Articles

Coleus

Plant Part Used

Root

Active Constituents

The major constituent with pharmacological activity is forskolin.(1),(13)

[span class=alert]This section is a list of chemical entities identified in this dietary supplement to possess pharmacological activity. This list does not imply that other, yet unidentified, constituents do not influence the pharmacological activity of this dietary supplement nor does it imply that any one constituent possesses greater influence on the overall pharmacological effect of this dietary supplement.[/span]

Introduction

Coleus (Coleus forskohlii) is in the mint family (Lamiaceae) and is a traditional medicine in Hindu and Ayurvedic medicine. Coleus has been researched over the last few decades, with most studies focused on the isolated constituent forskolin. Current research supports that the whole plant is actually more effective. Many compounds in coleus may act synergistically to improve biological function in the body. There have been numerous studies to support its hypotensive (blood pressure lowering) and spasmolytic effects.(2),(3)

Interactions and Depletions

Interactions

Dosage Info

Dosage Range

250mg (1% standardized extract), 1-3 times a day
-OR-
50mg (18% standardized extract), 1-2 times a day.

Most Common Dosage

250mg (1% standardized extract), 2 times a day
-OR-
50mg (18% standardized extract), 2 times a day.

Standardization

[span class=doc]Standardization represents the complete body of information and controls that serve to enhance the batch to batch consistency of a botanical product, including but not limited to the presence of a marker compound at a defined level or within a defined range.[/span]

The most current available medical and scientific literature indicates that this dietary supplement should be standardized to 1% forskolin. This dietary supplement can also be standardized to 18% forskolin.

Uses

Frequently Reported Uses

  • Cardiovascular conditions, including angina, hypertension and CHF
  • Allergies/asthma
  • Glaucoma
  • Skin conditions including psoriasis and eczema
Other Reported Uses
  • Weight loss support
  • Anti-inflammatory
  • Antiviral

Toxicities & Precautions

General

There is little known risk of toxicity with coleus.

Health Conditions

Based on human data, coleus may aggravate hypotension (low blood pressure), peptic ulcer disease or any bleeding disorder.(4) It should be used with caution in individuals with these conditions.

Coleus may increase stomach acidity; use with caution in those with peptic ulcer or GERD.(15)

Use with caution in thyroid disorders, as Coleus has been reported in laboratory studies to stimulate thyroid hormone release.(16)

Pregnancy/ Breast Feeding

Coleus is not recommended in pregnancy or breastfeeding. Laboratory animal studies have reported that Coleus may delay fetal development, affect implantation of the embryo in the uterus, and may increase the risk of miscarriage.(17)

Age Limitations

Do not use in children under 2 years of age unless recommended by a physician.

Pharmacology

Coleus is reported to have two significant mechanisms of action. First, it is claimed to activate the enzyme, adenylate cyclase.(5) This action would have the effect of increasing cyclic adenosine monophosphate (c-AMP) within the cells. C-AMP is important in the activation of several biochemical pathways. C-AMP is formed when a specific neurotransmitter binds to the cell membrane and stimulates the formation of adenylate cyclase. Specific hormonal messengers bind to receptor sites to create the release of c-AMP. This is called transmembrane activation. Coleus reportedly creates c-AMP activation independent of receptor site specificity.(6) Coleus may also stimulate other enzymatic activity independent of c-AMP activation, but this is not known at this time. The stimulation of c-AMP has an impact on body chemistry in several ways. It stimulates thyroid function, increases insulin secretion, inhibits mast cell release of histamine, and increases the burning of fats as fuels.(7)

Coleus is claimed to inhibit platelet activating factor (PAF) by possibly directly binding to PAF receptor sites.(8),(9) PAF is a key factor in allergic and inflammatory pathways. By inhibiting it, neutrophil activation may be inhibited, vascular permeability reduced, smooth muscle contraction decreased, and coronary blood flow increased.(10) It should be noted that the antiplatelet activity of forskolin has been reported to be potentiated by the concurrent administration of dipyridamole.(9)

Oral ingestion of forskolin (250 mg of 10% forskolin extract twice a day) for a 12-week period was reported in a clinical trial to favorably alter body composition while concurrently increasing bone mass and serum free testosterone levels in overweight and obese men, indicating that forskolin is a possible therapeutic agent for the management and treatment of obesity.(18)

In asthma, Coleus is reported to help improve cAMP levels in bronchial smooth muscle, as well as inhibit basophil and mast cell degranulation.(19)

Coleus may be beneficial in psoriasis and other skin disorders by increasing c-AMP in epidermal cells, increasing the rate of cell maturation and turnover.(11) Also of interest, is the topical use of forskolin in glaucoma (0.5mg), which was reported to lower intraocular pressure in laboratory animals and humans by stimulating adenylate cyclase.(12)

Animal studies support the use of coleus for glaucoma. Several animal and human studies have demonstrated the ability of forskolin to lower intraocular pressure (IOP), possibly via cAMP activation and a reduction in aqueous flow.(20),(21) A randomized, double-blind, placebo-controlled, cross-over trial found the use of forskolin 1% ophthalmic suspension in 10 healthy, non-smoking men resulted in decreases in IOP, but the differences between the forskolin treatment and placebo treatment at eight hours post application were statistically insignificant.(22)

Laboratory studies have reported that forskolin stimulates thyroid hormone release and increases thyroid hormone production.(14),(16) Forskolin has been reported to stimulate digestive secretions, including hydrochloric acid, pepsin, amylase, and pancreatic enzymes.(15) Laboratory animal studies have also found that forskolin has antidepressant activity probably through activation of cAMP.(23)

Coleus has also been reported in laboratory studies to have antiviral activity against HIV NL4-3.(24)

References

  1. Ammon HP, et al. Forskolin: From an Ayurvedic Remedy to a Modern Agent. Planta Medica. 1985;51: 473-77.
  2. View Abstract: Bhat SV, et al. The Antihypertensive and Positive Inotropic Diterpene Forskolin: Effects of Structural Modifications on Its Activity. J Med Chem. 1983;26:486-92.
  3. View Abstract: Baumann G, et al. Cardiovascular Effects of Forskolin (HL 362) in Patients with Idiopathic Congestive Cardiomyopathy -- A Comparative Study with Dobutamine and Sodium Nitroprusside. Cardiovasc Pharmacol. 1990;16(1):93-100.
  4. View Abstract: Lindner E, et al. Positive Inotropic and Blood Pressure Lowering Activity of a Diterpene Derivative Isolated from Coleus forskohli: Forskolin. Arzneim-Forsch/Drug Res. 1978;28:284-89.
  5. Seamon KB, et al. Forskolin: Its Biological and Chemical Properties. In: Advances in Cyclic Nucleotide and Protein Phosphorylation Research. vol. 20. New York: Raven Press;1986:1-150.
  6. View Abstract: Doi K, et al. The Effect of Adenylate Cyclase Stimulation on Endocochlear Potential in the Guinea Pig. Eur Arch Otorhinolaryngol. 1990;247(1):16-19.
  7. View Abstract: Kreutner RW. Bronchodilator and Antiallergy Activity of Forskolin. European Journal of Pharmacology. 1985;111:1-8.
  8. View Abstract: Christenson JT, et al. The Effect of Forskolin on Blood Flow, Platelet Metabolism, Aggregation and ATP Release. Vasa. 1995;24(1):56-61.
  9. View Abstract: Agarwal KC, et al. Significance of Plasma Adenosine in the Antiplatelet Activity of Forskolin: Potentiation by Dipyridamole and Dilazep. Thromb Haemost. 1989;61(1):106-10.
  10. View Abstract: Marone G, et al. Inhibition of IgE-mediated Release of Histamine and Peptide Leukotriene from Human Basophils and Mast Cells by Forskolin. Biochem Pharmacol. 1987;36(1):13-20.
  11. View Abstract: De Vries GW, et al. Effect of Forskolin on Beta-adrenergic Hyporesponsiveness in Skin. Skin Pharmacol. 1998;1(2):106-14.
  12. View Abstract: Caprioli J, et al. Adenylate Cyclase Stimulation and Intraocular Pressure Reduction by Forskolin Analogs. J Ocul Pharmacol. 1989;5(3):181-87.
  13. Zhang W, Kong L. [Chemical constituents in the introduced Coleus forskohlii] Zhongguo Zhong Yao Za Zhi. Aug 2009;34(16):2060-2062. Chinese.
  14. Haye B, Aublin JL, Champion S, et al. Chronic and acute effects of forskolin on isolated thyroid cell metabolism. Mol Cell Endocrinol. 1985;43:41-50.
  15. Seamon KB, Padgett W, Daly JW. Forskolin: unique diterpene activator of adenylate cyclase in membranes and intact cells. Proc Natl Acad Sci U S A .1981;78:3363-3367.
  16. Féliers D, Dang PM, Haye B, Pavlovic-Hournac M. Forskolin mimics TSH action on the expression of protein kinase C isozymes in pig thyroid cell cultures. Cell Signal. Jul 1994;6(5):513-522.
  17. Almeida FC, Lemonica IP. The toxic effects of Coleus barbatus B. on the different periods of pregnancy in rats. J Ethnopharmacol. Nov 2000;73(1-2):53-60.
  18. Godard MP, Johnson BA, Richmond SR. Body composition and hormonal adaptations associated with forskolin consumption in overweight and obese men. Obes Res. 2005;13(8):1335-1343.
  19. Lichey I, Friedrich T, Priesnitz M, et al. Effect of forskolin on methacholine-induced bronchoconstriction in extrinsic asthmatics. Lancet.1984:2:167.
  20. Caprioli J, Sears M. Forskolin lowers intraocular pressure in rabbits, monkeys, and man. Lancet. 1983;1:958-960.
  21. Caprioli J, Sears M, Bausher L, et al. Forskolin lowers intraocular pressure by reducing aqueous inflow. Invest Ophthalmol Vis Sci.1984;25:268-277.
  22. Meyer BH, Stulting AA, Muller FO, et al. The effects of forskolin eye drops on intra-ocular pressure. S Afr Med J. 1987;71:570-571.
  23. Wachtel H, Loschmann PA. Effects of forskolin and cyclic nucleotides in animal models predictive of antidepressant activity: interactions with rolipram. Psychopharmacology. (Berl) 1986;90:430-435.
  24. Bodiwala HS, Sabde S, Mitra D, Bhutani KK, Singh IP. Anti-HIV diterpenes from Coleus forskohlii. Nat Prod Commun. Sep 2009;4(9):1173-1175.