Tecoma stans (PROSEA)

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Plant Resources of South-East Asia
Introduction
List of species


Tecoma stans (L.) Juss. ex Kunth


Protologue: Humb., Bonpl. & Kunth, Nov. gen. sp. 3: 144 (1819).
Family: Bignoniaceae
Chromosome number: 2n= 36

Synonyms

Bignonia stans L. (1763), Stenolobium stans (L.) Seem. (1862).

Vernacular names

  • Yellow bells, trumpet bush (En)
  • Indonesia: tetu lang (Timor), dufa dufa (Ternate)
  • Malaysia: ai funan (Peninsular)
  • Thailand: dok lakhon (northern), thong urai, soi thong (Bangkok)
  • Vietnam: huỳnh liên.

Origin and geographic distribution

T. stans is indigenous in the southern United States and Central America, but is widely cultivated as an ornamental in the tropics and subtropics worldwide. It has naturalized in several parts of South-East Asia and the Pacific, and locally become a cumbersome weed, hampering regeneration of the indigenous vegetation.

Uses

T. stans is a well-known medicinal plant in Central America and official in e.g. the Mexican Pharmacopoeia. A decoction of the leaves is a popular diuretic, and taken to treat gastro-intestinal disorders. It is also credited with antidiabetic properties. A decoction of various plant parts is further taken as a general tonic and to treat gastritis. A decoction of the root is considered a strong diuretic and taken as a treatment for syphilis. In South-East Asia T. stans is only planted as an ornamental.

Properties

Various parts of T. stans are rich in alkaloids. Flavonoids have been found in the flowers, iridoids in the leaves. In a general screening for antimicrobial activity, a methanol extract of leaves was found to be effective against Candida albicans . In an experiment to substantiate the traditional use of T. stans in Mexican folk medicine to control diabetes mellitus, an extract showed evident hypoglycaemic action in rabbits. Intravenous administration of a T. stans infusion in dogs produced an early hyperglycaemic response and arterial hypotension followed by a slow decrease of the glucose blood values. Heart frequency was gradually increased after the first hour of drug administration and persisted for several hours. The effects observed on blood parameters seem to be related to hepatic glycogen metabolism, involving activation of glycogenolysis.

Botany

A much-branched shrub up to 4 m tall. Leaves opposite, (1-)3-7(-9)-foliolate; petiole and rachis slender; stipules absent; leaflets ovate-lanceolate, 3-10 cm × 1-4 cm, base acute, apex acuminate, irregularly serrate, slightly hirsute on midrib and in vein axils beneath, subsessile. Inflorescence an axillary or terminal, few-flowered raceme. Flowers bisexual, 5-merous, faintly scented; pedicel short, irregularly curved or twisted; calyx narrowly cylindrical-campanulate, 5-7 mm long, with subequal teeth, glabrous; corolla narrowly campanulate, 3.5-5 cm long, tube dorsiventrally compressed, lobes orbicular, subequal, bright yellow, with red stripes at the throat; stamens 4, in 2 unequal pairs, included, c. 6 mm long, sterile fifth stamen much reduced; ovary superior, narrowly cylindrical, 2-celled, lepidote, style filiform, glabrous, stigma flat. Fruit a linear, compressed capsule 10-25 cm × 0.5-0.8 cm, smooth, brown when ripe, tardily dehiscent, many-seeded. Seeds oblong, flat, c. 20 mm × 6 mm, with a membranous transparent wing on each end. Seedling with epigeal germination.

T. stans flowers and fruits profusely throughout the year in South-East Asia. The flowers are frequently visited by humming birds and sunbirds.

Tecoma comprises 13 species and occurs naturally almost exclusively from the southern United States to Argentina, but 1 species is indigenous in southern Africa, which is sometimes considered to belong to a segregate genus Tecomaria .

Ecology

In South-East Asia T. stans can be found as a garden escape and naturalized from sea-level up to 1000 m altitude.

Management T. stans is easily propagated by seed, suckers or cuttings.

Genetic resources

In view of its large natural distribution, its popularity as a garden ornamental and its preference for anthropogenic habitats, T. stans is not threatened by genetic erosion.

Prospects

Little is known about the pharmacological activities of T. stans . Further research is needed to evaluate the potential of the traditional medicinal uses, especially the use for the treatment of diabetes mellitus.

Literature

247, 576, 646, 760, 797.

Other selected sources

94, 386.

Main genus page

Authors

Mindarti Harapini