Forskolin, Coleus forskohlii. Adenylate Cyclase Activator. Forskolin, is a cell permeable diterpenoid isolated from Coleus forskohlii. Forskolin has a unique ability to stimulate adenylate cyclase activity and increase cyclic adenosine monophosphate (cAMP). Cell Signaling Activators and Inhibitors; Adenylate Cyclase Activator.