Occurrence concentration and toxicity of pyrrolizidine alkaloids in crotalaria seeds

Seed of 41 accessions of Crotalaria representing 35 species were analyzed for the concentration of total pyrrolizidine alkaloids (PAs) and for oral toxicity to 1-week-old chicks. All accessions were assayed for the presence of monocrotaline and spectabiline by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC). High concentrations of PA were found in the seed of Crotalaria spectabilis Roth # CVTSP (3.85%), C. retusa L. (2.69%), C. alata Leveille (1.60%), C. quinquefolia L. (1.19%), and C. argyrolobioides Bak. (1.01%). The seed of Crotalaria argyrolobioides produced toxic signs but no deaths when fed at 10 mg/g of body weight, whereas the seed of the other four species were 100% lethal when fed to chicks in one dose at 2 to 6 mg/g of body weight. Seed of other species contained less than 0.6% PA and were nontoxic to chicks fed one dose at 10 mg/g of body weight. Monocrotaline was identified in 17 accessions and spectabiline in 7. No species contained both monocrotaline and spectabiline.