Piscidia erythrina is indigenous to Central America, Florida, and the West Indies, and is now found in Texas, Mexico, and the northern part of South America. Piscidia erythrina and Piscidia piscipula are generally considered synonyms for the same species. Piscidia erythrina provides a valuable source of charcoal and wood for building boats. The roots, pounded leaves, and branches of this plant have traditionally been employed in fish poisons (piscicides). Jamaica dogwood, or the dried root bark, is used medicinally to treat a variety of ailments.

In Belize, a decoction made from the bark of the Jamaica dogwood tree is taken internally for dysentery, diarrhea, and dysmennorhea (painful menstruation). Bark decoctions are known to have astringent action. Belizeans use them as a mouthwash for bleeding gums, and as an external wash for wounds, rashes, and other skin problems.

However, Jamaica dogwood is best known as a traditional remedy for treating neuralgia, menstrual pain, migraine, insomnia, and nervous tension. As early as 1844, Western scientists discovered that Jamaica dogwood had narcotic, analgesic, and sudorific (sweat-promoting) properties. Recent pharmacological studies have shown unequivocally that bark extracts of this plant produce sedative and narcotic effects in animals. Scientific findings such as these have helped to substantiate many of the traditional uses of this species.

Although Jamaica dogwood is an effective herbal remedy, it is also known to have potentially adverse side effects. Experts stress that Jamaica dogwood should be cautiously administered only by trained and qualified health care practitioners who understand the pharmacology, toxicology, and proper herbal preparation of this plant.

Jamaica dogwood has a foliage similar to that of Lonchocarpus. Its characteristic pods bear four projecting longitudinal wings. The bark is yellow or grayish brown on the outer surface, and either lighter colored or white on the inner surface. If the bark becomes damp, the inner surface turns to a peculiar shade of blue. The inner texture of the bark is quite fibrous. Its distinctly acrid and bitter taste causes a burning sensation in the mouth. The bark also gives off a noticeably unpleasant odor similar to that of broken opium.

Part Used/Pharmaceutical Designation

• Root bark (dried)
• Stem bark

• Acids: piscidic acid (p-hydroxybenzyltartaric) plus its mono and diethyl esters, fukiic acid and its 3'-O-methyl derivative; malic acid, succinic acid, tartaric acid.
• Isoflavonoids of varied structure: include ichthynone, jamaicin, piscerythrone, piscidone; milletone, isomilletone, dehydromilletone, rotenone, sumatrol (a rotenoid), lisetin (coumaronochrome)
• Glycosides: piscidin (crystallizable substance that is reportedly a mixture of two compounds), saponin glycoside (unidentified)
• Other constituents: alkaloid (unidentified, present in stem), resin, volatile oil (0.01%), beta-sitosterol, tannin (unspecified)

The bark is sold commercially in quilled pieces about one to two inches in length and 1/8 inch in thickness. However, there is considerable variation in the chemical constituents of Jamaica dogwood from different geographical regions. For example, chemical analysis of root bark material from Mexico revealed the presence of certain active principles (1% piscidone, 0.8% piscerythrone, 0.8% erythbigenin, 0.6% ichthynone, and 0.5% rotenone), but a total lack of jamaicin and only a minute quantity of lisetin. Jamaicin and lisetin are chief active principles in the bark from trees grown in Jamaica. This suggests that there may be chemical races (chemotaxonomic subspecies) of Jamaica dogwood. The geographical origin of bark material from Piscidia erythrina should thus be authenticated to ensure that it contains a maximal quantity of all active constituents, including jamaicin and lisetin.

Traditional uses: neuralgia, nervous debility, insomnia accompanying neuralgia; migraine, dysmenorrhea, violent toothache, whooping-cough, antispasmodic for asthma, dysmenorrhea, agent for dilating the pupil, piscicide, anodyne (analgesic), cardiotonic, diuretic, sedative, spasm

Conditions: sedative and narcotic actions for treating neuralgia, nervous debility, insomnia, migraine, dysmenorrhea

Clinical applications: sleep disorders (e.g., insomnia), neuralgia, dysmenorrhea, migraine, sedative, antitussive, spasmolytic, anti-inflammatory

In several in vivo pharmacological studies, bark extracts of Jamaica dogwood showed sedative, antitussive, antispasmodic, antipyretic, anti-inflammatory, hypotensive, and weak cannabinoid activity. In a comparative investigation of vegetable extracts on CNS activity in the mouse, oral dosing of Piscidia erythrina produced pharmacological effects intermediate between the sedative action of Valeriana officinalis and the anxiolytic (anti-anxiety) activity of Passiflora incarnata. In another study, Piscidia piscipula was one of several plants used in Guatemalan traditional medicine that elicited in vitro inhibition of dermatophytoses (microbial agents causing skin infections), including fungal pathogens.

Rotenone is an isoflavone isolated from the wood of Jamaica dogwood. It is one of the piscicidal constituents of the bark of this plant. Although rotenone is virtually nontoxic to warm-blooded animals, it is reportedly carcinogenic. However, in other research, rotenone exhibited anticancer action against lymphocytic leukemia and human epidermoid carcinoma of the nasopharynx.

Rotenone is also presumably responsible for the antispasmodic activity of Jamaica dogwood on uterine smooth muscle. Both in vitro and in vivo findings reveal that the antispasmodic properties of Jamaica dogwood bark extract are either equal to or, in some cases, even greater than those of papaverine.

• Dried root bark: 0.5 to 2 g (or equivalent in decoction) tid
• Fluid extract: (1:1 in 30% alcohol): 1 to 2 ml tid; or 2 to 8 ml per day (1:1, 60% ethanol)
• Tincture (1:5 in 45% ethanol): 5 to 30 drops (1 to 2 ml) tid

Jamaica dogwood is known to have irritant and toxic effects in humans. Overdosing with this plant can produce adverse symptoms such as numbness, tremors, salivation, and sweating.

In one study, Jamaica dogwood extract was toxic to rats and rabbits when given parenterally but nontoxic when administered orally. The test animals in this study were able to tolerate oral doses greater than 90 g dried extract/kg. An unidentified saponin isolated from the bark and administered intravenously to mice showed a LD₅₀ of 75 g/kg b.w.

Although Jamaica dogwood shows low toxicity in some animal species, it can have irritant and toxic effects in humans. In some human subjects, Jamaica dogwood reportedly produces adverse side effects of gastric distress and nausea. In both in vitro and in vivo studies, extracts of this plant were shown to have potential depressant activity. Jamaica dogwood should be administered only by qualified health care practitioners, and excessive use should be avoided. Under no circumstances should this plant be used during pregnancy and lactation.

No clinically significant interactions between Jamaica dogwood and conventional medications are known to have been reported in the literature to date.

In the United Kingdom, Jamaica dogwood is listed as a licensed product in Schedule 1, Table A of the General Sale List (GSL). The Council of Europe does not approve of Jamaica dogwood as a natural food flavoring because of its potential toxicity to humans. Powdered Jamaica dogwood is listed in the British Herbal Pharmacopeia as complying with requirements for identification and quantitative standards. The herb has not been approved by the German Commission E.

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