Composition of the Essential Oil from the Leaves of Podachaenium eminens (Lag.) Sch. Bip.

Journal of Essential Oil Research: JEOR, Jul/Aug 2004 by Ciccio, Jose F, Soto, Victor H

Abstract

The composition of the leaf oil of Podachaenium eminens (Lag.) Sch. Bip. from Costa Rica was analyzed by capillary GC/MS. Seventy-three compounds were identified corresponding to about 88% of the oil. The mayor components were (E)-nerolidol (46.7%) and [alpha]-pinene (14.9%).

Key Word Index

Podachaenium eminens, Asteraceae, essential oil composition, (E)-nerolidol, [alpha]-pinene.

Plant Name

Podachaenium eminens (Lag.) Sch. Bip., Asteraceae, tribe Heliantheae, subtribe Verbesininae.

Source

Leaves of Podachaenium eminens from Costa Rica, were collected in San Pedro de Montes de Oca (San Jose) in an ecological life zone called Premontane Moist Forest (1), in April 1998. A voucher specimen was deposited in the Herbarium of the University of Costa Rica at the School of Biology (USJ 68593).

Plant Part

Fresh leaves of P. eminens were subjected to hydrodistillation for 2 h using a modified Clevenger-type apparatus. The distilled oil was collected and dried over anhydrous sodium sulfate and stored in a freezer (0�-10�C). The yellowish-green oil yield was 0.1-0.2% (v/w).

Plant Distribution

Podachaenium eminens is a shrub or a small tree of moist evergreen premontane-montane forests (ca. 1000-2500 m elevation) and ranges from Mexico to Costa Rica. This plant is called 'tora' or 'ton blanca and it is distributed in Costa Rica near the continental divide of the central volcanic highlands and is common in open sites and on roadsides (2,3).

Previous Work

Previous work with P. eminens from Guatemala (4), Mexico (5,6) and Costa Rica (7) revealed the presence of several sesquiterpene lactones, some of which possessed molluscicidal (5) and anti-inflammatory (7) activities. To the best of our knowledge nothing has been reported concerning the oil composition of this plant.

Present Work

The oil was analyzed by GC/MS using a Hewlett-Packard G1800A GCD System. The data were obtained on a 5% methyl phenyl silicone fused silica capillary column, 30 m � 0.25 mm (film thickness 0.25 �). Operation conditions were: carrier gas, he (1.0 mL/min); oven temperature program, 75�C (4 min), 75�-200�C at 3�C/ min, 200�C (8 min); sample injection port temperature, 250�C; detector temperature, 260�C; ionization voltage, 70 eV; scanning over 38-400 amu range; split injection, 1:20.

Individual components of the oil were identified by comparison of their retention indices, and by spectrometric analyses using a computerized library MS search or by using visual mass spectra comparison data with those published in the literature (8,9) or those from our own database. Components were quantified as area percentage of total volatiles without correction factor.

Seventy-three compounds representing ca. 88% of the oil were identified (Table I). The main constituent was (e) -nerolidol (46.7%), followed by minor amounts of [alpha]-pinene (14.9%), [beta]-caryophyllene (6.2%) and germacrene D (4.9%). (e) -nerolidol was identified also using ^sup 1^H- and ^sup 13^C-NMR spectra obtained on a Varian HA 400 spectrometer (CDCl^sub 3^, TMS). The assignments for these spectra are in agreement with those reported in the literature (10). Minor amounts of compounds with eudesmane skeleton were detected in the oil; [delta]-selinene, [beta]-selinene (24%), [beta]-eudesmol and [beta]-oostol (0,4%), some possible, preeurserg of eostie aeid, whieh is structurally related to three recently isolated unusual esters of guaianyl sequiterpene lagtones (6,7), We also found a small quantity of the diterpene abienol (0,6%), previously isolated from a plant sample eolleeted in Guatemala (4),

Acknowledgments

The authors are grateful to Vieerreetorfa de Imestigacion (UCR) und CYTKD (Projeots 809-93-600 and JV-6) for finanoial and technical support and to L.J. Poveda (Escuela de Ciencias Ambientales, UNA) for the botanical identification. To M. Segnini and Centra de Investigacion en Contaminacion Ambiebtal (International Atomic Energy Agency, proj. 802-96-550) for GC/MS facilities. To E. Alvarado (Unidad de RMN, UCR) for running the NMR speotra and to N.R. Farnswerth (College of Pharmacy, University of Illinois at Chicago) for his help to access the NAPRALERT database.

References

1. L.R, Holdridge, Ecologia basada en zonas de vida, p, 219, Instituto Interamericano de Cooperapion para Ia Agrioulturi, San Jose, Costa Rica (1987).

2. P.C. Stanciley, Flora of Costa Rica. Field Museum of Natural History, Chicago, 19 (part 3), 1506 (193B),

3. L.R. Holdridge, LJ. Poveda and Q. Jimenez, Arboles de Costa Rica, p. 451, Vol. 1. Centra Cientffico Tropical, San Jose, Costa Rica (1997).

4. F. Bohlmann and N. Le Van, Neue Quajaneliae sue Peasehaenium eminens. Phytochemistry, 16, 1304-1305 (1977),

5. F.B. Fronczek, D. Vargas, N.H. Fischer and K, Hostettmann, The molecular structure of 7[alpha]-hydroxy-3-desoxy-zaluzanin C, a molluscicidal sesquiterpene lactone. J. Nat. Prod., 47, 1036-1039 (1984).

6. A. Ortega, R.A. Toscano and E. Maldonado, A costic acid gualanylester and other constituents of Podachaenium eminens. Phytochemistry, 49, 1085-1090(1998).