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Furanocoumarins as potent chemical defenses
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| Furanocoumarins are toxic compounds found primarily in species of the Apiaceae and
Rutacea. They come in a variety of flavors and have adverse affects on wide variety
of organisms, ranging from bacteria to mammals. Some of the furanocoumarins are
photoactive--their toxicity is enhanced in the presence of ultraviolet radiation.
One of the better-studied modes of toxicity involves the binding of furanocoumarins to
DNA. However, furanocoumarins have also been shown to interact with protein and
lipids. |
 Biosynthesis involves contributions from two pathways, the
phenylpropanoid pathway and the mevalonic acid pathway. The immediate precursors for
furanocoumarin synthesis are umbelliferone and isoprene. Two categories of
furanocoumarins are produced; the linear furano- coumarins have the furan ring in line
with the benz-2-pyrone nucleus, while the angular furanocoumarins have the furan ring
oriented at an angle to the nucleus.
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 The furanocoumarins
found in wild parsnip are shown at left and play a dominant role in resistance of this
plant to its principal enemy the parsnip webworm (see coevolution).
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People, as well as insects, can suffer from exposure to these
compounds. "Celery picker's itch" and "bartender's itch" are
two maladies suffered when humans come into contact with furanocoumarin- containing celery
plants or the oil of lime peels. The symptoms are dramatic, as shown from our own
personal experiences below:
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 In the most severe cases, blisters will develop (top).
In less severe cases, the skin will become hyperpigmented and can remain so for several
weeks (left, bottom).
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last updated 6/14/2010
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