Coleus forskohlii

Alternative Medicine Review, March, 2006

Asthma and Allergies

Asthma and other allergic conditions are characterized by decreased cAMP levels in bronchial smooth muscle, as well as high levels of PAE In response to allergenic stimuli, mast cells degranulate, histamine is released, and bronchial smooth muscle contracts. Forskolin's activation of cAMP inhibits human basophil and mast cell degranulation, (8) resulting in subsequent bronchodilation. (14)

Research has demonstrated aerosolized dry forskolin powder results in significant relaxation of bronchial muscles and relief of asthma symptoms. In one randomized, double-blind, placebo-controlled trial, 16 asthma patients were given a single inhaled (aerosolized) 10-mg dose of dry forskolin powder, an asthma medication (0.4 mg fenoterol), or placebo. Both fenoterol and forskolin administration resulted in significant, equivalent bronchodilation, but patients taking fenoterol experienced marked finger tremor response and a decrease in plasma potassium levels. These side effects were not observed in patients receiving forskolin. (23)

In six asthmatics (ages 18-64 years), nebulized forskolin administration (1 mg and 5 mg per metered dose) resulted in an increase in forced expiratory volume. Two patients experienced immediate relief from bronchoconstriction and shortness of breath; the remaining four patients reported relief after 10-15 minutes. Blood pressure and heart rate remained stable in all patients and no tremors, palpitations, or other adverse effects were reported. (14)

Psoriasis

Like asthma, psoriasis is characterized by decreased levels of cAMP in the skin in relation to another regulating substance, cyclic guanosine monophosphate (cGMP). This imbalance results in a much higher rate of cell division--1,000 times greater than normal, resulting in psoriatic outbreaks. Although study details are not available, Ammon et al reported an improvement in symptoms of psoriasis in four patients supplemented with forskolin. The ability of forskolin to regulate cAMP levels in skin cells has been shown to have therapeutic benefit for sufferers of psoriasis. (4)

Glaucoma

Glaucoma is characterized by elevated intraocular pressure (IOP). Several animal and human studies have demonstrated the ability of forskolin to lower IOP, possibly via cAMP activation and a reduction in aqueous flow. (10, 24-26)

Caprioli et al demonstrated a significant decrease in IOP in rabbits, monkeys, and humans administered a topical forskolin suspension (1% forskolin). This effect was present at one hour post application and remained significant for at least five hours. (26) In one clinical trial of 20 young, healthy Japanese volunteers, two 50 [micro]L topical instillations of one-percent forskolin were applied to one eye while the other eye served as control, receiving only the topical vehicle. At one-hour post instillation, the IOP fell 2.4 [ or -] 1.3 mmHg and aqueous flow rate was reduced by 13 percent in the treatment eye compared to the control. Both results were statistically significant. (25)