Senecio inaequidens is a poisonous plant which has been introduced from Southern Africa to Europe, America, Asia and Australia in the last century. In Europe it is amongst the most quickly spreading neophytes. This species has managed to colonize great parts of continental Europe. Within the last years an increasing number of observations documented the plants rapid proliferation in new areas and thus the colonization of whole regions in large populations. The plant forms phytochemicals, so-called pyrrolizidine alkaloids, which protect it from herbivory. These alkaloids are ingested by herbivores and transformed into toxic pyrrole derivatives. These cause a type of poisoning in mammals which is commonly known as seneciosis. Senecio inaequidens poses a health risk for humans and animals alike due to its rapid dynamic of invasion and its toxic effect. It was the goal of this essay to better quantify this plant's content of pyrrolizidine alkaloids. Therefore the toxic substances were measured at regular intervals over the whole growth season. The alkaloids were measured by GC/MS in the selected ion monitoring mode in the plant extracts after an appropriate reduction and clean up step. The total amount was measured quantitatively in the different plant parts, namely sprouts, stems, leaves and inflorescences and was then calculated for the whole plant. The average percentage of pyrrolizidine alkaloids in the plants over the whole growth season was 0,33% of the dry weight. The highest concentration was around 1% of the dry weight and was found in the young shoots and flower heads. Additionally, the individual pyrrolizidine alkaloids were quantified. Nine different alkaloids were found, of which six could be properly identified. The main alkaloid was retrorsine, followed by senecivernine, senecionine, integerrimine, usaramine and seneciphylline.
Pyrrolizidine alkaloids / Senecio inaequidens / neophyte / poisonous plants / vegetation period / retrorsine /senecivernine /senecionine / gas chromatography / mass spectrometry /
Publication(s) resulting from University thesis:
Eller, A; Chizzola, R
(2016): Seasonal variability in pyrrolizidine alkaloids in Senecio inaequidens from the Val Venosta (Northern Italy).
Plant Biosystems 2016; 150: 1306-1312