Distinguishing between toxic and non-toxic pyrrolizidine alkaloids and quantification by liquid chromatography-mass spectrometry

Abstract

Pyrrolizidine alkaloids (PAs) are important plant toxins causing poisoning in livestock, leading to significant financial and production losses each year. It may also enter the human food chain as contaminants of grains, via animal products such as milk, eggs and honey or herbal remedies. Not all PAs are toxic and it is important to be able to distinguish between toxic and non-toxic PAs. We developed a sensitive and selective analytical method to determine toxic 1,2-unsaturated PAs concentrations in plant extracts by liquid chromatography–mass spectrometry (LC–MS) with electrospray ionization and precursor ion experiments. Multi-reaction-mode experiments were used to quantify the concentrations of the different unsaturated PAs and results were expressed as mg/g retrorsine equivalents. The results obtained on Crotalaria sphaerocarpa contaminating maize crops have important implications.