Coleus amboinicus, synonym Plectranthus amboinicus,[1] is a semi-succulent perennial plant in the family Lamiaceae[2] with a pungent oregano-like flavor and odor. Coleus amboinicus is considered to be native to parts of Africa, the Arabian Peninsula, and India,[3] although it is widely cultivated and naturalized elsewhere in the tropics where it is used as a spice and ornamental plant.[2] Common names in English include Indian borage, country borage, French thyme, Indian mint, Mexican mint, Cuban oregano, soup mint, Spanish thyme.[2] The species epithet, amboinicus refers to Ambon Island, in Indonesia, where it was apparently encountered and described by João de Loureiro (1717–1791).[4][full citation needed]

Coleus amboinicus
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Lamiales
Family: Lamiaceae
Genus: Coleus
C. amboinicus
Binomial name
Coleus amboinicus
  • Plectranthus amboinicus Lour.
  • Coleus aromaticus Benth.

Description edit

A member of the mint family Lamiaceae,[2] Coleus amboinicus grows up to 1 m (3.3 ft) tall. The stem is fleshy, about 30–90 cm (12–35 in), either with long rigid hairs (hispidly villous) or densely covered with soft, short and erect hairs (tomentose). Old stems are smooth (glabrescent).

Leaves are 5–7 cm (2.0–2.8 in) by 4–6 cm (1.6–2.4 in), fleshy, undivided (simple), broad, egg/oval-shaped with a tapering tip (ovate). The margins are coarsely crenate to dentate-crenate except in the base. They are thickly studded with hairs (pubescent), with the lower surface possessing the most numerous glandular hairs, giving a frosted appearance. The petiole is 2–4.5 cm (0.79–1.77 in). The aroma of the leaves can be described as a pungent combination of the aromas of oregano, thyme, and turpentine.[5] The taste of the leaves is described as being similar to the one of oregano, but with a sharp mint-like flavor.[6]

Flowers are on a short stem (shortly pedicelled), pale purplish, in dense 10-20 (or more) flowered dense whorls (cymes), at distant intervals, in a long slender spike-like raceme. Rachis 10–20 cm (3.9–7.9 in), fleshy and pubescent. The bracts are broadly ovate, 3–4 cm (1.2–1.6 in) long, acute. The calyx is campanulate, 2–4 mm (0.079–0.157 in) long, hirsute and glandular, subequally 5-toothed, upper tooth broadly ovate-oblong, obtuse, abruptly acute, lateral and lower teeth acute. Corolla blue, curved and declinate, 8–12 mm (0.31–0.47 in) long, tube 3–4 mm (0.12–0.16 in) long. Trumpet-like widened; limb 2-lipped, upper lip short, erect, puberulent, lower lip long, concave. Filaments are fused below into a tube around the style.

The seeds (nutlets) are smooth, pale-brown, roundish flattened, c. 0.7 by 0.5 mm (0.028 by 0.020 in).[7]

Distribution and habitat edit

Coleus amboinicus is native to Southern and Eastern Africa, from South Africa (KwaZulu-Natal) and Eswatini to Angola and Mozambique and north to Kenya and Tanzania, where it grows in woodland or coastal bush, on rocky slopes and loamy or sandy flats at low elevations.[8][9][10] From Southern Africa it would have been carried by Arabs and other traders to Arabia, India and Southeast Asia along the Indian Ocean maritime trade routes. The plant also currently grows in mainland India. The plant was later brought to Europe, and then from Spain to the Americas, hence the name Spanish thyme.[8][11]

Research edit

In basic research, the effects of the essential oil were tested with other plant essential oils for possible use as a mosquito repellant.[2][12]

Uses edit

The leaves are strongly flavoured.[10] The herb is used as a substitute for oregano to mask the strong odors and flavors of fish, mutton, and goat.[11] Fresh leaves are used to scent laundry and hair.[2] It is also grown as an ornamental plant.[2][13] In the southern Indian state of Karnataka, it is batter fried to make pakodas.[14] The leaves can be used to make rasam[15] and a herbal remedy[16] (kashayam) that offers symptomatic relief from cold and sniffles.

Variegated Cuban oregano (Coleus amboinicus 'Variegatus')

Phytochemicals edit

The main chemical compounds found in the essential oil of Coleus amboinicus are carvacrol (28.65%), thymol (21.66%), α-humulene (9.67%), undecanal (8.29%), γ-terpinene (7.76%), p-cymene (6.46%), caryophyllene oxide (5.85%), α-terpineol (3.28%), and β-selinene (2.01%).[17] Another analysis obtained thymol (41.3%), carvacrol (13.25%), 1,8-cineole (5.45%), eugenol (4.40%), caryophyllene (4.20%), terpinolene (3.75%), α-pinene (3.20%), β-pinene (2.50%), methyl eugenol (2.10%), and β-phellandrene (1.90%). The variations can be attributed to the methodology used in the extraction process, seasonal variations, soil type, climate, genetic and geographical variations of the plant.[18]

Cultivation edit

Coleus amboinicus is a fast-growing plant commonly grown in gardens and indoors in pots. Propagation is by stem cuttings, but it can also be grown from seeds. In dry climates the herb grows easily in a well-drained, semi-shaded position. It is frost tender (USDA hardiness zones 10–11)[19] and grows well in subtropical and tropical locations, but will do well in cooler climates if grown in a pot and brought indoors, or moved to a warm, sheltered position in winter. In Hawaii and other humid tropical locations, the plant requires full sun.[5] It can be harvested throughout the growing season to be used fresh, dried, or frozen.[20]

Common names edit

Gallery edit

See also edit

References edit

  1. ^ a b Paton, Alan J.; Mwanyambo, Montfort; Govaerts, Rafaël H.A.; Smitha, Kokkaraniyil; Suddee, Somran; Phillipson, Peter B.; Wilson, Trevor C.; Forster, Paul I. & Culham, Alastair (2019). "Nomenclatural changes in Coleus and Plectranthus (Lamiaceae): a tale of more than two genera". PhytoKeys (129): 1–158. doi:10.3897/phytokeys.129.34988. PMC 6717120. PMID 31523157.
  2. ^ a b c d e f g "Plectranthus amboinicus (Indian borage), Datasheet, Invasive Species Compendium". Centre for Agriculture and Biosciences International. 23 November 2017. Retrieved 13 March 2020.
  3. ^ "Coleus amboinicus Lour.". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 2021-08-30.
  4. ^, accessed 23 May 2020
  5. ^ a b Culinary herbs, by Ernest Small, National Research Council of Canada NRC Research Press, 1997, p. 488.
  6. ^ Florida's Best Herbs and Spices: Native and Exotic Plants Grown for Scent and Flavor, by Charles R. Boning, Pineapple Press Inc, 2010 p. 75.
  7. ^ Flora Malesiana, Vol. 8, by Steenis, C. G. G. J. van (Cornelis Gijsbert Gerrit Jan); Steenis-Kruseman, M. J. van; Indonesia. Department Pertanian; Lembaga Ilmu Pengetahuan Indonesia; Kebun Raya Indonesia, Publication date 1950, p. 387. Available on
  8. ^ a b Codd, L. E. W. et al. Flora of Southern Africa : the Republic of South Africa, Basutoland, Swaziland and South West Africa. Vol. 28, part 4, 1981, page 148. Available on Biodiversity Heritage Library at
  9. ^ Flora Malesiana, Vol. 8, by Steenis, C. G. G. J. van (Cornelis Gijsbert Gerrit Jan); Steenis-Kruseman, M. J. van; Indonesia. Departemen Pertanian; Lembaga Ilmu Pengetahuan Indonesia; Kebun Raya Indonesia, Publication date 1950, p. 387. Available on
  10. ^ a b c d e f g "Plectranthus amboinicus". Germplasm Resources Information Network. Agricultural Research Service, United States Department of Agriculture. Retrieved 21 August 2012.
  11. ^ a b George Staples; Michael S. Kristiansen (1999). Ethnic Culinary Herbs: A Guide to Identification and Cultivation in Hawaii. University of Hawaii Press. p. 88. ISBN 978-0-8248-2094-7.
  12. ^ Lalthazuali; Mathew, N (2017). "Mosquito repellent activity of volatile oils from selected aromatic plants". Parasitology Research. 116 (2): 821–825. doi:10.1007/s00436-016-5351-4. PMID 28013374. S2CID 5158038.
  13. ^ The Herbalist in the Kitchen, by Gary Allen, University of Illinois Press, 2010, p. 198.
  14. ^ "Doddapatre Bajji (Coleus aromaticus Pakora)". Savi-Ruchi. Retrieved 2023-04-24.
  15. ^ "Karpooravalli rasam". Priya's Virundhu. Retrieved 2023-08-01.
  16. ^ "Karpooravalli Kashayam for Cold". Priya's Virundhu. Retrieved 2023-08-01.
  17. ^ Senthilkumar, A; Venkatesalu, V (2010). "Chemical composition and larvicidal activity of the essential oil of Plectranthus amboinicus (Lour.) Spreng against Anopheles stephensi: A malarial vector mosquito". Parasitology Research. 107 (5): 1275–8. doi:10.1007/s00436-010-1996-6. PMID 20668876. S2CID 6776822.
  18. ^ Lopes, P. Q; Carneiro, F. B; De Sousa, A. L; Santos, S. G; Oliveira, E. E; Soares, L. A (2017). "Technological Evaluation of Emulsions Containing the Volatile Oil from Leaves of Plectranthus Amboinicus Lour". Pharmacognosy Magazine. 13 (49): 159–167. doi:10.4103/0973-1296.197646 (inactive 1 August 2023). PMC 5307902. PMID 28216901.{{cite journal}}: CS1 maint: DOI inactive as of August 2023 (link)
  19. ^ "Plectranthus amboinicus". Fine Gardening. Retrieved 2017-07-18.
  20. ^ "Cuban Oregano (Plectranthus amboinicus) | My Garden Life". Retrieved 2022-02-08.
  21. ^ Gary Allen, The Herbalist in the Kitchen, University of Illinois Press, 2010, p. 198.
  22. ^ a b c Tropicos,, accessed 21 August 2012
  23. ^ a b Encyclopedia of Life,, accessed 21 August 2012
  24. ^ [1] and [2] (both in Spanish)