Organ-specific Distribution and Accumulation of Pyrrolizidine Alkaloids during the Life History of two Annual Senecio Species

摘要: Summary The pyrrolizidine alkaloids of the two annual Senecio species S. vernalis and vulgaris were separated by capillary gas-liquid chromatography. individual constituents isolated identified mass spectrometry 13 C NMR. alkaloid content, concentration, composition was evaluated quantitatively for different plant organs at various developmental stages species. highest content found in flower heads, 70 % 90 total , respectively. More than these present as N-oxides. Analysis single capitulae revealed about to be localized tubular florets, preferably floral tubes. inflorescences exhibit concentrations too (ca. 1.0–1.4 mg/g fr. wt.) which are 5–10 fold higher those leaves roots. In senkirkine, does not exist N-oxide, dominating leaves, whereas N-oxides senecionine followed senecivernine, seneciphylline, integerrimine, retrorsine dominated flowers. main both role type is discussed.