Pyrrolizidine alkaloids from Senecio gallicus and S. Adonidifolius

Abstract Four alkaloids, ligularizine, senkirkine and senecionine N-oxide, were isolated from S. gallicus. Apart from florosenine, a new alkaloid was isolated from S. adonidifolius and identified as 12,13,19-trihydroxy-15,20-epoxy-15,20-dihydro(12S,15R,20R senecionan-11,16-dione. Two dimensional spectroscopic correlation experiments (1H1H and 13C1H) were performed, permitting the unequivocal assignation of the 1H and 13C NMR spectra of the alkaloids and enabling us to correct some of the data appearing in the literature.