Furanocoumarins - the defence of wild Parsnip and Giant Hogweed – University of Copenhagen

NaToxAq > Toxin of the week > Furanocoumarins

24 September 2018

Furanocoumarins - the defence of wild Parsnip and Giant Hogweed

Natural toxin

A touch of the sap of the plants containing furanocoumarins causes painful inflammation of the skin and its long-lasting irritating sensitivity to sunlight. If ingested, furanocoumarins can cause liver damage and death.

Furanocoumarins are toxins of natural origin produced by a variety of plants. As their common name indicates, the chemical structures of furanocoumarins comprise a furan ring combined with coumarin1. The furan may bind in a variety of ways producing different isomers, many of which are reactive to DNA2.

Direct acute toxic effects of the plants with furanocoumarins are apparent and therefore have always been known. A touch of the sap of the plants containing these substances causes painful inflammation of the skin and its long-lasting irritating sensitivity to sunlight. If ingested, furanocoumarins can cause liver damage and death3.

Structure of the furanocoumarin isomer Psoralen. Click image for interactive 3D model 

Wild plants like Parsnip or the Giant Hogweed (in the image) contain these compounds as products of their secondary metabolism4,5. These plants effectively use them defending against a variety of lifeforms – from worms to ruminants and humans. As the species immediately deter animals, people have attempted cultivating them for the application of barriers such as, for example, to prevent grazing animals wandering over the boundaries of the pastures. This is not practiced nowadays as it can result in an uncontrolled spread of the plant species which are difficult to eradicate.

Cases of difficulties to control the spread of the Giant Hogweed are known in the Baltic States, Belarus, Poland, Ukraine and Russia. Far from being native to these countries, the plant was introduced in the mid. 20th century from Caucasus6. Since the attempts of manual cut off the plants can result in the skin burn, various herbicides are being used7 which have their own side effects, not least of which is their leaching to water.

SMILES of Psoralen (furanocoumarins isomer): O=C1/C=C\c2cc3ccoc3cc2O1

References:

  1. IUPAC, Compendium of Chemical Terminology, 2nd ed. (1997). Online corrected version:  (2006–) http://goldbook.iupac.org/html/F/F02562.html
  2. Musajo, L., Rodighiero, G., Dall'Acqua, F. Evidences of a photoreaction of the photosensitizing furocoumarins with DNA and with pyrimidine nucleosides and nucleotides. Celular and molecular life sciencess 1965: 21(1), p. 24–26
  3. Wayne, G.I. Toxicological significance of plant furocoumarins. Effects of Poisonous Plants on Livestock
    1978: p. 475-485
  4. Ceska, O., Chaudhary, S., Warrington, P., Poulton, G., Ashwood, M.S. Naturally-occurring crystals of photocarcinogenic furanocoumarins on the surface of parsnip roots sold as food. Experientia 1986: 42(11) p. 1302-1304
  5. Niinikoski, P., Korpelainen, H. Population genetics of the invasive giant hogweed (Heracleum sp.) in a northern European region. Plant Ecology 2015: 216(8) p. 1155-1162.
  6. ["Stalin's Revenge" spreads not just in Poland and the Baltic States"] Belarusian regional news (in Russian). 2009-05-09. Retrieved 2018-09-20.
  7. ["Battle against Heracleum"] Delfi Science (in Lithuanian). 2008-05-21. Retrieved 2018-09-20.

Sources of images:

  1.  http://mvitalijus.blogspot.com
  2. https://owlcation.com
  3. www.delfi.lt