TECHNICAL NOTE - A COMPARISON OF TECHNIQUES FOR EXTRACTING MONOTERPENOIDS FROM JUNIPERUS (CUPRESSACEAE) SPECIES

Concentration and composition of monoterpenoids in plant tissue affect s a variety of environmental and ecological issues such as plant defen ses, plant classification, and phytotoxicity, Developing the technique s for extracting and estimating the concentration and composition of m onoterpenoids must be species-specific because monoterpenoid storage l ocation varies between species. Ashe juniper (Juniperus ashei Buchholz ) and redberry juniper (J. pinchotii Sudw) are 2 cooccurring species w hich differ in palatability and preference. The objective of this stud y was to determine which of 2 common extraction techniques provided th e best estimate of the concentration and composition of monoterpenoids in mature plant tissue. Two extraction techniques were tested by soak ing crushed juniper needles in hexane solvent for 6, 12, 18 and 24 hou rs or by steam distilling samples for 2, 4, 6, or 8 hours, The extract s were analyzed by using 2 different analytical columns in separate ga s chromatographs. The hexane solvent soak, regardless of time in the s olvent, yielded a lower total concentration and a decreased compositio nal diversity of monoterpenoids compared to the steam distillation tec hnique, An 8-hour steam distillation yielded the greatest concentratio n and composition of monoterpenoids, Both types of analytical columns resulted in similar estimates of monoterpenoid concentrations and comp osition.