Tabebuia

Tabebuia is a genus that includes around seventy species of trees native to the intertropical zone of America, spread from Mexico and the Caribbean —where most of them are found. species—to north-central Argentina and Paraguay as well as southern Bolivia. In 1970 a new genus (Handroanthus) was created to house many of the Tabebuia species. It is the national tree of Paraguay, where it is called "tajy". The species Handroanthus chrysanthus has been the national tree of Venezuela since May 29, 1948 and is known as araguaney.

Description

They are emerging shrubs or trees. Leaves palmately foliate. Terminal inflorescence, often at the apex of a branch dichotomy, usually paniculate, often very showy, flowers white, yellow, lilac, purplish red, or red; calyx cupular, campanulate or tubular, truncated to bilabiate or slightly 5-lobed; corolla tubular-infundibuliform to tubular-campanulate (in Nicaragua), glabrous or puberulent on the outside; thecae straight, divaricate, glabrous; ovary linear-oblong; pulviniform disc. Capsule subterete, linear-elongated to short and oblong, dehiscence more or less perpendicular to the septum, surface smooth to irregularly wavy-muricate, glabrous to lepidote or stellate-pubescent; thin, 2-winged seeds. Deciduous foliage, its foliage is concentrated in the highest part of the crown. Green leaves, opposite and petiolate, slightly serrated leaflets, elliptical and lanceolate.

Biochemical components

Several categories of phytochemicals have been identified in the leaves, bark and wood of T. impetiginosa. From the bark of T. impetiginosa, 19 glycosides have been extracted (composed of four iridoid glycosides, two lignan glycosides, two isocoumarin glycosides, three phenylethanoid glycosides and eight phenolic glycosides).

The main components of T. impetiginosa are furanonaphthoquinones, naphthoquinones, anthraquinones (e.g., anthraquinone-2-carboxylic acid, quinones, benzoic acid, flavonoids, cyclopentene dialdehydes, coumarins, iridoids and phenolic glycosides. Lapachol and β-lapachone are the main naphthoquinones studied within the medical field.

According to the available scientific evidence, β-lapachone has a wide variety of pharmacological effects that include anti-inflammatory, anticancer, antibacterial, antifungal, antiplatelet and antiangiogenic actions.

Uses

Many of the species of Tabebuia and Handroanthus are cultivated for decorative purposes, since they are characterized by flowering before the deciduous foliage sprouts again. They are also valuable for carpentry, which appreciates the hardness, weight and resistance to water and pests of their wood; Although they are not suitable for delicate work due to the difficulty of handling them, they are optimal for outdoor material. Some species are also extremely resistant to fire.

Among the most valuable species are:

• Handroanthus chrysanthus, known as araguaney, the national tree of Venezuela, of yellow flower;
• Handroanthus chrysotrichusknown as ipê, originally from Brazil, of yellow and exceptional flower in which it blooms twice a year;
• Tabebuia donnell-smithii, called spring, native of Mexico, Central America and Cuba, where it is cultivated for ornamentation by its colorful bouquets of golden flowers;
• Handroanthus impetiginosusthe pink lapacho, native to Paraguay, Bolivia and northern Argentina, of pink flower and excellent wood;
• Handroanthus ochraceusthe yellow bark tree, yellow cortex (Costa Rica) of Central America;
• Tabebuia rosea, apamate, pink or maquilishuat u ocobo, used for urban ornamentation for having deep roots and well tolerate the esmog; pink or white flower, national tree of El Salvador;
• Handroanthus serratifoliusthe yellow lapacho, cultivated by its highly resistant wood;
• Handroanthus heptaphyllusBlack lap.

In addition to this, they receive several significant names such as Cañaguate, Cañaguatillo, Guayacán and Taelo.

• Scientific Name: Tecoma Stans. Known in Colombia likeChicalá,Fresnillo or Chirlobirlo.

The bark of many of these species, known generically as lapacho or tajy in Paraguay as tajibo in Bolivia, as primavera in Mexico and as trumpet tree in English, it is used in infusion as a fungicide and kidney treatment. The multiple claims that it has beneficial effects in the treatment of cancer have not been scientifically corroborated.

Traditional uses

Since ancient indigenous civilizations, different species of Tabebuia (especially T. impetiginosa) have been traditionally used for medicinal purposes. The inner bark of this plant is usually prepared in the form of tea and is consumed for the treatment of cancer, obesity, viral, fungal and bacterial infections; as well as inflammatory conditions: arthritis, prostatitis, colitis, skin diseases, among others.

Some populations even use this plant as a treatment for sexually transmitted diseases and as an antivenom against snake venom. Additionally, it is used as an astringent and diuretic.

Medicinal properties

Lapacho has been shown to have various therapeutic effects, among which are: anticancer properties against a variety of cancers (especially solid tumors), anti-trypanosome, antimicrobial and antimalarial activities.

As an antimicrobial, the lapachone present in Tabebuia has proven to be useful against Bacillus subtilis, Staphylococcus aureus, Helicobacter pylori, Brucella, Salmonella typhimurim and Candida albicans. For its part, 2-(hydroxymethyl)anthraquinone also has antimicrobial effects against H. pylori.

There is evidence that proves the antioxidant property of volatile compounds extracted from the bark of Tabebuia (impetiginosa) and compares this activity with that of well-known antioxidants, such as alpha-tocopherol and hydroxytoluene. butylated.

Additionally, scientific studies have shown that Tabebuia (impetiginosa) exhibits inhibitory effects on the growth of several human tumor cell lines, such as breast carcinoma (MCF-7), lung (NCI-H460), cervical carcinoma (HeLa) and hepatocellular carcinoma (HepG2).

Mechanism of action

β-lapachone exerts anticancer activity through the formation of ROS in NQO1-positive cells, inhibition of topoisomerase, modulator of the mTOR pathway. According to studies carried out, β-lapachone (isolated from T. avellanedae) significantly inhibits the proliferation of the human hepatoma cell line HepG2 by inducing apoptosis. Such apoptosis was associated with the upregulation of Bax (pro-apoptotic) and downregulation of the expression of Bcl-2 and Bcl-XL (anti-apoptotic), as well as the proteolytic activation of caspase-3 and - 9, and the degradation of the protein poly (ADP-ribose) polymerase.

Similarly, β-lapachone has also been shown to have anti-inflammatory properties by reducing neuroinflammation by modulating the expression of iNOS, proinflammatory cytokines and matrix metalloproteinases (MMP-3, MMP-8, MMP-9) in microglia stimulated with lipopolysaccharides. Thanks to the available evidence, we know that Tabebuia impetiginosa can alter the expression of signaling molecules involved in the inflammation process, including nitric oxide (NO), prostaglandin (PGE2) and leukotriene B4 (LTB4); as well as inhibiting the proinflammatory cytokines interleukin (IL)-1β and IL-6.

Taxonomy

The genre was described by Gomes former DC. and published in Bibliotheque Universelle de Geneve ser. 2. 17: 130–131. 1838. The type species is: Tabebuia uliginosa (Gomes) A. DC.

Species

• Tabebuia alba
• Tabebuia aurea
• Tabebuia caraiba
• Tabebuia chrysantha, araguaney, canehuate (Venezuela)
• Tabebuia chrysea(Venezuela)
• Tabebuia chrysotricha
• Tabebuia donnell-smithiispring, golden tree
• Tabebuia ecuador a DuckDuckGo
• Tabebuia guayacan, tree symbol of the canton of San Carlos, Costa Rica.
• Tabebuia impetiginosa, pink lapacho, ipê-rosa (Brazil)
• Tabebuia nodosa, Palo Cruz
• Tabebuia ochracea
• Tabebuia rosea, apama, apamate, orumo (Venezuela)
• Tabebuia roseo-albaipê-braco
• Tabebuia serratifolia(Venezuela), yellow poui, ipê (Brazil), yellow lapacho
• Tabebuia spectabilis, acapro (Venezuela)