Seasonal variability in pyrrolizidine alkaloids in Senecio inaequidens from the Val Venosta (Northern Italy)

Abstract

Senecio inaequidens is a neophyte originating from South Africa that has managed to spread to Europe and colonize large areas. This plant has toxic pyrrolizidine alkaloids (PAs) that represent a health risk to humans and animals. The aim of this work was to measure the content of PAs of these plants in continuous intervals over the entire growing season. The plants were separated into their organs, such as sprouts, stems, leaves and inflorescences. PAs were extracted from the dried plants using an acidic methanol solution, purified and measured by GC/MS. The average PA content of plants over the growing season was 0.33% of dry weight. The highest PA levels were about 1% in the dry weight and were found in the young sprouts and flower heads. There were nine PAs present, of which six could be identified. The main alkaloid was retrorsine followed by senecivernine, senecionine, integerrimine, usaramine and seneciphylline. Due to the high PA content of the inflorescences, the long flowering period and the rapid invasion dynamics, this species presents a high health risk for humans and animals.

Keywords::

• Senecio inaequidens
• neophyte
• pyrrolizidine alkaloids
• retrorsine
• senecivernine
• senecionine
• integerrimine
• usaramine
• seneciphylline
• poisonous plants
• vegetation period
• alkaloid content
• alkaloid spectrum
• shoots
• stems
• leaves
• flowers
• gas chromatography
• mass spectrometry

Acknowledgements

Thanks to Mrs Hanneliese Michitsch for her technical assistance. Dr. T Wilhalm, Museo Scienze Naturali Alto Adige, Bolzano (Italy), provided data on the distribution of S. inaequidens in Trentino-Alto-Adige region.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported with a grant to A. Eller by the Autonomous Province of Bolzano.