Coleus forskohlii is a small perennial plant in the Lamiaceae, or mint family. Originating in India, Coleus forskohlii has been used in traditional healing modalities for centuries. The tuberous roots of Coleus forskohlii are often pickled and eaten.
The roots contain an active ingredient called forskolin. Forskolin is a type of labdane diterpenoid, compounds known for their antimicrobial and anti-inflammatory properties. Coleus forskohlii has historical applications in medicine for heart disease, respiratory disorders, abdominal colic, convulsions, and insomnia. [4, 5]
Coleus forskohlii, Forskolin & cAMP
Forskolin activates adenylate cyclase, an enzyme with important functions in nearly all cells of the human body. Adenylate cyclase creates cyclic adenosine monophosphate (cAMP) from adenosine triphosphate (ATP), leading to increased intracellular cAMP levels. [1, 5, 8]
cAMP acts as a second messenger to aid in intracellular signal transduction. cAMP is a catalyst for many hormones, including hormones of the HPA-T axis. 
cAMP stimulation by forskolin has been found to reduce inflammation, relax smooth muscle, lower blood pressure, and prevent platelet aggregation. cAMP also has important roles in modulating bronchodilation, and is a positive inotropic agent. [5, 7]
Antioxidant and Anti-inflammatory Action
Forskolin’s antioxidant and anti-inflammatory action is due to the inhibition of macrophage activation, followed by a decrease in thromboxane B2 and superoxide levels. Some studies have found forskolin to be beneficial in cases of asthma, heart disease, hypertension, and diabetes. [RR1] Forskolin’s antioxidant properties have been shown to be similar to the effects of vitamin E. 
cAMP signaling is also associated with cancer and may have antitumor effects. These include preventing cell growth and migration, increasing cancer cell sensitivity to common antitumor drugs, and stimulating mesenchymal-to-epithelial transition, which may play a role in tumor metastasis. 
Body Composition and Diabetes
Forskolin may offer benefits to body composition. Research has shown that by increasing cAMP levels, forskolin can increase lipolysis and inhibit weight gain in rats fed a high fat diet.  cAMP may also play a role in maintaining and increasing lean body mass. cAMP’s action in hormone regulation may increase basic metabolic rate, regulate the body’s thermogenic response to food, and increase the use of body fat. 
Forskolin may be effective for patients with or at risk for diabetes. Forskolin, through elevating cAMP levels, has been found to enhance insulin release by glucose. This occurs by cAMP activating two major beta cell signaling pathways. One study found chronic administration of forskolin lowered fasting glucose serum levels in healthy rats and reduced fasting hyperglycemia severity in diabetic rats. However, more research is needed to determine dosage protocol for a human population. 
cAMP is also an essential element in making melatonin. The melatonin synthesis pathway begins with tryptophan. Tryptophan is converted to 5-HTP by the enzyme tryptophan hydroxylase (TPH). Then, aromatic amino acid decarboxylase (AADC) forms serotonin from 5-HTP. Serotonin requires N-acetyltransferase (NAT) to produce N-acetylserotonin (NAS). Finally, hydroxyindole-O-methyltransferase (HIOMT) makes NAS into melatonin. [2, 6, 9]
cAMP can increase NAT transcription and activity, leading to increased melatonin synthesis. Additionally, the enzyme TPH is phosphorylated by protein kinase (PKA), which is dependent on cAMP. Heightened cAMP signaling may stimulate serotonin production through increasing TPH protein synthesis or by stabilizing TPH protein levels. Thus, more serotonin is available for the pathway to synthesize melatonin. [2, 6, 9]
1. Awasthi, P., Mahajan, V., Rather, I. A., Gupta, A. P., Rasool, S., Bedi, Y. S., … & Gandhi, S. G. (2015). Plant Omics: isolation, identification, and expression analysis of cytochrome P450 gene sequences from Coleus forskohlii. Omics: a journal of integrative biology, 19(12), 782-792.
2. Borjigin, J., & Deng, J. (2013). Diurnal 5-HT Production and Melatonin Formation.
3. Doseyici, S., Mehmetoglu, I., Toker, A., Yerlikaya, F. H., & Erbay, E. (2014). The effects of forskolin and rolipram on cAMP, cGMP and free fatty acid levels in diet induced obesity. Biotechnic & Histochemistry, 89(5), 388-392.
4. Kanne, H., Burte, N. P., Prasanna, V., & Gujjula, R. (2015). Extraction and elemental analysis of Coleus forskohlii extract. Pharmacognosy research, 7(3), 237.
5. Kavitha, C., Rajamani, K., & Vadivel, E. (2010). Coleus forskohlii A comprehensive review on morphology, phytochemistry and pharmacological aspects. Journal of Medicinal Plants Research, 4(4), 278-285.
6. Pandi-Perumal, S. R., & Cardinali, D. P. (2007). Melatonin: From molecules to therapy. Nova Publishers.
7. Ríos-Silva, M., Trujillo, X., Trujillo-Hernández, B., Sánchez-Pastor, E., Urzúa, Z., Mancilla, E., & Huerta, M. (2014). Effect of chronic administration of forskolin on glycemia and oxidative stress in rats with and without experimental diabetes. International journal of medical sciences, 11(5), 448.
8. Sapio, L., Gallo, M., Illiano, M., Chiosi, E., Naviglio, D., Spina, A., & Naviglio, S. (2016). The Natural cAMP Elevating Compound Forskolin in Cancer Therapy: Is it Time?. Journal of Cellular Physiology.
9. Watson, R. R. (Ed.). (2011). Melatonin in the Promotion of Health. CRC Press.
Disclaimer: The information provided is only intended to be general educational information to the public. It does not constitute medical advice. If you have specific questions about any medical matter or if you are suffering from any medical condition, you should consult your doctor or other professional healthcare provider.