Al. Perezcastorena et al., CALLOSINE, A 3-ALKYL-SUBSTITUTED PYRROLIZIDINE ALKALOID FROM SENECIO-CALLOSUS, Journal of natural products, 61(10), 1998, pp. 1288-1291
Two collections of Senecio callosus from different regions of Mexico c
ontained a structural diversity of pyrrolizidine alkaloids (PAs), whic
h may contribute to the easy adaptation of this species. In addition t
o some known compounds, two new PAs (1 and 2) were isolated, and their
structures were established by chemical transformations and spectrosc
opic studies.