Coumarins of different kinds are found in many plant species and have widely divergent actions. Their activities can include anti-inflammatory, antispasmodic, anti-edematous, and vascular tonic effects.

There are 700+ plant coumarins derived from the plant compound coumarin which occurs widely in plants, usually in bound form. Coumarin has been found in 150 plant species in more than 20 families and has anti-hemorrhagic effects and for this reason is used as rat poison (!). In addition it has anti-fungal and anti-tumor properties.

Note: Coumarins do inhibit platelet-aggregation but are relatively weak compared to coumarin. Also coumarin is virtually devoid of anticoagulant effects in humans because a structurally essential characteristic for the anticoagulant potential of coumarin derivatives is absent. (The drug Warfarin is a synthetic chemical derived from coumarol). Although coumarin has little-no- anticoagulant activity, it is transformed to the natural anticoagulant dicoumarol by a number of species of fungi.

This procedes through production of 4-hydroxycoumarin, then further into the actual anticoagulant dicoumarol, a fermentation product and mycotoxin.

The 3 major classes of plant coumarins include:

  • Hydroxycoumarins
  • Furanocourmarins – such as bergapten in Apium graveolens (Celery seed) and khellin from Ammi visnaga (a powerful smooth muscle relaxant)
  • Pyranocourmarins

 Herbal examples:

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