coumarin
Meaning of coumarin: The smell of new-mown hay and tonka beans, and the plant chemical that mold converted into the first true blood thinner.
Definition of coumarin
Coumarin is a sweet-smelling compound made by many plants, among them tonka beans, sweet clover, cassia cinnamon and sweet woodruff. It gives freshly cut hay its scent and is widely used in perfumery. Coumarin itself does not thin the blood, but its chemical skeleton is the frame on which the coumarin anticoagulants, warfarin among them, were later built.
Does coumarin thin the blood?
No, and the confusion is old and persistent. The story begins with cattle that bled to death after eating spoiled sweet clover hay. Mold growing in the damp hay had converted the harmless coumarin into a different compound, dicoumarol, which does block the recycling of vitamin K and so starves the body of the clotting factors that depend on it. Isolating dicoumarol led to a more potent relative, warfarin, first sold as rat poison and later as a medicine. The whole family is named for the plant compound it descends from, which is how an inert fragrance ended up sharing a name with an anticoagulant class.
Where is it found?
| Source | Note |
|---|---|
| Tonka bean | The original source, and the richest |
| Cassia cinnamon | The common supermarket type, far higher than Ceylon cinnamon |
| Sweet clover | The hay whose spoilage poisoned cattle |
| Sweet woodruff | Traditionally used to flavor drinks in central Europe |
Why is it limited in food?
Because of the liver, not the blood. Coumarin causes liver injury in rodents, and a minority of people appear to break it down along a route that produces a damaging by-product, so raised liver enzymes and occasional hepatitis have followed sustained intake. It is barred as a directly added flavoring in some countries and capped in others, and food agencies have issued advice about heavy daily use of cassia cinnamon for that reason. A preparation of coumarin was once promoted for the swelling of lymphedema, and liver toxicity in a proportion of takers ended that use. Its name is also close enough to the warfarin brand Coumadin to invite mix-ups between a fragrance compound and a potent anticoagulant.
Also known as
Used in a sentence
The flavoring was analyzed for coumarin content.
Good to know
Coumarin has no meaningful anticoagulant action of its own; the blood-thinning drugs named after it derive from dicoumarol, a mold product formed from it, and the toxicity attached to coumarin itself concerns the liver.