Sesquiterpene lactone
Other plant families with SLs are Umbelliferae (celery, parsley, carrots) and Magnoliaceae (magnolias).
[1] They can be allergenic and toxic in grazing livestock[2] causing severe neurological problems in horses.
Sesquiterpene lactones can be divided into several main classes including germacranolides, heliangolides, guaianolides, pseudoguaianolides, hypocretenolides, and eudesmanolides.
Artemisinin, a new, highly-effective anti-malarial compound, is a sesquiterpene lactone found in Artemisia annua.
Lactucin, desoxylactucin, lactucopicrin, lactucin-15-oxalate, lactucopicrin-15-oxalate are some of the most prominent found in lettuce and spinach, giving most of the bitter taste to these crops.
A : Germacranolides , B : Heliangolides, C + D : Guaianolides, E : Pseudoguaianolides, F : Hypocretenolides, G : Eudesmanolides.