For those of us in the Northern Hemisphere, the last few weeks have marked the beginning of spring. The trees are in blossom, the days are getting longer and the collective improvement in mood is almost palpable.
However, spring brings its own dangers, as I was reminded last week. I was asked for my professional advice on the potential lethality of the daffodil. The requester had just witnessed her child sucking the cut end of a daffodil. She was aware that daffodils could be poisonous and was being vigilant about adverse effects – what should she expect?
Daffodils form part of the genus Narcissi and family Amaryllidaceae, and have been considered toxic for many years. The adverse effects are due to a compound called lycorine, which if ingested in fairly large quantities, can cause vomiting, diarrhoea and rarely, seizures and death. In practice, clinical effects typically affect dogs or children who ingest daffodil bulbs, which contain more toxin than flowers, stems or leaves. Daffodil bulbs can easily be mistaken for onions. In the majority, symptoms typically last for several hours and subside with no known longer-term side effects. Even in an infant, it is unlikely that sucking the cut end of a daffodil will result in the ingestion of enough toxin to cause clinical sequelae.
The chemistry of molecules like lycorine (the Amaryllidaceae alkaloids) is complex and evidence of their biological action has been inconsistent. Lycorine is known to interfere with cell protein translation, possibly by binding to the ribosome or by interfering with the initiation of translation. It may also have an effect on cellular apoptosis. This feature of the toxin has prompted interest in the possible medicinal benefits of the Amaryllidaceae alkaloids. One member of this group, Galantamine, is used in the treatment of Alzheimer’s disease. There is also interest in the use of these alkaloids in the treatment of malignancy. Indeed, there is some evidence that the Amaryllidaceae have been used in antiquity as anti-cancer treatments. Our predecessors in medicine, Pliny the elder and Hippocrates, used these plants in the treatment of cancers around two thousand years ago. Lycorine is therefore a good example of Paracelsian concept, that the dose of an agent determines whether it is a toxin or a medicine1.
So, next time you walk past ‘a host of golden daffodils’, consider the dangers of spring and the biochemical potential that lies within.
1: This concept is widely attributed to Paracelsius. The original quote is from this book, although my poor German language skills sadly limit my ability to check this reference thoroughly! p. 435, Verkehrsmedizin: Fahreignung, Fahrsicherheit, Unfallrekonstruktion, B. Madea, F. Mußhoff, and G. Berghaus, Köln: Deutscher Ärzte-Verlag, 2007, ISBN 3-7691-0490-0.