Common Trade Names
Tonka bean is difficult to obtain commercially; availability is rare.
Active components are extracted from the fruits and seeds of Dipteryx odorata, a tree that is native to South America, specifically Brazil and Venezuela. The tonka bean tree belongs to the legume family.
The primary chemical components of tonka bean are coumarin, dihydrocoumarin, and o-coumaric acid. Other components include melilotic acid, methyl melilotate, ethyl melilotate, 5-hydroxymethylfurfural, fat, and starch.
Coumarin is metabolized within the body to 7-hydroxycoumarin, which then undergo glucuronidation in the intestines and liver; this intensive first-pass metabolism results in a low absolute bioavailability of coumarin. Both coumarin and 7-hydroxycoumarin have inhibited growth of selected types of malignant human cell lines in vitro. The glucuronide metabolite of 7 -hydroxycoumarin appears to be inactive.
Tonka bean is claimed to relieve abdominal cramps and nausea; the fruit is also thought to act as an aphrodisiac. It is known as a folk remedy for whooping cough as well. Coumarin has long been used as a flavoring agent in foods and a scent in pharmaceutical products. It has shown therapeutic benefit against lymphmedema in clinical trials.
The usual dose used is 60 mg of coumarin PO daily. (Some studies have based doses on the coumarin content of the product.)
CV: potential cardiac effects (with large doses).
Anticoagulants: May cause excessive bleeding. Avoid administration with tonka bean.
Drugs that cause hepatotoxicity: Risk of additive toxicity. Avoid administration with tonka bean.
Contraindications and Precautions
Tonka bean is contraindicated in patients with under hepatic dysfunction due to the potential for toxicity. Avoid its use in pregnant or breast-feeding patients; effects are unknown.
Inform the patient that tonka bean is on the FDA's list of unsafe herbs.
Advise the patient to consult a health care provider before using herbal preparations because a treatment that has been clinically researched and proven effective may be available.
Monitor liver function test results.
Advise women to avoid using tonka bean during pregnancy or when breastfeeding-feeding.
Points of Interest
Do not confuse this herb with the synthetic anticoagulant bishydroxycoumarin.
Extracts of tonka bean have been used as a flavoring for castor oil preparations.
Several tonka bean components, especialIy coumarin and 7-hydroxycoumarin, show promise as future therapeutic agents. Because efficiency and safety data are lacking, the herb can not be recommended for any medicinal use.