Lupine alkaloids are natural substances classified as quinolizidine alkaloids. They are named after their presence in lupins.
Depending on the variety, lupins contain between 0.6% and 4.3% lupine alkaloids.
More than 170 lupine alkaloids have been identified. The primary alkaloid is lupinin. Other notable compounds include lupanine, lupinine, lupanolin and sparteine. (-)-Lupanine is found in the white lupin, while (+)-lupanine is present in the blue lupin. Both (+)-sparteine and (-)-sparteine occur naturally. (-)-cytisine, the primary alkaloid of the laburnum, is also classified as a lupine alkaloid.
Lupine alkaloids are considered toxic. Grazing animals should not ingest more than 60 g/kg. Symptoms of poisoning include liver and kidney degeneration, miscarriages, and congenital deformities. Sheep are particularly sensitive to these toxins.