Coleus

Coleus (Coleus forskohlii) is a traditional Ayurvedic herb which belongs to the mint family. One of the constituents in coleus is called forskolin. Forskolin is an adenylyl cyclase stimulator which increases cellular levels of a molecule called cyclic adenosine monophosphate (cAMP). cAMP is a vital, cell regulating compound involved in a variety of cellular functions. Coleus has anti-inflammatory and digestive effects, and has been claimed to improve psoriasis by elevating cAMP levels. Further research is needed to confirm these effects since forskolin is most often used as a research tool in vitro, or outside the body, such as in a test tube or petri dish. Forskolin may act differently inside the body. 

Forskolin has been shown to increase the production of thyroid hormones and stimulate their release so it may have similar effects on the thyroid gland as thyroid stimulating hormone, leading to its reputation as a thyroid stimulant. In Ayurveda coleus is known as a herb that increases thyroid hormone production and secretion. It can help normalise thyroid hormone levels if a person has subclinical autoimmune thyroid disease. It may also be of benefit in the maintenance of a healthy metabolism, and positively affect fat and protein metabolism, making it useful for weight management assistance in obesity and type 2 diabetes. The insulin resistance and metabolic syndrome picture associated with non-alcoholic fatty liver disease can be treated with coleus.

Coleus and forskolin lower blood pressure and improve the contractility of the heart muscle making this herb relevant in the treatment of hypertension, congestive heart failure and angina. These actions are related to an increase in cAMP levels throughout the cardiovascular system which results in relaxation of the arteries and increased force of contraction. The net effect is an improvement in many cardiovascular functions. It may also be useful as a bronchodilator in asthma, emphysema and chronic bronchitis because increased cAMP levels result in relaxation of bronchial muscles.