Research Group Biochemical Ecology and Molecular Evolution

Pyrrolizidine alkaloids - efficient protection against herbivores

In the focus of our research are pyrrolizidine alkaloids (abbreviated as PAs), product of specific plants with toxic potential. But what are alkaloids? Several compounds that are beneficial for humans belong to the alkaloids. They are used for example as medicals, narcotics, or stimulants.  Our daily life would be different without caffeine, nicotine, or morphine and cocaine. All of them are products of plant secondary metabolism.

Certain plants use pyrrolizidine alkaloids for defence

Pyrrolizidine alkaloids are produced only by specific plant lineages. For example, certain species of the sunflower family produce PAs, like the common ragwort, or of the legume family as part of their secondary metabolism. The PAs are used as defence against herbivores. Some of them are very toxic and might be dangerous for humans and grazing livestock.

Pyrrolizidine alkaloids are toxic of humans and animals

PAs are not toxic for the plants producing them. In plants, they occur in a non-toxic form. Only after they have been ingested, animals get problems. In the gut these alkaloids are transferred into a toxic form. That is why most animals avoid PA-containing plants, at least, as long as the plants have not been harvested during hay making. As part of the hay, the animals are unable to identify the toxic plant parts.

Of note, some specialized insects are not only able to feed on these toxic compounds without and negative effects, but they accumulate these toxins in their own body to protect themselves against predators.

Further background informations

Here you find a short introduction to aspects related to our research.

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Secondary
metabolism
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Pyrrolizidine
alkaloids (PAs)
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Insect
adaptations