Submitted to: Journal of Essential Oil Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/9/2004
Publication Date: 4/1/2006
Citation: Lucero, M.E., Fredrickson, E.L., Estell, R.E., Morrison, A.A., Richman, D.B. 2006. Volatile composition of Gutierrezia sarothrae (Broom Snakeweed) as determined by steam distillation and solid phase microextraction. Journal of Essential Oil Research. 18:121-125.
Interpretive Summary: Guiterrizia sarothrae (broom snakeweed, snakeweed, terpentine weed) is a prevalent species on rangelands throughout much of the western United States. The plant has been used for centuries to treat various human ailments and can be found in contemporary herb shops. Efforts to eliminate snakeweed are common among land managers striving to maximize forage production and livestock health. As such, an extensive research database exists surrounding the growth habits, mammalian toxicity, and nonvolatile chemistry of G. sarothrae. Here, we describe 97 volatile compounds extracted from snakeweed leaves and stems, 80 of which have never before reported in G. sarothrae. All the compounds we report were extracted from snakeweed collected from the Chihuahuan Desert of southern New Mexico. The compounds limonene (10.4%), beta-pinene (9.6%), beta-eudesmol (8.0%), sabinene (7.8%), cryptone (6.5%), alpha-pinene (5.5%), and ortho-cymene (5.2%) accounted for 53.0% of the volatiles extracted from headspaces of vials containing ground G. sarothrae stems. All of these compounds are commonly reported components of plant essential oils and have medicinal properties. While our own investigations will continue to examine the role these volatiles play in rangeland ecology, we believe the wealth of existing chemical, toxicological, ethnobotanical and growth hardiness data available for G. sarothrae provide an extensive foundation from which to study the pharmaceutical properties of its extracts. Since snakeweed preparations continue to be sold in herb shops for human consumption, it stands to reason the general public would benefit from additional information regarding the safety and utility of these products. We hope the data presented here will stimulate interest in such studies.
Technical Abstract: Guiterrizia sarothrae (broom snakeweed, snakeweed) is a prevalent species on rangelands throughout much of the western United States. This plant has been intensely studied in order to minimize its negative impact on forage production and livestock health. Although G. sarothrae has been used for centuries to remedy various ailments, scientific investigations of the plant¿s medicinal value are difficult to find in the literature. The objective of this study was to explore the volatile chemical composition of G. sarothrae. Shoots from 88 actively growing plants showing no signs of root borer infestation were selected from five sites on the Chihuahuan Desert of southern New Mexico. Volatiles were extracted from ground, composite tissues by steam distillation and by solid phase microextraction (SPME), then separated and analyzed by gas chromatography with mass spectral and flame ionization detection. Comparing retention indices and mass spectra to known compounds identified ninety chemicals. Retention indices and 70 eV mass spectra are also provided for seven unknowns. Compounds detected varied in quantity between extraction protocols. In oil, cryptone (6.4%) and beta-eudesmol (5.9%) were the only compounds comprising more than 5% of the chromatographic peak area. In samples prepared by solid-phase microextraction, limonene (10.4%), beta-pinene (9.6%), beta-eudesmol (8.0%), sabinene (7.8%), cryptone (6.5%), alpha-pinene (5.5%), and ortho-cymene (5.2%) accounted for 53% of the extracted volatiles. The results presented reveal a complex volatile composition from which unique compounds may still be identified.