The Chemical Constituents of Sagebrush Foliage and Their Isolation

Abstract

Five foliar constituents were measured seasonally from the three subspecies of big sagebrush in Montana. Monoterpene, crude terpenoid, and crude fat levels were lowest in the spring, increased through the summer with maximum quantities at flowering or in the fall and winter months thereafter. Crude protein and total nonstructural carbohydrates were at highest concentrations in the spring, decreased in the summer, and rose again in the fall. Sagebrush foliage consists of an external and internal component. The external material is glandular secondary metabolic products, primarily terpenoids, and cuticular waxes. The internal constituents are cell-wall polymers, protein, nonstructural carbohydrates, and lipids. A S-mhmte chloroform extraction of fresh whole leaves removed the external material (crude terpenoids) with minimal affect on the internal components. Steam distillation extracted the epidermal terpenoids and the internal nonstructural carbohydrates leaving the cuticular waxes and protein in the dry matter residue. Plants are capable of biosynthesizing a tremendous number of chemicals that have potential uses as food, fiber, fuels, and chemicals (Buchanan et al. 1978 a,b). Many of these resources, however, have been unutilized because of high costs, inadequate technology and limited knowledge of chemical composition. The rising cost of fossil fuels, particularly oil, has stimulated an interest in the chemicals and biomaterials that can bederived from plants. In the United States and Mexico research is being directed toward both native and introduced species that have evolved and adapted to the harsh semiarid and arid environments (Campos-Lopez and Roman-Alemany 1980, Johnson and Hinman 1980), where inadequate water supplies have limited agricultural development. On these drier sites, new crops could be established without affecting current food and fiber production. Big sagebrush (Artemisia tridentata) is an abundant shrub on semiarid rangelands with considerable economic and biological impact (Gifford et al. 1979). Its distribution and population densities have increased during the last century due to overgrazing of the associated grasses, fire control, and the shrubs' inherent resistance to herbivores (Morris et al. 1976, Younget al. 1979). Improvement of sagebrush-grasslands for livestock production is a desirable management practice and requires the eradication of sagebrush. This can be accomplished by a variety of techniques with variable costs and returns (Nielsen 1979). Harvesting the shrubs for their biomaterials might be a feasible alternative to destroying them and could provide some management flexibility for sagebrushgrasslands. Sagebrush biomass has two distinct components, wood and foliage. The stems and branches are primarily cell-wall polysaccharides held together with lignin and chemically similar to the wood of other angiosperms (Shafizadeh and Buckwa 1970). The foliage The authors are research associate professor, graduate student, and professor, Wood Chemistrv Laboratorv. Deoartment of Ch...

Sagebrush ingestion by lambs: Effects of experience and macronutrients

“…Sagebrush intake was highly variable for individual lambs. Terpene levels in sagebrush vary seasonally (Kelsey et al 1982), and sheep are most likely to use sagebrush when terpene concentrations are low and alternative forages are scarce (e.g. winter; Gade and Provenza 1986).…”

Phytochemistry predicts habitat selection by an avian herbivore at multiple spatial scales

“…Nutrient concentrations were quantified as percentage of dry mass. We chose monoterpenes and phenolics as PSM variables because both classes of compounds exert deleterious effects (e.g., toxicity, increased energy expenditure, nutrient binding) on herbivores (Dearing et al 2005) and occur in relatively high concentrations in sagebrush (Kelsey et al 1982). Monoterpenes were quantified as area under the gas chromatogram curve/100 lg dry mass (AUC/100 lg; Appendix B), and total phenolic concentrations were quantified as lmol gallic acid equivalents/g dry mass (Appendix C).…”

“…leaves from late autumn through early spring (Wallestad et al 1975). Sagebrush foliage contains relatively high concentrations of PSMs (e.g., monoterpenes, sesquiterpene lactones, phenolics; Kelsey et al 1982) and previous work has suggested that Sage-Grouse browse sagebrush selectively with respect to nutrients and PSMs (Remington andBraun 1985, Welch et al 1988). We evaluated the effects of nutrients and PSMs on Sage-Grouse habitat selection at three spatial scales: (1) selection of sagebrush habitat type, (2) selection of patches within a given habitat type, and (3) selection of plants within a given patch (i.e., diet selection).…”

Journal of Range Management, Volume 53, Number 1 (January 2000)

“…These findings suggest toxic compounds in sagebrush limited the amount of sagebrush lambs could consume. Sagebrush contains a diverse array of terpenes (Kelsey et al 1982, Bray et al 1991 that are potentially toxic (Johnson et al 1976). Thus, we hypothesize terpenes set a limit on the amount of food lambs consumed (i.e., toxin satiation).…”