Constituents of the Volatile Oil of Inula oculus-christi L. from Iran

Journal of Essential Oil Research: JEOR, Nov/Dec 2006 by Javidnia, Katayoun, Banani, Armita, Miri, Ramin, Kamalinejad, Mohammad, Javidnia, Azita

Abstract

The essential oil of Inula oculus-christi was examined by GC and GC/MS. Sixty compounds were identified representing 90.6% of the oil. The major components were pentacosane (13.7%), palmitic acid (13.6%), dill apiole (11.4%), methyl eugenol (9.6%) and viridiflorol (5.7%).

Key Word Index

Inula oculus-christi, Compositae, pentacosane, palmitic acid, dill apiole.

Introduction

The genus Inula belongs to the Compositae family and comprises 14 species growing wild in Iran (1). It is distributed mainly in the Alborz Mountains in Iran. The oils of I. cuspidata and I. viscosa showed antifungal activity against pathogenic fungi (2,3). A petroleum ether extract of the roots of I. racemosa was found to lower plasma insulin and glucose and also show negative chronotropic and negative inotropic activity on the frog heart (4). Two sesquiterpene lactones have previously been isolated from the aerial parts of I. oculus-christi (5). In the present work we report the constituents of the oil of the aerial parts of I. oculus-christi L. from Iran, which has not been reported previously.

Experimental

Plant material and isolation procedure: Aerial parts of the plant were collected in June 2002 from the Alborz Mountains at the time of flowering. The plant was identified by the Department of Botany of the Medical Sciences University of Shaheed Beheshti. A specimen (Herbarium No. 1127) has been deposited in the Herbarium of the Faculty of Pharmacy, The Medical Sciences University of Shaheed Beheshti. The aerial parts were air-dried at ambient temperature in the shade and hydrodistilled by using a Clevenger-type apparatus for 4 h. The yield of oil was 0.07%(w/w) and the color of the oil was yellow. It was dissolved in hexane (Merck), dried over anhydrous sodium sulfate and stored at 4°-6°C.

Identification of the oil components: Analytical gas chromatography (GC) was carried out using a Varian GC 3600 FID chromatograph with DB-5 (methylphenylsiloxane 25 m x 0.25 mm, 0.25 µm film thickness), carrier gas N^sub 2^ with split ratio 1:20 and flame ionization detector. Temperature programming was performed from 60°-240°C at 3°C/min, with injector and detector temperatures, 240°C and 260°C, respectively. GC/MS was performed on a crossed linked 5% methylphenylsiloxane (HP-5, 30 m x 0.25 mm, 0.25 µm film thickness) with He as the carrier gas and split ratio 1:20 and quadropole mass spectrometer (Helwett- Packard 6890) operating at 70 eV ionization energy. EIMS spectra were obtained in scan mode in m/e range 35-400 amu. The chromatographic conditions were as above. Retention indices were determined by using retention times of n-alkanes injected after the oil under the same chromatographic conditions. The retention indices for all the components were determined according to the Van Den Dool method using n-alkanes as standard (6). The compounds were identified by comparison of retention indices (RRI, HP-5) with those reported in the literature and by comparison of their mass spectra with those held in Wiley library of mass spectra or with the published mass spectra (7-9). Quantitative data were obtained from electronic integration of peak areas without the use of correction factors.

Results and Discussion

The oil of I. oculus-christi was examined by GC and GC/MS. The list of the compounds identified in the oil can be seen in Table I. Sixty compounds were identified, representing 90.6% of the total oil in which the major components were pentacosane (13.7%), palmitic acid (13.6%), dill apiole (11.4%), methyl eugenol (9.6%) and viridiflorol (5.7%). The main components of the oil had an aliphatic structure.

The main components of the oil of I. viscosa were borneol, bornyl acetate and isobornyl acetate, which were not present in the oil of I. oculus-christi (10). In other studies, the main components of the oil were borneol and bornyl acetate in I. graveolens and alantolactone and isoalantolactone in I. helenium (11,12). Inula verbascifolia ssp. methanea from Greece is comprised mainly of T-cadinol and (Z)-nuciferol, while methyl salicylate and cis-chrysanthenol were found as major constituents of the oil of I. verbascifolia ssp. parnassica (13). Inula racemosa posessed heptadeca-1,8,11,14-tetraene (aplotaxene) as the main compound while α-phellandrene (11.0-26.2%), β-phellandrene (up to 30.7%) and p-cymene (up to 53.8%) were the major compounds of I. crithmoides from Greece, Malta and Spain (14,15).

Acknowledgment

This work was supported by a grant from the Research Council of the Medical Sciences University of Shiraz.

References

1. K.H. Rechinger, Flora Iranica, Compositae IV. Vol. 145, edits., K.H. Rechinger and I.C. Hedge, op 89, Akademlsche Druck und Verlagsanstalt, Graz (1982).

2. P. Chauhan and V.K. Saxena, Antifungal activity of essential oil of leaves of Inula cuspidate. Indian J. Pharm. Sci., 47, 160-161 (1985).

3. C. Cafarchia, N. De Laurentis, M.A. Millano, V. Losacco and V. Puccini, Antifungal activity of essential oils from leaves and flowers of Inula viscosa (Asteraceae) by Apulian region. Parassitologia, 44, 153-156 (2002).