ingredient information
Pau D'Arco Bark
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 Tabebuia genus includes about 100 species of large, flowering trees that are common to South American cities’ landscapes for their beauty. 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. TRIBAL AND HERBAL MEDICINE USES 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 also has a long history in herbal medicine around the world. In South American herbal medicine, it is considered to be astringent, anti-inflammatory, antibacterial, antifungal, and laxative; it is used to treat ulcers, syphilis, urinary tract infections, gastrointestinal problems, candida and yeast infections, cancer, diabetes, prostatitis, constipation, and allergies. It is used in Brazilian herbal medicine for many conditions including cancer, leukemia, ulcers, diabetes, candida, rheumatism, arthritis, prostatitis, dysentery, stomatitis, and boils. In North American herbal medicine, pau d'arco is considered to be analgesic, antioxidant, antiparasitic, antimicrobial, antifungal, antiviral, antibacterial, anti-inflammatory, and laxative, as well as to have anticancerous properties. It is used for fevers, infections, colds, flu, syphilis, urinary tract infections, cancer, respiratory problems, skin ulcerations, boils, dysentery, gastrointestinal problems of all kinds, arthritis, prostatitis, and circulation disturbances. Pau d'arco also is employed in herbal medicine systems in the United States for lupus, diabetes, ulcers, leukemia, allergies, liver disease, Hodgkin's disease, osteomyelitis, Parkinson's disease, and psoriasis, and is a popular natural remedy for candida and yeast infections. The recorded uses in European herbal medicine systems reveal that it is used in much the same way as in the United States, and for the same conditions. PLANT CHEMICALS 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. Once again, instead of pursuing research on a complex combination of at least 20 active chemicals in a whole plant extract (several of which had antitumor effects and other positive biological activities), research focused on a single, patentable chemical-and it didn't work as well. 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. The main plant chemicals in pau d'arco include: acetaldehydes, alpha-lapachone, ajugols, anisic acid, anthraquinones, benzoic acids, benzenes, beta-lapachone, carboxaldehydes, chromium, chrysanthemin, dehydro-alpha-lapachone, dehydroisolapachone, deoxylapachol, flavonoids,furanonaphthoquinones, hydrochlorolapachol, 2-hydroxy-3-methyl-quinone, 6-hydroxy-mellein, iso-8-hydroxy-lariciresinol, kigelinone, lapachenol, lapachenole, lapachol, lapachones, menaquinones, 4-methoxyphenol, naphthoquinones, paeonidin-3-cinnamyl-sophoroside, phthiolol, quercetin, tabebuin, tectoquinone, vanillic acid, vanillin, veratric acid, veratric aldehyde, and xyloidone. BIOLOGICAL ACTIVITIES AND CLINICAL RESEARCH 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. CURRENT PRACTICAL USES 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. Pau d’arco lumber is in high demand in South America. The inner bark shavings commonly sold in the U.S. are actually by-products of the timber and lumber industries. Even mahogany shavings from the same sawmill floors in Brazil are swept up and sold around the world as “pau d’arco� (due to the similarity in color and odor of the two woods). In 1987, a chemical analysis of 12 commercially-available pau d’arco products revealed only one product containing lapachol—and only in trace amounts. As lapachol concentration typically is 2–7% in true pau d’arco, the study surmised that the products were not truly pau d’arco, or that processing and transportation had damaged them. Most pau d’arco research has centered on the heartwood of the tree. 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. Additionally, at least 10 species of Tabebuia are logged commercially in South America for lumber purposes alone. When these logs arrive at lumber mills, the identifying leaves and flowers (which distinguish the tree species) are long gone—it’s all just “pau d’arco.� This may explain varying species of pau d’arco bark being sold as herbal products—and their resulting (diminished) quality. 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). Source: