(Andrews) Benth. ex G.Don
Coleus barbatus, also known by the synonyms Plectranthus barbatus and incorrectly Coleus forskalaei (and other spellings of this epithet), is a tropical perennial plant related to the typical coleus species. It produces forskolin, an extract useful for pharmaceutical preparations and research in cell biology.
The Brazilian name is boldo brasileiro (Portuguese pronunciation: [ˈbowdu bɾɐziˈlejɾu], or boldo gaúcho, as opposed to the Chilean true boldo), boldo-da-terra ([ˈbowdu dɐ ˈtɛʁɐ]), boldo-de-jardim ([ˈbowdu dʒi ʒaʁˈdʒĩ]) or tapete-de-Oxalá ([tɐˈpetʃi dʒ oʃaˈla]) (Oxalá's carpet, because of its velvety texture).
Coleus barbatus was first described by Henry Cranke Andrews in 1810 as Plectranthus barbatus. It was transferred to Coleus by Bentham in 1830. Although Coleus was previously sunk into Plectranthus, the original binomial was revived in a major study of the subtribe Plectranthinae in 2019.
There has been some confusion over the synonyms of this species. Plectranthus forskaolaei was first described by Vahl in 1790. Vahl's name is illegitimate, because he treats it as a synonym of the earlier described Ocimum hadiense Forrsk. Vahl spelt the epithet as "Forskålaei", referring to Pehr Forsskål, whose surname is also spelt "Forskål". The International Code of Nomenclature for algae, fungi, and plants at Art. 60.7 specifies that "å" is to be replaced by "ao".
Willdenow in 1800 referred to Vahl's name, but spelt the epithet "forskolaei". (As of 31 July 2020[update], the International Plant Names Index had the spelling "forskalei".) It was probably this species that Briquet referred to when transferring a species to Coleus as "C. forskohlii (Willd.) Briq.", introducing yet another spelling of the epithet; however, Briquet did not explicitly refer to a basionym. Briquet regarded "Coleus forskohlii" as synonymous with what he called "C. barbatus Benth.", although Vahl had originally given a different synonymy. Paton et al. (2019) state that the epithets "forskalaei" or "forskohlii" are incorrectly applied to this species, instead treating binomials with these epithets as synonyms of Coleus hadiensis, in accordance with Vahl's original use.
Herbal teas made from Coleus barbatus contain rosmarinic acid and also flavonoid glucuronides and diterpenoids. The chemical constituents of Plectranthus barbatus showed activities in vitro, such as acetylcholinesterase inhibition.
- 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.
- Alasbahi, R. H.; Melzig, M. F. (2010). "Plectranthus barbatus: A review of phytochemistry, ethnobotanical uses and pharmacology - Part 1". Planta Medica. 76 (7): 653–61. doi:10.1055/s-0029-1240898. PMID 20178070.
- "Plectranthus barbatus Andrews". The International Plant Names Index. Retrieved 2020-07-31.
- "Coleus barbatus (Andrews) Benth. ex G.Don". The International Plant Names Index. Retrieved 2020-07-31.
- "Coleus barbatus Andrews", Plants of the World Online, Royal Botanic Gardens, Kew, retrieved 2020-07-31
- Vahl, M. (1790), "Plectranthus Forskålaei", Symbolae Botanicae, p. 44, OCLC 475396338, retrieved 2020-07-31
- "Forsskål, Pehr (1732-1763)". The International Plant Names Index. Retrieved 2020-07-31.
- Turland, N.J.; et al., eds. (2018). "Art. 60". International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code) adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017 (electronic ed.). Glashütten: International Association for Plant Taxonomy. Retrieved 2020-07-31.
- Willdenow, C.L. von (1800), "4. Plectranthus Forskolaei", Species Plantarum, 3 (4th ed.), p. 169, retrieved 2020-07-31
- "Plectranthus forskalaei Willd". The International Plant Names Index. Retrieved 2020-07-31.
- Briquet, J.I. (1897), "144. Coleus Lour.", Naturlichen Pflanzenfamilien, section IV, subsection 3a, p. 359, retrieved 2020-07-31
- Falé, P.L., Borges, C., Madeira, P.J.A., Ascensão, L.; et al. (2009). "Rosmarinic acid, scutellarein 4′-methyl ether 7-O-glucuronide and (16S)-coleon E are the main compounds responsible for the antiacetylcholinesterase and antioxidant activity in herbal tea of Plectranthus barbatus ("falso boldo")". Food Chem. 114 (3): 798–805. doi:10.1016/j.foodchem.2008.10.015.CS1 maint: multiple names: authors list (link)
- Porfírio S, Falé PL, Madeira PJ, Florêncio MH, Ascensão L, Serralheiro ML (2010). "Antiacetylcholinesterase and antioxidant activities of Plectranthus barbatus tea, after in vitro gastrointestinal metabolism". Food Chem. 122: 179–187. doi:10.1016/j.foodchem.2010.02.044.
- Pizzorno, Joseph E.; Murray, Michael T. (2012). Textbook of Natural Medicine (4th ed.). Edinburgh: Churchill Livingstone. p. 686. ISBN 9781437723335.
- Dubey MP, Srimal RC, Nityanand S, et al. (1981). "Pharmacological studies on coleonol, a hypotensive diterpene from Coleus forskohlii". J Ethnopharmacol. 3 (1): 1–13. doi:10.1016/0378-8741(81)90010-6. PMID 7193263.