Pyrrolizidine alkaloids in some species of Senecio Linnaeus (Senecioneae: Asteraceae)

Pyrrolizidine alkaloids were analyzed by Gas Chromatography Mass Spectrometry in five species of Senecio Linnaeus viz. Senecio laetus Edgew, Senecio nudicaulis Buch.-Ham. ex D. Don, Senecio raphanifolius Wall. ex DC., from series Erucifolii of section Jacobaea; Senecio royleanus DC., from series Nemorenses of section Jacobaea and Senecio scandens Buch.-Ham. ex D. Don. from section Flexicaulis, of tribe Senecioneae of family Asteraceae. Presence of five types of pyrrolizidine alkaloids viz. Senecionine, Seneciphylline, Integerrimine, Platyphylline and Jacozine have been confirmed in four different species of Senecio Linn. Presence of pyrrolizidine alkaloid is not confirmed in one species, S. nudicaulis. Different types of pyrrolizidine alkaloids are found to be taxonomically significant in infrageneric level. The section Jacobaea is characterized by the absence of pyrrolizidine alkaloid jacozine while section Flexicaulis is characterized by the presence jacozine. Within the section Jacobaea, the series Nemorenses is characterized by platyphylline and the series Erucifolii by Seneciphylline. Within the series Erucifolii, the Senecio laetus is characterized by senecionine and the Senecio raphanifolius by intergerrimine. As the presence of pyrrolizidine is not confirmed in the Senecio nudicaulis of series Erucifolii of section Jacobaea, revealing it as distantly related to its group members, S. laetus and S. raphanifolius; the fact is also revealed by the morphology based cluster analysis carried on the species of Senecio found in Nepal Himalaya. Thus it reflects that the pyrrolizidine alkaloids are in good correlation with the morphological data in genus Senecio Linn. and could be a good taxonomic marker at the infrageneric level.