Thunbergia laurifolia

Life-forms

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Eudicots
Cladus: Core eudicots
Cladus: Asterids
Cladus: Lamiids
Ordo: Lamiales

Familia: Acanthaceae
Subfamilia: Thunbergioideae
Genus: Thunbergia
Subgenus: T. subg. Hexacentris
Species: Thunbergia laurifolia
Name

Thunbergia laurifolia Lindl., 2856

Typus: Cult. in Britain, no specimen preserved. Could be lectotypified with t. 4985 in Bot. Mag.
Synonyms

Homotypic

Thunbergia grandiflora var. laurifolia (Lindl.) Benoist, Fl. Gén. Indo-Chine 4: 618. 1935.

Heterotypic

Thunbergia harrisii Hook.f., Bot. Mag. 83: t. 4998. 1857.

Distribution
Native distribution areas:

Continental: Asie
Vietnam, India (E-India), peninsular Malaysia (Kedah, Kelantan, Penang Isl., Perak, Pahan, Melaka), +Singapore, Andamans (North Andamans, Middle Andamans, South Andamans, Little Andaman Isl.), Nicobars (Car Nicobar Isl., North Nicobars, Central Nicobars, Great Nicobar Isl., Little Nicobar Isl.), Myanmar [Burma] (Bago, Kachin, Mandalay, Yangon)

References: Brummitt, R.K. 2001. TDWG – World Geographical Scheme for Recording Plant Distributions, 2nd Edition
References

Lindley, J. 1856. Gardeners' Chronicle. London 1856:260.

Links

Hassler, M. 2018. Thunbergia laurifolia. World Plants: Synonymic Checklists of the Vascular Plants of the World In: Roskovh, Y., Abucay, L., Orrell, T., Nicolson, D., Bailly, N., Kirk, P., Bourgoin, T., DeWalt, R.E., Decock, W., De Wever, A., Nieukerken, E. van, Zarucchi, J. & Penev, L., eds. 2018. Species 2000 & ITIS Catalogue of Life. Published on the internet. Accessed: 2018 Jun. 27. Reference page.
International Plant Names Index. 2018. Thunbergia laurifolia. Published online. Accessed: Jun. 27 2018.
The Plant List 2013. Thunbergia laurifolia in The Plant List Version 1.1. Published on the internet. Accessed: 2018 Jun. 27.
Tropicos.org 2018. Thunbergia laurifolia. Missouri Botanical Garden. Published on the internet. Accessed: 2018 Jun. 27.
USDA, ARS, Germplasm Resources Information Network. Thunbergia laurifolia in the Germplasm Resources Information Network (GRIN), U.S. Department of Agriculture Agricultural Research Service. Accessed: 07-Oct-06.

Vernacular names
English: laurel clock vine, blue trumpet vine
ไทย: รางจืด
中文: 桂叶山牵牛

Thunbergia laurifolia, the laurel clockvine[1] or blue trumpet vine, is native to India and Thailand[2] and the Indomalayan realm, the species occurs from Indochina to Malaysia.[3]

Description

Thunbergia laurifolia leaves are opposite, heart-shaped with serrated leaf margin and taper to a pointed tip. This species is very similar in appearance to T. grandiflora, but has longer, thinner leaves and its young stems and leaves are hairless.

The flowers are not scented and borne on pendulous inflorescences. The hermaphrodite flower is trumpet-shaped with a short broad tube, white outside and yellowish inside. The corolla is pale blue in colour with 5–7 petals, one larger than the others. Plants flower almost continuously throughout the year with flowers opening early in the morning and aborting in the evening of the same day. Carpenter bees are frequent visitors, creeping into the flowers for pollen and nectar while black ants are present probably as nectar scavengers. The plant develops a very tuberous root system.[4]

Uses
Cultivation

Thunbergia laurifolia is a popular ornamental plant in tropical gardens. It is a long-blooming vine in cultivation. Propagation is from stem cuttings or shoots from the tuberous roots. It is a fast-growing perennial herbaceous climber. It has become an exotic weed in many tropical countries.
Teas and medicinal

In Malaysia, juice from crushed leaves of T. laurifolia are taken for menorrhagia, placed into the ear for deafness, and applied for poulticing cuts and boils.[5] In Thailand, leaves are used as an antipyretic, as well as for detoxifying poisons.[6] It is locally known as akar tuau in Malaysia and rang jeud (รางจืด) in Thailand. Several Thai herbal companies have started producing and exporting rang jeud tea.[7]

T. laurifolia is used in Thailand for patients in drug addiction treatment, and two studies on lab rats show T. laurifolia may stimulate dopamine production.[8][9]
Chemistry

Iridoid glucosides have been isolated from T. laurifolia.[6] Microwave-dried leaves displayed stronger antioxidant properties than fresh leaves.[7] The antioxidant properties of the infusion from microwave-dried leaves is higher than the commercial rang jeud tea from Thailand.

Invasive species

Thunbergia laurifolia can become an invasive species where escaping from ornamental garden uses into native habitats in supportive climates. Because it is a fast-growing perennial plant it has become an escaped exotic and noxious weed in many tropical countries The plant has become a weed found in the Cerrado vegetation of Brazil and in tropical areas of Australia.
See also

Flora of India

References

"Thunbergia laurifolia". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 10 December 2015.
Starr, F. et al. (2003). "Thunbergia laurifolia". http://www.hear.org/starr/hiplants/reports/pdf/thunbergia_laurifolia.pdf
Schonenberger, J. (1999). "Floral structure, development and diversity in Thunbergia (Acanthaceae)". Botanical Journal of the Linnean Society. 130: 1–36. doi:10.1111/j.1095-8339.1999.tb00779.x.
"Thunbergia: Blue trumpet vine". Natural Resources and Mines, Queensland. 2003.
Burkill, I.H. (1966). "A Dictionary of the Economic Products of the Malay Peninsula. Volume II (I–Z)". Ministry of Agriculture and Cooperatives, Kuala Lumpur
Kanchanapoom, Tripetch; Kasai, Ryoji; Yamasaki, Kazuo (2002). "Iridoid glucosides from Thunbergia laurifolia". Phytochemistry. 60 (8): 769–71. doi:10.1016/S0031-9422(02)00139-5. PMID 12150796.
Chan, E.W.C.; Lim, Y.Y. (2006). "Antioxidant activity of Thunbergia laurifolia tea" (PDF). Journal of Tropical Forest Science. 18 (2): 130–136. Archived from the original (PDF) on 1 April 2012.
Thongsaard W, Marsden C. Effect of Thunbergia laurifolia extract on extracellular dopamine level in rat nucleus accumbens. J Med Assoc Thai. 2013 Jan;96 Suppl 1:S85-9. PMID: 23724461.
Thongsaard W, Marsden CA. A herbal medicine used in the treatment of addiction mimics the action of amphetamine on in vitro rat striatal dopamine release. Neurosci Lett. 2002 Aug 30;329(2):129-32. doi: 10.1016/s0304-3940(02)00658-4. PMID: 12165394.