacetone	1219	0.5
o-Cymene	986	0.3	(E),(E)-2,4-Decadienol	1306	0.3
1,8-Cineole	994	0.7	6,7-Dimethyl-1,2,3,5,8,8a-hexahydronapththalene	1328	Tr.
(Z)-β-Ocimene	1002	0.2	Eugenol	1352	0.4
(E)-β-Ocimene	1013	0.1	α-Cubebene	1374	0.2
γ-Terpinene	1024	0.2	(Z)-β-Damascenone	1392	0.4
n-Octanol	1032	Tr.	α-Copaene	1405	1.2
Methyl benzoate	1044	Tr.	β-Bourbonene	1413	0.2
m-Cymene	1049	Tr.	β-Cubebene	1419	0.1
Terpinolene	1055	0.3	(E)-β-Damascone	1429	0.5
Dehydrosabinaketone	1064	3.6	2,5-Dimethoxy-p-cymene	1444	14.7
Chrysanthenone	1078	0.4	β-Caryophyllene	1454	23.5
Borneol	1133	0.5	α-trans-Bergamotene	1476	0.3
α-Humulene	1491	3.7	1-epi-Cubenol	1679	6.8
(E)-β-Farnesene	1499	0.1	epi-α-Cadinol	1691	5.4
γ-Muurolene	1515	0.2	Cubenol	1695	1.1
Germacrene D	1523	13.2	α-Muurolol	1704	2.6
epi-Cubebol	1537	1.1	Guai-3,10(14)-dien-11-ol	1720	5.8
α-Zingiberene	1544	1.2	5-neo-Cedranol	1724	1.9
Cubebol	1559	0.2	Benzyl benzoate	1795	0.6
δ-Cadinene	1571	0.3	Monoterpene hydrocarbon		4.0
β-Sesquiphellandrene	1573	1.2	Oxygenated monoterpenes		6.3
Cadina-1,4-diene	1580	0.3	Sesquiterpene hydrocarbons		45.8
α-Calacorene	1583	0.1	Oxygenated sesquiterpenes		25.8
ar-Turmerol	1619	0.2	Phenyl derivatives		16.9
Caryophyllene oxide	1625	0.5	Others		Tr.
Guaiol	1634	0.2	Total identified		98.8

RI: retention indices relative to C8-C25n-alkanes on BP-1, Tr.: trace (< 0.1%).

Plant Material and Isolation Procedure. The aerial parts of B. oxyodonta were collected in February, 2014 from Belagavi (N 15.88668; E 74.52353), Karnataka, India at an elevation of approximately 800 m. The plant was identified at ICMR-National Institute of Traditional Medicine (NITM), Belagavi (voucher specimen No. RMRC-1306). The fresh aerial parts were subjected to hydrodistillation using a Clevenger type apparatus for 3 h. The oil was trapped by adding n-hexane and dried over anhydrous Na2SO4 and kept in a sealed vial at -4°C until analysis. The yield of oil was 0.02%.

Analysis and Identification of the Oil Components. The oil was analyzed using a Varian 450 (TG-5, 30 m × 0.25 mm i.d., 0.25 μm film thickness) gas chromatograph under the experimental conditions reported earlier [[3] -[5] ]. The oven temperature was programmed from 60-230°C at 3°C/min, using nitrogen as carrier gas. The injector temperature was 230°C, and the detector (FID) temperature was 240°C. GC-MS utilized a Thermo Scientific Trace Ultra GC interfaced with a Thermo Scientific ITQ 1100 mass spectrometer fitted with a BP-1 (SGE Analytical Science) fused silica capillary column (30 m × 0.25 mm; 0.25 μm film thickness). The oven temperature range was 60-230°C at 3°C /min using helium as carrier gas at 1.0 mL/min. The injector temperature was 230°C, and the injection volume 0.1 μL in n-hexane, with a split ratio of 1:50. MS were taken at 70 eV with a mass range of m/z 40-450 [[6] -[8] ]. Identification of constituents was done on the basis of retention index (RI, determined with reference to the homologous series of n-alkanes C8-C25, under identical experimental conditions), MS library search (NIST 08 MS Library (Version 2.0 f; Thermo Fisher Scientific Austria), Wiley MS 9th edition (Thermo Fisher Scientific Austria), and by comparing with the MS literature data [[9] ].

Published in Khimiya Prirodnykh Soedinenii, No. 2, March-April, 2018, pp. 319-320.

Acknowledgment

The author is grateful to the Indian Council of Medical Research (ICMR), New Delhi, India for providing the necessary facilities and thankful to Mahesh B. Wagharwadi, Multi Tasking Staff (MTS), Department of Phytochemistry, NITM, Belagavi for processing of the plant material and extraction of the oil.

References Citations

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• 2 Quattrocchi U, CRC World Dictionary of Medicinal and Poisonous Plants: Common Names, Scientific Names, Eponyms, Synonyms, and Etymology, 2012, Boca Raton, FL, CRC press, 606
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By R. K. Joshi