Pau d'arco

(Tabebuia impetiginosa)

Family: Bignoniaceae
Genus: Tabebuia
Species: impetiginosa
Synonyms: Tabebuia avellanedae, T. ipe, T. nicaraguensis, T. schunkeuigoi, T. serratifolia, T. altissima, T. palmeri, Gelseminum avellanedae, Handroanthus avellanedae, H. impetiginosus, Tecoma adenophylla, Tecoma avellanedae, Tecoma eximia, Tecoma impetiginosa, Tecoma integra, Tecoma ipe
Common Names: Pau d’arco, ipê, ipê roxo, lapacho, tahuari, taheebo, trumpet tree, ipê-contra-sarna, tabebuia ipê, tajy
Phytochemicals: Aluminum, Anthraquinones, Ascorbic-acid, Ash, Beta-carotene, Beta-sitosterol, Calcium, Carbohydrates, Chromium, Chrysophanic-acid, Cobalt, Dehydro-alpha-lapachone, Dehydroisolapachone, Dehydrotectol, Fat, Fiber, Iron, Lapachol, Magnesium, Manganese, Naphthoquinones, Niacin, Phosphorus, Potassium, Protein, Riboflavin, Selenium, Silicon, Sodium, Thiamin, Tin, Zinc
Part Used: Bark, wood

HERBAL PROPERTIES AND ACTIONS

Main Actions: kills bacteria kills fungi kills leukemia cells kills viruses relieves pain reduces inflammation kills parasites fights free radicals reduces tumors

Other Actions: thins blood inhances immunity mildly laxative relieves rheumatism dries secretions

Standard Dosage: Bark, Heartwood. Decoction: 1/2 cup 2-4 times daily; Tincture: 2-3 ml 2-3 times daily; Capsules: Not recommended

Pau d’arco is a huge canopy tree native to the Amazon rainforest and other tropical parts of South and Latin America. It grows to 30 m high and the base of the tree can be 2–3 m in diameter. The tree also is popular with timber loggers—its high-quality wood is some of the heaviest, most durable wood in the tropics. Pau d’arco wood is widely used in the construction of everything from houses and boats to farm tools. The common name pau d’arco (as well as its other main names of commerce, ipê roxo and lapacho) is used for several different species of Tabebuia trees that are used interchangeably in herbal medicine systems. T. impetiginosa is known for its attractive purple flowers and often is called “purple lapacho.” It has been the preferred species employed in herbal medicine. It is often referred to by its other botanical name, Tabebuia avellanedae; both refer to the same tree. Other pau d’arco species produce pink (T. heptaphylla), yellow (T. serratifolia and T. chrysantha) or white (T. bahamensis) flowers. Though many of these species may have a similar phytochemical makeup, they are different species of trees.

The chemical constituents and active ingredients of pau d'arco have been well documented. Its use with (and reported cures for) various types of cancers fueled much of the early research in the early 1960s. The plant contains a large amount of chemicals known as quinoids, and a small quantity of benzenoids and flavonoids. These quinoids (and, chiefly, anthraquinones, furanonaphthoquinones, lapachones, and naphthoquinones) have shown the most documented biological activity and are seen to be the center of the plant's efficacy as an herbal remedy. In the 1960s, plant extracts of the heartwood and bark demonstrated marked antitumorous effects in animals, which drew the interest of the National Cancer Institute (NCI). Researchers decided that the most potent single chemical for this activity was a naphthoquinone chemical named lapachol and they concentrated solely on this single chemical in their subsequent cancer research. In a 1968 study, lapachol demonstrated highly significant activity against cancerous tumors in rats.

By 1970, NCI-backed research already was testing lapachol in human cancer patients. The institute reported, however, that their first Phase I study failed to produce a therapeutic effect without side-effects - and they discontinued further cancer research shortly thereafter. These side-effects were nausea and vomiting (very common with chemotherapy drugs) and anti-vitamin K activity (the main concerns over which caused anemia and an anticoagulation effect). Interestingly, other chemicals in the whole plant extract (which, initially, showed positive antitumor effects and very low toxicity) demonstrated positive effects on vitamin K and, conceivably, compensated for lapachol's negative effect. Despite NCI's abandonment of the research, another group developed a lapachol analog (which was patentable) in 1975. One study reported that this lapachol analog increased the life span of mice inoculated with leukemic cells by over 80%. In a small, uncontrolled, 1980 study of nine human patients with various cancers (liver, kidney, breast, prostate, and cervix), pure lapachol was reported to shrink tumors and reduce pain caused by them - and three of the patients realized complete remissions.

The phytochemical database housed at the U.S. Department of Agriculture has documented lapachol as being antiabscess, anticarcinomic, antiedemic, anti-inflammatory, antimalarial, antiseptic, antitumorous, antiviral, bactericidal, fungicidal, insectifugal, pesticidal, protisticidal, respiratory depressant, schistosomicidal, termiticidal, and viricidal. It's not surprising that pau d'arco's beneficial effects were seen to stem from its lapachol content. But another chemical in pau d'arco, beta-lapachone, has been studied closely of late-and a number of recent patents have been filed on it. It has demonstrated in laboratory studies to have activities similar to lapachol (antimicrobial, antifungal, antiviral, antitumorous, antileukemic, and anti-inflammatory), with few side-effects. In one of these studies on beta-lapachone and other quinones in pau d'arco, researchers reported: "Because of their potent activity against the growth of human keratinocytes, some lapachol-derived compounds appear to be promising as effective antipsoriatic agents." In a 2002 U.S. patent, beta-lapachone was cited to have significant anticancerous activity against human cancer cell lines including: promyelocytic leukemia, prostate, malignant glioma, colon, hepatoma, breast, ovarian, pancreatic, multiple myeloma cell lines and drug-resistant cell lines. In yet another U.S. patent, beta-lapachone was cited with the in vivo ability to inhibit the growth of prostate tumors.

In addition to its reported antitumor and antileukemic activities, pau d'arco clearly has demonstrated broad spectrum actions against a number of disease-causing microorganisms, which supports its wide array of uses in herbal medicine. Antimicrobial properties of many of pau d'arco's active phytochemicals were demonstrated in several clinical studies, in which they exhibited strong in vitro activity against bacteria, fungi, and yeast (including Candida, Aspergillus, Staphylococcus, Streptococcus, Helicobacter pylori, Brucella, tuberculosis, pneumonia, and dysentery). In addition to its isolated chemicals, a hot water extract of pau d'arco demonstrated antibacterial actions against Staphylococcus aureus, Helicobacter pylori (the bacteria that commonly causes stomach ulcers), and Brucella. A water extract of pau d'arco was reported (in other in vitro clinical research) to have strong activity against 11 fungus and yeast strains. Pau d'arco and its chemicals also have demonstrated in vitro antiviral properties against various viruses, including Herpes I and II, influenza, polio virus, and vesicular stomatitis virus. Its antiparasitic actions against various parasites (including malaria, schistosoma, and trypanosoma) have been confirmed as well. Finally, bark extracts of pau d'arco have demonstrated anti-inflammatory activity and have shown success against a wide range of induced inflammation in mice and rats.

Pau d'arco has a long and well-documented history of use by the indigenous peoples of the rainforest. Indications imply that its use may actually predate the Incas. Throughout South America, tribes living thousands of miles apart have employed it for the same medicinal purposes for hundreds of years. Several Indian tribes of the rainforest have used pau d'arco wood for centuries to make their hunting bows; their common names for the tree mean "bow stick" and "bow stem." The Guarani and Tupi Indians call the tree tajy, which means "to have strength and vigor." They use the bark to treat many different conditions and as a tonic for the same strength and vigor it puts into their bows. Pau d'arco is recorded to be used by forest inhabitants throughout the Amazon for malaria, anemia, colitis, respiratory problems, colds, cough, flu, fungal infections, fever, arthritis and rheumatism, snakebite, poor circulation, boils, syphilis, and cancer.

Pau d’arco is an important resource from the rainforest with many applications in herbal medicine. Unfortunately, its popularity and use have been controversial due to varying results obtained with its use. For the most part, these seem to have been caused by a lack of quality control—and confusion as to which part of the plant to use and how to prepare it. Many species of Tabebuia, as well as other completely unrelated tree species exported today from South America as “pau d’arco,” have few to none of the active constituents of the true medicinal species.

Most of the commercially-available products, though, contain the inner and outer bark of the tree—which is stripped off at sawmills when the heartwood is milled into lumber for construction materials. Finally, many consumers and practitioners are unaware that, for the best results when extracting these particular active chemicals (even after obtaining the correct species), the bark and/or wood must be boiled at least 8–10 minutes—rather than brewed as a simple tea or infusion (lapachol and the other quinoids are not very water soluble).

Following-up a brief summary of worldwide ethnomedical uses of pau d'arco.

Region	Uses
Amazonia	for colds, cough, fever, flu, leishmaniasis, sores, urinary tract infections
Argentina	for diarrhea, respiratory infections, urinary tract infections
Bahamas	for backaches, gonorrhea, incontinence, toothache, urinary disorders
Brazil	for allergies, arthritis, asthma, athlete's foot, bacterial infections, bed-wetting, blood builder, boils, bursitis, cancer, cancer pain, candida, circulation (poor), colds, colitis, constipation, cystitis, diabetes, dysentery, eczema, fever, flu, fungal infections, gastritis, gingivitis, gonorrhea, hernia, hemorrhoid, hemorrhages, herpes, Hodgkin's disease, immune disorders, impetigo, inflammation, itch, leishmaniasis, leukemia, liver disorders, malaria, parasites, prostatitis, psoriasis, respiratory problems, rheumatism, ringworm, scabies, skin problems, snakebite, sore throat, stomatitis, stomach problems, syphilis, throat (sore), tendonitis, ulcers, urinary tract infections, uterine disorders, vaginal discharge, varicose veins, warts, wounds, and as a astringent, diuretic, pain-reliever and tonic
Costa Rica	for cancer, colds, fever, headaches, snakebites
Mexico	for anemia, fever
South America	for allergies, anemia, arthritis, bacterial infections, boils, cancer, candida, circulation problems, colitis, colds, constipation, cough, cystitis, diabetes, diarrhea, dysentery, fever, flu, fungal infections, gastritis, gastrointestinal problems, inflammation, malaria, pharyngitis, prostatitis, respiratory diseases, snakebites, syphilis, ulcers, urinary disorders
United States	for allergies, anti-inflammatory, arthritis, bacterial infections, boils, cancer, candida, circulation disturbances, colds, constipation, diabetes, dysentery, fevers, flu, fungal infections, gastrointestinal problems, Hodgkin's disease, inflammation, leukemia, liver disease, lupus, osteomyelitis, parasites, Parkinson's disease, prostatitis, psoriasis, respiratory problems, skin ulcerations, syphilis, ulcers, urinary tract infections, viral infections, warts, and as a pain-reliever, and antioxidant

PAU D'ARCO PLANT SUMMARY

Main Preparation Method:	tincture or decoction
Main Actions (in order):	anticandidal, antifungal, antiviral, antibacterial, anticancerous
Main Uses:	for Candida, yeast, and other fungal infections (taken internally and used as a douche or topically). for leukemia and cancer for colds, flu, and other upper-respiratory bacterial and viral infections for sexually transmitted diseases (syphilis, gonorrhea, etc.) for psoriasis and dermatitis
Properties/Actions Documented by Research:	analgesic (pain-reliever), antibacterial, anticancerous, anticandidal, antifungal, anti-inflammatory, antileukemic, antimalarial, antiparasitic, antitumorous, antiviral, insecticidal
Other Properties/Actions Documented by Traditional Use:	anti-allergy, antiulcerous , anticoagulant (blood thinner), antidysenteric, antioxidant, anti-rheumatic, antivenin, astringent, cardiotonic (tones, balances, strengthens the heart), hepatotonic (tones, balances, strengthens the liver), immunostimulant, laxative
Traditional Preparation:	One-half to one cup bark and/or heartwood decoction taken orally 2-4 times daily. (Do not prepare an infusion/tea for this plant-it will not be as effective.) This decoction also is employed traditionally as a douche for yeast infections (use once daily for three consecutive days) and is used topically on the skin for skin fungi (such as nail fungus and athlete's foot).
Contraindications:	There have been no reports in the literature of contraindications when a whole-bark decoction or tincture is used. However: At least one isolated phytochemical in pau d’arco (lapachol) has demonstrated abortifacient properties in studies. As there are no studies confirming the safety of traditional bark decoctions used by pregnant women (nor is there indication in traditional medicine systems using this plant during pregnancy), the use of pau d’arco during pregnancy is not recommended. Large single dosages of pau d’arco decoctions (more than one cup) may cause gastrointestinal upset and/or nausea. Do not use in high doses unless under the advice of a qualified health practitioner; reduce dosage if nausea occurs.
Drug Interactions:	None reported.

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