Analysis of loline alkaloids in endophyte-infected tall fescue by capillary gas chromatography

Abstract

A capillary gas chromatographic method for routine analysis of loline-type alkaloids in tall fescue seed and forage has been developed. Filtered solvent extracts of seed, in CH,Cl,/MeOH/NH,OH (75:25:0.5), with phenylmorpholine as an internal standard were normally suitable for direct GC analysis; however, forage extracts required additional cleanup by ion exchange to remove interfering substances. Peak identities were confirmed by mass spectrometry and comparison to known standards. The method should be useful in studies concerning the relationships between loline alkaloid concentration in grasses, insect resistance, and performance problems in cattle. Tall fescue, Festuca arundinacea Schreb, is a coolseason pasture grass that is used extensively in the southeastern United States. Most existing pastures are infected with an endophytic fungus, Acremonium coenophialum Morgan Jones and Gams, and A. coenophialum infected tall fescue is known to contain a variety of alkaloids (Figure 1). The ergot-type alkaloids, such as ergovaline and ergonovine, and the loline-type alkaloids, mainly Nformyl- and N-acetylloline, have not been found in tall fescue when the endophyte is absent. These two classes of alkaloids have been associated with production losses in cattle (Sanchez, 1987), and economic losses to cattle producers have been estimated at $50 to $200 million annually (Siege1 et al., 1984).