Coumarin

Description

Coumarin is a naturally occurring Benzopyrone compound. It is found in a large number of plants belonging to many different families including tonka beans, woodruff, lavender oil, cassia, melilot (sweet clover), and other plants. It is found in edible plants such as strawberries, cinnamon, peppermint, green tea, carrots, and celery, as well as in partially fermented tea, red wine, beer, and other foodstuffs. Concentrations range from 87 000 ppm in cassia and 40 000 ppm in cinnamon to 20 ppm in peppermint and 5 ppb in tangerines.

Description

Coumarin is a benzopyrone that occurs naturally in plant-derived sources such as tonka beans, lavender oil, woodruff, and sweet clover. Its sweet scent makes it useful in perfume manufacture. It is a potent rodenticide, but it is only moderately toxic to humans. It is used to make warfarin, another rodenticide that is also a widely used anticoagulant drug (trade name Coumadin) for preventing thrombosis and embolism.

Chemical properties

WHITE CRYSTALS OR CRYSTALLINE POWDER

Chemical properties

Coumarin occurs widely in nature and determines, for example, the odor of woodruff. It forms white crystals (mp 70.6°C) with a hay-like, spicy odor. When treated with dilute alkali, coumarin is hydrolyzed to the corresponding coumarinic acid salt [(Z)-2-hydroxycinnamic acid]. Heating with concentrated alkali or with sodium ethanolate in ethanol results in the formation of o-coumaric acid salts [(E)-2-hydroxycinnamic acid]. 3,4-Dihydrocoumarin is obtained by catalytic hydrogenation, for example, with Raney nickel as a catalyst; octahydrocoumarin is obtained if hydrogenation is carried out at high temperature (200–250°C).

Chemical properties

Coumarin has a sweet, fresh, hay-like, odor similar to vanilla seeds, and a burning taste with bitter undertone and nutlike flavor on dilution.

Occurrence

Found in many plants and essential oils such as cassia, melilot, orchid, lavender and balsam of Peru (Sp?th, 1937; Gildemeister & Hoffman, 1966).

The Uses of Coumarin

coumarin is considered a blood thinner, it can also increase blood flow. Some sources cite anti-oxidant capacities, as well. It is a specific plant constituent and is what creates the fragrance of freshly mowed hay. Coumarin is found in such plants as cherries, lavender, licorice, and sweet clover.

The Uses of Coumarin

Pharmaceutic aid (flavor). Found in tonka beans, levender oil, woodruff, sweet clover.

The Uses of Coumarin

antineoplastic, antiinflammatory, antihyperglycaemic

What are the applications of Application

Coumarin is an anticoagulant agent found in certain plants

Definition

ChEBI: A chromenone having the keto group located at the 2-position.

Definition

A colorless crystalline compound with a pleasant odor, used in making perfumes. On hydrolysis with sodium hydroxide it forms coumarinic acid.

Preparation

Coumarin is currently produced by Perkin synthesis from salicylaldehyde. In the presence of sodium acetate, salicylaldehyde reacts with acetic anhydride to produce coumarin and acetic acid. The reaction is carried out in the liquid phase at elevated temperature.
A process for the production of coumarin from hexahydrocoumarin by dehydrogenation has also been elaborated.
Since the odor of coumarin is relatively weak, strong-smelling by-products (e.g., vinylphenol) must be removed. Many purification methods have been reported and patented.

Aroma threshold values

Detection at 34 to 50 ppb; recognition, 250 ppb

Synthesis Reference(s)

The Journal of Organic Chemistry, 27, p. 4704, 1962 DOI: 10.1021/jo01059a541
Tetrahedron Letters, 27, p. 3911, 1986 DOI: 10.1016/S0040-4039(00)83914-3

General Description

Colorless crystals, flakes or colorless to white powder with a pleasant fragrant vanilla odor and a bitter aromatic burning taste.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

Coumarin is sensitive to exposure to light. Coumarin is also sensitive to heat. Coumarin is incompatible with strong acids, strong bases and oxidizers. Coumarin is hydrolyzed by hot concentrated alkalis. Coumarin can be halogenated, nitrated and hydrogenated (in the presence of catalysts).

Hazard

Toxic by ingestion; carcinogenic. Use in food products prohibited (FDA). Questionable carcinogen.

Health Hazard

SYMPTOMS: Exposure to Coumarin may cause narcosis. It may also cause irritation and liver damage.

Fire Hazard

Coumarin is combustible.

Flammability and Explosibility

Non flammable

Biological Activity

Oral anticoagulants can be prepared from compounds with coumarin as a base. Coumarin has been known for well over a century and, in addition to its use pharmaceutically, it is also an excellent odor-enhancing agent. However, because of its toxicity, it is not permitted in food products in the United States (Food and Drug Administration). One commercial drug is 3-(alpha-acetonyl-4-nitrobenzyl)- 4-hydroxycoumarin. This drug reduces the concentration of prothrombin in the blood and increases the prothrombin time by inhibiting the formation of prothrombin in the liver. The drug also interferes with the production of factors VII, IX, and X, so that their concentration in the blood is lowered during therapy. The inhibition of prothrombin involves interference with the action of vitamin K, and it has been postulated that the drug competes with vitamin K for an enzyme essential for prothrombin synthesis. Another commercial drug is bis-hydroxy-coumarin, C19H12O6. The actions of this drug are similar to those just described.

Contact allergens

Coumarin is an aromatic lactone naturally occurring in Tonka beans and other plants. As a fragrance allergen, it has to be mentioned by name in cosmetics within the EU

Safety Profile

Poison by ingestion, intraperitoneal, and subcutaneous routes. Questionable carcinogen with experimental tumorigenic data. Experimental teratogenic effects. Mutation data reported. Combustible when exposed to heat or flame. When heated to decomposition it emits acrid smoke and fumes. See also KETONES and ANHYDRIDES.

Synthesis

May be extracted from tonka beans; from salicylaldehyde and acetic anhydride in the presence of sodium acetate; also from o-cresol and carbonyl chloride followed by chlorination of the carbonate and fusion with a mixture of alkali acetate, acetic anhydride and a catalyst.

Environmental Fate

Coumarin toxicity is a function of blood and target tissue levels of coumarin relative to the metabolic capacity of the target organ. Cellular toxicity results when the formation of the toxic moieties exceeds the capacity of the cell to detoxify. This can have significant impact when comparing dosing by gavage to dietary exposure.

Purification Methods

Coumarin crystallises from ethanol or water and sublimes in vacuo at 43o [Srinivasan & deLevie J Phys Chem 91 2904 1987]. [Beilstein 17/10 V 143.]

Toxicity evaluation

Coumarin is readily biodegradable. Coumarin is unlikely to bind to soil. Coumarin does not bioaccumulate; the bioconcentration factor has been determined to be <10–40. Various environmental fate studies have shown that coumarin in the environment would biodegrade and be lost to volatilization. Losses resulting from photolysis may also occur.