Composition of the Essential Oil from Leaves of Smallanthus maculatus (Cav.) H. Rob. (Asteraceae)

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

Abstract

The composition of the essential oil from leaves of Smallanthus maculatus (Cav.) H. Rob. from Costa Rica was analyzed by capillary GC/MS. Fifty-seven compounds were identified corresponding to ca. 96% of the oil. The major components were [alpha]-pinene (32.9%), germacrene D (13.7%) and [beta]-caryophyllene (10.7%).

Key Word Index

Smallanthus maculatus, Asteraceae, essential oil composition, [alpha]-pinene, germacrene D, [beta]-caryophyllene.

Plant Name

Smallanthus maculatus (Cav.) H. Rob., (syn: Polymnia maculata Cav.), Asteraceae, tribe Heliantheae, subtribe Melampodiinae.

Source

Fresh leaves of flowering plants oi Smallanthus maculatus from Costa Rica, were collected from the grounds of the University of Costa Rica Campus (San Pedro de Montes de Oca, Province of San Jose) at an elevation of 1150 m. A voucher specimen was deposited in the Herbarium of the University of Costa Rica at the School of Biology (USJ 75500).

Plant and Plant Distribution

Smallanthus maculatus is an erect, coarse herb (1-2 m tall); often much branched with purple-spotted stems with sparsely short hairs. The leaves (ca. 10-30 cm long) are opposite, with long winged petioles, and the blades are triangular to broadly ovate, triplinerved with margins very coarse and irregularly dentate. The flowers are numerous and form corymbiform panicles with yellow corollas (1). Smallanthus maculatus grows on moist forest thickets and edges, and it is common as a weed in cultivated ground. It is distributed from southern Mexico to Panama. It is called colloquially 'purca" (Indian origin) or 'tora.' It is distributed in the central region of Costa Rica from 600 to 2400 m elevation (2).

Previous Work

Several members of the genus Smallanthus have been investigated chemically. They are characterized mainly by the occurrence of sesquiterpene lactones of the melampolide type (3-11) and diterpenes of the ent-kaurene type (4-7,9) with one citation of sesquiterpenoids of the cadinane skeleton (12). These plants have also been reported to contain pentyne compounds (13), flavonoids and esters of cinnamic acid (14).

Early works on the phytochemistry of S. maculatus (P, miculata) revealed the presence of sesquiterpene lactones (3,5,9) and diterpenes (5). Extracts of the dried leaves and some sesquiterpene lactones isolated from the plant collected in Mexico have shown potent inhibition of the transcription factor NF-kB (15).

To the best of our knowledge nothing has been reported concerning the composition of the essential oil of this plant.

Present Work

Fresh leaves were subjected to hydrodistillation for 3 h using a modified Clevenger-type apparatus. The distilled oil was collected and dried over anhydrous sodium sulphate and stored in a freezer (0°-10°C). The oil yield was 0.1% (w/w).

The GC/MS analyses were performed using a Shimadzu GCMS-QP5050 apparatus and CLASS 5000 software with Wileyl38 computer database. The data were obtained on a 5% methyl phenyl silicone fused silica capillary column (30 m × 0.25 mm, film thickness 0.25 µm). Operation conditions were: carrier gas, He; flow, 1.0 mL/min; oven temperature program, 60°-240°C at 2°C/min; sample injection port temperature, 250°C; detection temperature, 260°C; ionization voltage, 70 eV; ionization current, 60 µA; scanning speed, 0.5 s over 38-400 amu range; split, 1:70.

Identification of the components of the oil was performed using the retention indices on DB-5, and by comparison of their mass spectra with those published in the literature (16-19) or those of our own database.

The composition of the oil from the leaves of S. maculatus is summarized in Table I. Fifty-seven compounds were identified accounting for over 96% of the composition of the oil. The terpene hydrocarbons amounted to about 9f% with minor percentages of oxygenated compounds (5.5%). The oil was dominated by [alpha]-pinene (ca. 33%), with moderate amounts of [beta]-pinene (7.1%), camphene (5.4%), sabinene (4.8%), [beta]-caryophyllene (10.7%), germacrene D (13.7%) and bicyclogermacrene (6.6%).

Acknowledgments

The author is grateful to Vicerrectoria de Investigation UCR (Project 809-93-600) for financial support, to L. Hernandez (CIPRONA) for her technical assistance, and to N. R. Farnsworth (College of Pharmacy, University of Illinois at Chicago) for his help to access the NAPRALERT database.

References

1. D.L. Nash, Tribe V, Heliantheae. In: Flora of Guatemala. Edits., D.L. Nash and L.O. Williams, Pan XII. Fieldiana Botany, 24, p. 291, Field Museum Natural History Pabl., Chicago (1976).

2. J. Leon and LJ. Poveda, Nombres comunes de las plantas de Costa Rica. Ed. Guayacan, San Jose, C.R. p. 573 (2000).

3. W. Herz and S.V. Bhat, Maculatin: an Isomer of Uvedalin Epoxide from Polymnia maculata. Phytoohemistry, 12, 1737-1740 (1973).

4. F. Bohlmann, J. Jakupovic, C. Zdero, R.M. King and H. Robinson, Neue Melampolide und cis,cis-Germacranolide aus Vertretern der Subtribus Melampodiinae. Phytochemistry, 18, 625-630 (1979).

5. N. Le Van and N.H. Fischer, Three New Melampolide sesquiterpenes, Polymatin A, B and C, from Po/ymnia maculata Cav. var. maculata. Phytochemistry, 18, 851-854 (1979).