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

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