Coumarin derivatives are widely used in pharmaceutical and commercial applications due to their health properties. A compound found naturally in plants such as tonka beans, cinnamon, sweet clover, and vanilla grass, coumarin has several chemical derivatives that can be found naturally or synthesized in the laboratory. These include the naturally occurring umbelliferone, as well as the synthetic drugs warfarin and bishydroxycoumarin. Coumarin derivatives have been shown to possess anti-inflammatory and anticoagulant properties, but they can also be toxic in high amounts and are sometimes used as rodenticides.
Although coumarin itself does not function as an anticoagulant — a substance that prevents blood clotting — it can be chemically modified through natural or artificial processes to do so. The coumarin molecule is changed through the addition of certain chemical groups into a substance called 4-hydroxycoumarin, which can in turn be transformed into drugs with anticoagulant properties. Several different forms of 4-hydroxycoumarins exist.
The 4-hydroxycoumarin known as bishydroxycoumarin, or dicoumarol, can be formed through natural or artificial methods. When sweet clover interacts with fungi and becomes moldy, it undergoes a chemical change that causes the coumarin in the plant to transform into bishydroxycoumarin. The anticoagulant properties of coumarin derivatives such as dicoumarol were first discovered in 1939 from evidence that cattle in North America that had been fed with sweet clover were suffering from hemorrhaging, or bleeding. Bishydroxycoumarin was later produced synthetically for use as an oral anticoagulant.
Warfarin, a derivative of dicoumarol, is a popular synthetic drug used to prevent blood clots in cases where clot formation might cut off blood supply to an important organ such as the heart or brain. Before its development as an anticoagulant, this drug was commonly used as a rodenticide. Warfarin and other coumarin derivatives function as pesticides by causing uncontrolled hemorrhaging in the target animal.
The anticoagulant activity of coumarin derivatives can be toxic to humans if these compounds are ingested in excessive amounts. Vitamin K is a known antidote in cases where excessive ingestion has occurred. This is because substances such as dicoumarol function by inhibiting the action of Vitamin K in the production of prothrombin, an essential compound in the process of blood clotting. By adding Vitamin K, the anticoagulant action of dicoumarol can be counteracted.
Umbelliferone, unlike warfarin and other synthetic compounds, can be found naturally in certain fruits. It too has medicinal properties, including antioxidant activity. In other words, it can help prevent oxidation, a chemical reaction that may result in the destruction of cells. Umbelliferone is useful medically as an addition to sunscreen and as a starting point for synthesizing anti-cancer drugs.