Paud’arco

August 26th, 2008

Botanical Name:pau d’arco
common names: Poui, trumpet trees and pau d’arco.
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
Part Used: Bark, wood
Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Subclass: Asteridae

Habitat: The species range from northern Mexico and the Antilles south to northern Argentina, including the Caribbean islands of Hispaniola (Dominican Republic and Haiti) and Cuba.

Description:
They are large shrubs and trees growing to 5 to 50 m (16 to 160 ft) tall depending on the species; many species are dry-season deciduous but some are evergreen. The leaves are opposite pairs, complex or palmately compound with 3-7 leaflets.

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Tabebuia is a notable flowering tree. The flowers are 3 to 11 cm (1 to 4 in) wide and are produced in dense clusters. They present a cupular calyx campanulate to tubular, truncate, bilabiate or 5-lobed. Corolla colors vary between species ranging from white, light pink, yellow, lavender, magenta, or red. The outside texture of the flower tube is either glabrous or pubescent.

The fruit is a dehiscent pod, 10 to 50 cm (4 to 20 in) long, containing numerous - in some species winged - seeds. These pods often remain on the tree through dry season until the beginning of the rainy season.

General Uses:
Species in this genus are important as timber trees. The wood is used for furniture, decking, and other outdoor uses. It has a fire rating of A1 (the highest possible, the same as concrete),and is denser than water (it sinks). It is increasingly popular as a decking material due to its insect resistance and durability. By 2007, FSC-certified ipê wood had become readily available on the market, although certificates are occasionally forged.

Tabebuia is widely used as ornamental tree in the tropics in landscaping gardens, public squares and boulevards due to its impressive and colorful flowering. Many flowers appear on still leafless stems at the end of the dry season, making the floral display more conspicuous. They are useful as honey plants for bees, and are popular with certain hummingbirds.Naturalist Madhaviah Krishnan on the other hand once famously took offense at ipé grown in India, where it is not native.

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.

Medicinal Uses:
The bark of several species has medical properties. The bark is dried, shredded and then boiled making a bitter or sour-tasting brownish-colored tea. Tea from the inner bark of Pink Ipê (T. impetiginosa) is known as Lapacho or Taheebo. Its main active principles are lapachol, quercetin and other flavonoids. It is also available in pill form. The herbal remedy is typically used during flu and cold season and for easing smoker’s cough. It apparently works as expectorant, by promoting the lungs to cough up and free deeply embedded mucus and contaminants. However, lapachol is rather toxic and therefore a more topical use e.g. as antibiotic or pesticide may be advisable. Other species with significant folk medical use are T. alba and Yellow Lapacho (T. serratifolia).

Tabebuia heteropoda, T. incana and other species are occasionally used as an additive to the entheogenic drink Ayahuasca.

Mycosphaerella tabebuiae, a plant pathogenic sac fungus, was first discovered on an ipê tree.

Herbal Properties:Kills bacteria, kills fungi,kills leukemia cells,kills viruses, relieves pain,reduces inflamations,kills parasites,fights free radicals,reduces tumors

Other Actions:Thins blood, enhances immunitu,mildly laxative,releves rheumatism,dries secretion

Standard Doses: Bark,Heartwood…1/2 cup 2 -4 times daily. Tinchure….2-3 ml 2-3 times daily

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).

It is therefore not surprising that consumers and practitioners are experiencing spotty results with commercially-available pau d’arco products. With its many effective applications, however, it would behoove consumers to take the time to learn about the available products and suppliers, and find a reliable source for this important medicinal plant from the rainforest. Relatively new in the marketplace are standardized extracts of pau d’arco (that guarantee the amount of lapachol and/or naphthoquinones). In such a product, it would be unclear if other active quinones have been extracted (and to what extent) in these chemically-altered products. Although the natural wood and bark are quite effective when the correct species is used and prepared properly, the new standardized extracts may be the safer (although more expensive) purchase for most laypersons and general consumers concerned about quality but which don’t have the time to research each product.

There have been no reports of human toxicity when a whole-bark decoction or tincture of pau d’arco is used. The oral LD50 dosage for lapachol is reported to be 1.2–2.4 g/kg (body weight) in rats and 487–621 mg/kg in mice. Good quality pau d’arco (Tabebuia impetiginosa) contains an average of 4% lapachol (or 40 mg of lapachol per gram of pau d’arco bark/wood).

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 animal 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.

Disclaimer:

The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplements, it is always advisable to consult with your own health care provider

Resources:
http://en.wikipedia.org/wiki/Tabebuia
http://www.umm.edu/altmed/articles/pau-darco-000268.htm
http://www.rain-tree.com/paudarco.htm