scientific name: Tabebuia impetiginosa other common names: Lapachol, lapacho, trumpet bush growing areas: Native to South and Central America
physical description: It is a large flowering evergreen tree that can grow up to 15 feet high. The tree produces a large pink flower. The tree's durable wood has made it a target of loggers in the Amazon area, according to concerned environmentalists. There has also been concern raised over the harvesting of the tree's inner bark to produce folk medicine.
traditional uses: Pau d'arco's history.as a medicinal plant has been controversial. In folk m/dicine, lapachol is obtained from the inner bark of the tree and has been used in Latin America for the treatment of colds, flu, arthritis, rheumatism, syphilis, and cancer. It also has been used to treat disorders of the immune system such as psoriasis. Because of pau d'arco's traditional use to treat cancer in some cultures, it has received a great deal of attention and publicity as a possible cure. But despite great fanfare, testing of the extracts from the plant have, according to a number of experts and government officials, not supported the use of lapachol as a treatment for cancer. AIDS patients have also turned to pau d'arco as an alternative treatment, most likely because it has a reputation as a remedy for immune system problems.
availability and dosage: Pau d'arco is available in capsules, tablets, extracts, and teas. The bark is sold as a powder. Dosages may vary and run from 1 to 4 capsules a day for a week. Some suppliers recommend 300 milligrams of powdered bark three times a day. A tea is also made by boiling the bark in water for eight to ten minutes.
contraindications: Pau d'arco contains substances that researchers believe can cause problems with coagulation, which makes use of the plant questionable for people suffering from coagulation disorders or taking anticoagulants. Experts also say pregnant and breastfeeding women should avoid the herb.
special precautions: Consult your physician before beginning any use of an ethnobotanical substance for medicinal purposes. Certain substances in pau d'arco present a danger of toxicity in humans. Fetrow and Avila recommend that pau d'arco not be used because of the problem of toxicity.
medical research: During the 1960s, after it gained a reputation as a folk treatment for cancer, lapachol was put into clinical trials by the National Cancer Institute. However, in 1974 it was reportedly dropped by the NCI after failing to produce. significant results that outweighed its serious side effects. The negative experience of the NCI apparently did not forestall others from experimenting with lapachol as a cancer therapy, and there have been reports of trials in other countries that have shown beneficial results.
While cancer experiments in the United States did not go well, lapachol seemed to fare better with experiments aimed at testing its usefulness as an antipsoriatic and anti-inflammatory agent. In an experiment in Brazil, lapachol was found to have significant anti-inflammatory action, diminishing swelling in rodents by as much as 85 percent, depending on the dosage. Results of another experiment published in 1999 showed that lapachol compounds stopped the growth of human keratinocytes, the cells involved in psoriasis.