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
Alkaloid profiles of five Senecio species (Asteraceae), including S. ambiguus subsp. ambiguus, S. ambiguus subsp. nebrodensis, S. gibbosus subsp. bicolor, S. gibbosus subsp. gibbosus, and S. gibbosus subsp. cineraria, were studied. Eleven pyrrolizidine alkaloids were identified and their content was