Thunbergia laurifolia Lindl.

Last updated: 20 Jun 2016

Scientific Name

Thunbergia laurifolia Lindl.

Synonyms

Thunbergia grandiflora var. laurifolia (Lindl.) Benoist [1]

Vernacular Name

Malaysia Daun patok tuau, akar tuau, akar ketuau, rumput melian, lana [2], akar tuwauh, daun patok ketuwah, daun patok tuwah, tuwauh [3]
English Purple allamanda [3]
Thailand Nam na, ya kio [2]
Germany Malayische thunbergie [4].

Geographical Distributions

Thunbergia laurflora was brought into European cultivation from Peninsular Malaysia. [2]

Botanical Description

T. laurflora is a member of the Acanthaceae family. It is a climbing shrub with much branching. The young branches being terete and green and glabrous. [5]

The leaves are opposite with long petiole, oblong-lanceolate, acuminate, entire or sometimes a little toothed. There are three nerves which are reticulated with transverse nerves. The petiolea measure 5-7 cm long, slender, remarkable for being incrassated both at the apex and at the base. At the apex the thickened portion is nearly terete while at the base the incrassation extends for a greater length, and is flattened or plane on the upper side, and even slightly winged. [5]

The raceme of flowers, both axillary and terminal, sometimes bearing a few flower, and destitute of leaves; at other times the raceme consists of whorled flowers, with a pari of opposite leaves at the base, which are smaller than those of the stem. The bracteas of vaginant leaves or large scales, resembling a spatha, open and free at the lower edge, adherent by the upper margin, faintly striated; this embrases the lower gibbous portion of the tube of corolla.  The calyx is very small, cup-shaped, dotted. The corolla very large, pale blue, with a yellowish eye. The tube is obliquely funnel-shaped, wide at the mouth. The limb is very large, spreading, five-lobedl; lobes rotundate, deeply emarginatem, almost bifid. The stamens are quite included, inserted near the base of the tube of the corolla. The filaments are broad, subulate, curved. The anthers are oblong, apiculate, fringed in front, and having two subulate spurs at the base. The ovary is sublong, but included within the tube of the corolla; stigma bifidl; each lobe channelled within. [5]

Cultivation

No documentation

Chemical Constituent

No documentation

Plant Part Used

Leaves and flowers [4][6]

Traditional Use

In Malaysia, the decoction of the leaves are used in the treatment of menorrhagia. [4] Poultice of the leaves makes good remedy for boils, cuts and ulcers as practised by traditional healers of the Malay Peninsula. [4] Juice extracted from the flowers are used in treatment of eye diseases. [4]

Preclinical Data

Pharmacology

Antidrug addiction activity

T. laurifolia or known as Rang Chuet in Thailand had been used to treat drug addiction successfully by Thai traditional medicine men. The mechanism of action of various extracts of the leaves of was studied. In 2002, it was found that the crude water extract was able to increase K(+)-stimulated dopamine release from rat striatal slices comparable to Amphetamine. In a follow up to this study they published another paper in 2005, the effects of methanol extract of the leaves on cerebral activities of rats were reported. It was found that the extract increased signal intensity in the following areas of the brain: nucleus accumbens, globus pallidus, amygdala, frontal cortex, caudate putemen and the hippocampus. This indicates that the extract increases significantly neuronal activity in specific brain regions responsible for reward and locomotor behaviour. [6][7]

Liver detoxification and protective activity

An in vitro and in vivo study of the potential hepatoprotective activity of T. laurifolia found that the addition of aqueous extracts of the leaves of T. laurifolia caused an increase in MTT back to normal levels and reduce the ALT and AST levels following exposure of rat hepatocytes to ethanol. In the in vivo study the aqueous extract of the leaves of T. laurifolia were able to normalize the effects of ethanol on rat liver evidenced by the normalization of Htg, ALT and AST. [7]

Antidiabetic acitivity

The aqueous extract of the leaves of T. laurifolia was able to reduce the increased of blood sugar level in alloxan-induced diabetic rats. The recovery of some beta-cells of the pancreas was observed eventhough not completely normal. This is indicative of its antidiabetic potentials however, the exact mechanism has still got to be worked out. [8]

Toxicity

Chronic toxicity studies on the leave extract of T. laurifolia found that it did not induce and adverse nor toxic effects in the groups of Wistar rats. [9]

Clinical Data

Clinical findings

No documentation

Adverse reaction

The sap of T. laurifolia is irritant to the skin and can cause dermatitis especially on sensitive skin. [4]

Interaction & Depletion

No documentation

Dosage

No documentation

Poisonous Management

No documentation

Line drawing

No documentation

References

  1. The Plant List. Ver1.1. Thunbergia laurifolia Lindl.[homepage on the Internet]. c2013 [updated 2012 Apr 18; cited 2016 Jun 17] Available from: http://www.theplantlist.org/tpl1.1/record/tro-102966
  2. Herbal Medicine Research Centre, Institute for Medical Research. Compendium of medicinal plants used in Malaysia. Volume 2. Kuala Lumpur: HMRC IMR, 2002; p. 390.
  3. Quattrocchi U. CRC world dictionary of medicinal and poisonous plants: Common names, scientific names, eponyms, synonyms, and etymology. Volume V R-Z. Boca Raton, Florida: CRC Press, 2012; p. 569.
  4. Ong HC. Tanaman hiasan: Khasiat makanan & ubatan. Kuala Lumpur: Utusan Publications & Distributors Sdn Bhd, 2006; p. 60.
  5. Hooker WJ. Curtis's botanical magazine. Volume 83, No. 4998. London: Lovell Reeve, Henbietta Street, Covent Garden; 1857.
  6. Thongsaard W, Marsden CA, Morris P, Prior M, Shah YB. Effect of Thunbergia laurifolia, a Thai natural product used to treat drug addiction, on cerebral activity detected by functional magnetic resonance imaging in the rat. Psychopharmacology (Berl). 2005;180(4):752-760.
  7. Pramyothin P, Chirdchupunsare H, Rungsipipat A. Hepatoprotective activity of Thunbergia laurifolia Linn extract in rats treated with ethanol: In vitro and in vivo studies. J Ethnopharmacol. 2005;102(3):408-411.
  8. Aritajat S, Wutteerapol S, Saenphet K. Anti-diabetic effect of Thunbergia laurifolia Linn. aqueous extract. Southeast Asian J Trop Med Public Health. 2004;35 Suppl 2:53-58.
  9. Chivapat S, Chavalittumrong P, Attawish A. Chronic toxicity of Thunbergia laurifolia Lindl. extract. J Thai Tradit Altern Med. 2009;7(1):17-24.