© H. Zell · CC BY-SA 3.0 · Commons
Coleus barbatus
Caution🐾Harfensträucher · (Plectranthus barbatus)
Mint family (Lamiaceae)
Description
Known in Brazil and East Africa as 'falso boldo', the leaves of this coleus relative (Lamiaceae) are traditionally brewed as a tea for digestive complaints, flatulence and liver troubles. The plant's real claim to fame, however, lies in its root: it contains forskolin, which directly activates adenylyl cyclase and raises intracellular cAMP levels — a mechanism well characterised in vitro and in animal studies, and the basis for extracts explored for circulatory support. Rosmarinic acid and related compounds have also been shown in cell-culture studies to inhibit the enzyme acetylcholinesterase. Externally, crushed leaves were applied to wounds in African folk medicine. Because forskolin lowers blood pressure and inhibits platelet function, caution is warranted alongside blood-pressure or anticoagulant medication; the plant is contraindicated in pregnancy due to its potential effect on uterine muscle, and no data exist for children under 12.
CONTRAINDICATED during pregnancy
Forskolin stimulates cAMP in smooth uterine muscle and may alter uterine tone. Contraindicated during pregnancy; no safety data available.
In Brazilian and African folk medicine, the leaves of Indian coleus ('falso boldo') are used as a tea for digestive complaints, liver ailments, and flatulence. Coleon E and rosmarinic acid contribute to the antispasmodic and digestive properties. This use is well documented ethnobotanically; no EMA monograph exists.
Preparation & dosage
Pour 200 ml boiling water over 2–4 g dried leaves, steep 10 minutes, strain. Up to 3 cups daily, not longer than 4 weeks without medical advice.
- Dry amount
- 2–4 g
- Doses per day
- 3×
Forskolin-rich root extracts of Plectranthus barbatus directly activate adenylyl cyclase and elevate intracellular cAMP levels, producing positive inotropy and vasodilation. This mechanism has been characterised in vitro and in animal studies. Clinical human trials with standardised extracts for heart failure are limited; the underlying pharmacology is established.
Preparation & dosage
Prefer standardised ready-made preparations (forskolin content 10–20 mg/dose). Use only under medical supervision for cardiovascular indications.
In East Africa and the Arabian Peninsula, leaf infusions are traditionally used for colds, bronchitis, and coughs. Forskolin derivatives can relieve bronchospasm; cAMP elevation relaxes smooth bronchial muscle. The antitussive effect is well attested ethnobotanically; clinical data are sparse.
Preparation & dosage
Steep 2–3 g leaves in 200 ml boiling water for 10 minutes, strain. Twice daily for respiratory complaints.
- Dry amount
- 2–3 g
- Doses per day
- 2×
Rosmarinic acid and scutellarein 4'-methyl ether 7-O-glucuronide from Plectranthus barbatus inhibit acetylcholinesterase (AChE) in vitro. This inhibition may support cholinergic neurotransmission, relevant for memory and cognitive function. Efficacy has been demonstrated in cell culture and enzyme assay studies.
Preparation & dosage
Ethanolic leaf extract (1:5, 40% ethanol): 2–3 ml twice daily. Supplement only — do not self-treat cognitive disorders.
In African folk medicine, fresh leaves are crushed and applied as a poultice to wounds, ulcers, and skin infections. Abietane diterpenoids from the leaves show antimicrobial activity against gram-negative and gram-positive bacteria.
The essential oil from leaves and calyx glands contains camphor, cineole, and other monoterpenes. It is used in folk medicine externally for skin irritations, insect stings, and as an antiseptic. Antimicrobial activity of the terpene components is confirmed in vitro.
Root extracts of Plectranthus barbatus are used in Ayurvedic and Brazilian folk medicine for immune support and as a general tonic. Forskolin modulates cAMP-dependent immune signalling pathways. Robust clinical data for immunomodulatory effects in humans are lacking.
Forskolin-containing extracts may lower blood pressure and interact with antihypertensives or anticoagulants. Do not self-medicate cardiovascular conditions. Use with caution in gastric or duodenal ulcer. Not for children under 12 years. No long-term use (>4 weeks) without medical advice. ASPCA classification (accessed 2026-08-10): toxic to dogs, cats and horses.
⏱ Max continuous use: 4 weeks
Forskolin stimulates cAMP in smooth uterine muscle and may alter uterine tone. Contraindicated during pregnancy; no safety data available.
No data on transfer of forskolin or other constituents into breast milk. Avoid as a precaution.
No clinical data for children. Traditional use limited to adults. Not under 12 years without medical advice.
Drug interactions
Antihypertensiva (Blutdrucksenker)
Forskolin lowers peripheral vascular resistance via cAMP activation; additive blood pressure-lowering effect possible.
Antikoagulantien / Thrombozytenaggregationshemmer
cAMP elevation by forskolin inhibits platelet aggregation; combined bleeding tendency with concurrent anticoagulation.
Theophyllin / PDE-Hemmer
Synergistic cAMP rise through inhibition of cAMP degradation (theophylline) and activation of adenylyl cyclase (forskolin).
Contraindications
- Pregnancy (uterine-stimulating potential of forskolin)
- Existing bleeding tendency or use of anticoagulant medications
- Gastric or duodenal ulcer (forskolin-induced gastric acid secretion possible)
Harvested part: leaves
- Time of day:
- Morning after dew has dried, before the peak midday heat
- Drying:
- Spread leaves at 35–40 °C in a shaded, well-ventilated room. Do not bundle — mould risk. Dry when they rustle.
- Storage:
- 12 months — Store in dark, tightly sealed glass jars or paper bags at cool, dry room temperature.
- Time of day:
- No time-of-day restriction; harvest roots after the first die-back of shoots (maximum forskolin content after growth period).
- Drying:
- Dry root pieces (1–3 cm) at 40–50 °C until brittle. Forskolin content degrades at higher temperatures.
- Storage:
- 24 months — Store dark, dry, cool (<20 °C) in glass jars. Check forskolin content regularly if possible.
- Forskolin (Coleonol)OtherContent: 0.1-0.6 %Root
Labdane diterpenoid; characteristic compound of Plectranthus barbatus; direct activator of adenylyl cyclase, raises cAMP in virtually all mammalian cells. Key pharmacologically active principle.
- Rosmarinsäure / Rosmarinic acidPhenolic acidContent: 0.5-2 %Leaf
Dominant phenolic acid in P. barbatus leaves; inhibits acetylcholinesterase and butyrylcholinesterase; strongly antioxidant and anti-inflammatory.
- Coleon E / (16S)-Coleon EOtherLeaf
Abietane diterpenoid from P. barbatus; inhibits AChE and shows antioxidant activity; together with rosmarinic acid the main active component of the herbal tea.
- Scutellarein-4'-methylether-7-O-GlucuronidFlavonoidLeaf
Flavone glycoside in P. barbatus tea; together with rosmarinic acid one of the acetylcholinesterase-inhibiting lead compounds in the infusion.
- Abietanditerpenoide (Plectracoloide A/B u. a.)OtherRoot
Group of abietane diterpenoids newly described in 2022 (Ishii et al.); show in vitro antimicrobial and antiparasitic activity.
- LuteolinFlavonoidLeaf
Flavone in Lamiaceae leaves; anti-inflammatory through inhibition of NF-κB and COX-2; antioxidant complement to rosmarinic acid.
- Camphor / Cineol (ätherisches Öl)Essential oilContent: 0.1-1.5 %Leaf
Main components of the essential oil in leaves and calyx glands; antimicrobial, mildly analgesic externally; give the plant its characteristic odour.
- Ursolsäure / Ursolic acidOtherAerial parts
Triterpenic acid in P. barbatus; anti-inflammatory and hepatoprotective; supports the liver use in folk medicine.
- [1]MonographAlasbahi & Melzig (2010): Plectranthus barbatus: A Review of Phytochemistry, Ethnobotanical Uses and Pharmacology – Part 1. Planta Medica 76(7):653-661. DOI 10.1055/s-0029-1240898(accessed: 2026-05-24)
- [2]MonographAlasbahi & Melzig (2010): Plectranthus barbatus: A Review of Phytochemistry, Ethnobotanical Uses and Pharmacology – Part 2. Planta Medica 76(8):753-765. DOI 10.1055/s-0029-1240919(accessed: 2026-05-24)
- [3]MonographChen et al. (2009): In Vitro Skin Diffusion Study of Pure Forskolin versus a Forskolin-Containing Plectranthus barbatus Root Extract. J. Nat. Prod. 72(4):769-771. DOI 10.1021/np800541k(accessed: 2026-05-24)
- [4]MonographFalé 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. Food Chemistry 114(3):798-805. DOI 10.1016/j.foodchem.2008.10.015(accessed: 2026-05-24)
- [5]MonographFalé et al. (2008): Acetylcholinesterase inhibition by Rosmarinic acid from Plectranthus (Lamiaceae) species. Planta Medica 74(09):1284. DOI 10.1055/s-0028-1084086(accessed: 2026-05-24)
- [6]MonographMothana et al. (2014): In Vitro Antiprotozoal Activity of Abietane Diterpenoids Isolated from Plectranthus barbatus Andr. Int. J. Mol. Sci. 15(5):8360-8371. DOI 10.3390/ijms15058360(accessed: 2026-05-24)
- [7]MonographIshii et al. (2022): Two New Abietane Diterpenoids from Plectranthus barbatus. Chemistry of Natural Compounds 58(5):860-863. DOI 10.1007/s10600-022-03712-y(accessed: 2026-05-24)
- [8]MonographYan et al. (1998): Conversion of Forskolin-Insensitive to Forskolin-Sensitive (Mouse-Type IX) Adenylyl Cyclase. Molecular Pharmacology 53(2):182-187. DOI 10.1124/mol.53.2.182(accessed: 2026-05-24)
- [9]MonographASPCA Animal Poison Control — Coleus (Coleus ampoinicus): Toxic to Dogs, Toxic to Cats, Toxic to Horses(accessed: 2026-08-10)
Distribution in Europe
🪴 Grow at home
- ☀ Light
- bright, indirect
- 💧 Water
- weekly
- 🌱 Soil
- Standard potting compost
- 🪴 Pot
- 20 cm
- ⭐ Difficulty
- ★☆☆ beginner
- 🐾 Pets
- toxic to pets
Tips:
- Very robust — forgives care mistakes.
- Cuttings root easily in a glass of water.
Care tips are general indoor-gardening recommendations, not scientific sources.