Technical Note: A Comparison of Techniques for Extracting Monoterpenoids from Juniperus (Cupressaceae) Species

Abstract

Concentration and composition of monoterpenoids in plant tissue affects a variety of environmental and ecological issues such as plant defenses, plant classification, and phytotoxicity. Developing the techniques for extracting and estimating the concentration and composition of monoterpenoids must be speciesspecific because monoterpenoid storage location varies between species. Ashe juniper f,Juniperus ashei Buchholz) and redberry juniper t,J. pinchotii Sudw) are 2 co-occurring species which differ in palatability and preference. The objective of this study was to determine which of 2 common extraction techniques provided the best estimate of the concentration and composition of monoterpenoids in mature plant tissue. Two extraction techniques were tested by soaking crushed juniper needles in hexane solvent for 6, 12, 18 and 24 hours or by steam distilling samples for 2,4,6, or 8 hours. The extracts were analyzed by using 2 different analytical columns in separate gas chromatographs. The hexane solvent soak, regardless of time in the solvent, yielded a lower total concentration and a decreased compositional diversity of monoterpenoids compared to the steam distillation technique. An g-hour steam distillation yielded the greatest concentration and composition of monoterpenoids. Both types of analytical columns resulted in similar estimates of monoterpenoid concentrations and composition.

Feeding Redberry Juniper (Juniperus pinchotii) at Weaning Increases Juniper Consumption by Goats on Pasture

“…kg 21 BW), cellular necrosis and lobular encapsulation were evident (Straka et al 2004). Goats typically avoid juniper during the spring and summer and when alternative herbaceous forage is available (monoterpene levels are also reportedly higher; Riddle et al 1996;Owens et al 1998b). In contrast, conditioned goats selected juniper every month of this study except March and April, when herbaceous forage intake increased.…”

“…In this study, increased exposure time may have increased intake to the point of goats receiving aversive postingestive feedback and caused the formation of a mild aversion to juniper during the initial days of the conditioning trial. Monoterpene levels in juniper vary monthly (Owens et al 1998b) and probably vary from year to year depending on ambient conditions. The redberry juniper fed in the preconditioning phase of this study may have contained higher monoterpene levels than juniper fed in previous years.…”

Headspace solid-phase microextraction (HS-SPME): a microscale sampling technique for determination of monoterpene hydrocarbons in coniferous needles by gas chromatography/mass spectrometry (GC/MS)

“…The time needed to reach equilibrium between the gaseous phase and the polymeric liquid layer was determined at 50-53°C for different exposure times (5,10,15,20,30,40, 50, 60, 90, 120, 150, 180, 240 and 300 s) at a constant concentration of the MTHs in a vial. From the results for camphene, myrcene, limonene and other MTHs (results not given), a 120-s period was selected as fully sufficient to reach quantitative sorption (>99.5%).…”

“…The amount of isolated essential oil and its qualitative composition depend to a great extent on the experimental conditions during the extraction and on the isolation procedure used. The steam distillation [4,5], simultaneous distillation and extraction (SDE) [6,7], solvent extraction [4,5,8,9,10] and supercritical fluid extraction (SFE) [6,11,12,13] are the most widely used procedures. Unfortunately, most of them are time consuming and need a large amount of sample (tenths or units of grams).…”

Age and Body Condition of Goats Influence Consumption of Juniper and Monoterpene-Treated Feed

“…The terpenes were applied to a bluegrass pelleted feed at a concentration of 20.8 g of monoterepenes ? kg 21 of feed (as-fed basis), which is double the total concentration of monoterpenes in redberry juniper foliage (Owens et al 1998). We used a very high concentration of monoterpenes in an attempt to establish a threshold where LBC animals might have to decrease intake of the chemically defended plant.…”