Pine needle abortion in cattle: analysis of isocupressic acid in North American gymnosperms

Abstract

Isocupressic acid is a labdane resin acid found in Pinus ponderosa needles and causes abortion in late term pregnant cattle. A chemical survey was conducted to determine the phytochemical distribution of isocupressic acid in selected North American shrub and tree species with possible association with cattle abortions. A method of analysis for the evaluation of total available isocupressic acid (including hydrolysed acetyl and succinyl derivatives) was developed based on a base/acid extraction of dry, ground plant material, followed by detection and quantitative determination using capillary gas chromatography of the di-(trimethylsilyl)-derivative. Samples from 23 different species were collected throughout the western and southern regions of the United States and analysed. Isocupressic acid was detected in 15 species, and significant concentrations (>0.5% dry weight) were found in Pinus ponderosa, P. jeffreyi, P. contorta, Juniperus scopulorum, and J. communis. Copyright © 1999 John Wiley & Sons, Ltd.