Livestock poisoning in South America by species of the Senecio plant.

The pyrrolizidine alkaloids retrorsine, senecionine, integerrimine, neosenkirkine and florosenine were isolated from different Senecio spp. common in southern Brazil, Uruguay and Paraguay. Structure elucidation of these compounds was mainly accomplished by two-dimensional FT NMR techniques. Detailed interpretations of 1H-1H and 1H-13C NMR correlation spectra are given. The alkaloids neosenkirkine, integerrimine and florosenine were found in Senecio leptolobus De Candolle, retrorsine accompanied by senecionine in Senecio selloi (Spreng.) DC and Senecio cisplatinus Cabrera. In Senecio heterotrichus DC. integerrimine is accompanied by retrorsine. Investigations on pathology and histopathology of Senecio envenomation in Brazil are summarized.