Submitted to: Journal of Essential Oil Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 9, 2001
Publication Date: March 1, 2003
Citation: LUCERO, M.E., ESTELL, R.E., FREDRICKSON, E.L. THE ESSENTIAL OIL COMPOSITION OF PSOROTHAMNUS SCOPARIUS. JOURNAL OF ESSENTIAL OIL RESEARCH. 2003. V. 15. P. 108-111. Interpretive Summary: Shrubs are increasing on arid grasslands at an alarming rate, and hypotheses explaining these increases abound. However, most will agree that this trend, which proceeds at the expense of grasses, is undesirable. Many desert shrubs are usually unpalatable to livestock and wildlife, and shrubs are less effective than grasses at stabilizing soil and protecting watersheds. For these reasons, a long-term goal of our research is to identify factors contributing to the success of shrubs and to devise noninvasive methods for restoring grasslands. It is known plants interact with their surroundings by producing diverse arrays of chemicals, which act to kill pathogens, deter herbivores, attract pollinators, filter sunlight, and inhibit growth of neighboring plants. The array of chemicals produced by a given plant species are unique and may include hundreds of individual compounds. By identifying the compounds present in various desert shrubs, we hope to identify keys to their successful competition on rangelands. I this study, we have identified 64 volatile compounds produced by Psorothamnus scoparius, commonly known as broom dalea. Some of these compounds are known to deter herbivory in other plants and possibly serve the same purpose here. In addition, we have provided the mass spectra for 15 chemicals that do not appear in available mass spectral databases and are possibly novel compounds.
Technical Abstract: Psorothamnus scoparius (broom dalea) was collected from the Jornada Experimental Range in south central New Mexico. Current year's growth was collected from 10 plants, all found within an approximate 50 m radius of the GPS coordinates N 32 deg 41.286' and W 106 deg 46.922' during June 2000. Composite samples were steam distilled, and the essential oil was analyzed using GC with FID and GC/MS. Mass spectra and retention indices were used to identify 65 previously described compounds. Retention indices and EI mass spectra are also provided for 15 unknowns. Gamma-terpinene (22.3%), para-cymene (14.0%), and alpha-pinene (9.0%) were the major constituents of the oil.