Journal of Chemical Ecology

, Volume 45, Issue 2, pp 128–135 | Cite as

Specific Distribution of Pyrrolizidine Alkaloids in Floral Parts of Comfrey (Symphytum officinale) and its Implications for Flower Ecology

  • Thomas Stegemann
  • Lars H. Kruse
  • Moritz Brütt
  • Dietrich OberEmail author


Pyrrolizidine alkaloids (PAs) are a typical class of plant secondary metabolites that are constitutively produced as part of the plant’s chemical defense. While roots are a well-established site of pyrrolizidine alkaloid biosynthesis, comfrey plants (Symphytum officinale; Boraginaceae) have been shown to additionally activate alkaloid production in specialized leaves and accumulate PAs in flowers during a short developmental stage in inflorescence development. To gain a better understanding of the accumulation and role of PAs in comfrey flowers and fruits, we have dissected and analyzed their tissues for PA content and patterns. PAs are almost exclusively accumulated in the ovaries, while petals, sepals, and pollen hardly contain PAs. High levels of PAs are detectable in the fruit, but the elaiosome was shown to be PA free. The absence of 7-acetyllycopsamine in floral parts while present in leaves and roots suggests that the additional site of PA biosynthesis provides the pool of PAs for translocation to floral structures. Our data suggest that PA accumulation has to be understood as a highly dynamic system resulting from a combination of efficient transport and additional sites of synthesis that are only temporarily active. Our findings are further discussed in the context of the ecological roles of PAs in comfrey flowers.


Constitutive defense Variability Plant secondary metabolism Alkaloid biosynthesis Elaiosome GC-MS 



We thank Karina Thöle, Brigitte Schemmerling, and Margret Doose for support in the laboratory. We thank Dr. Dorothee Langel for the foto stacking of Symphytum pollen and Britta Milewski for discussions on the manuscript.


This work was supported by a grant of the Deutsche Forschungsgemeinschaft to DO (OB 162/7–2).

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest.

Supplementary material

10886_2018_990_MOESM1_ESM.docx (21 kb)
ESM 1 (DOCX 21 kb)


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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Botanisches Institut und Botanischer GartenChristian-Albrechts-Universität zu KielKielGermany
  2. 2.Plant Biology Section, School of Integrative Plant SciencesCornell UniversityIthacaUSA

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