Phorbol

Phorbol is a natural, plant-derived organic compound. It is a member of the tigliane family of diterpenes. It was first isolated in 1934 as the hydrolysis product of croton oil, which is derived from the seeds of Croton tiglium. Phorbol's structure was determined in 1967. It is very soluble in most polar organic solvents, as well as in water.

Various esters of phorbol have important biological properties, the most notable of which is the capacity to act as tumor promoters through activation of protein kinase C. They mimic diacylglycerols, glycerol derivatives in which two hydroxyl groups have reacted with fatty acids to form esters. The most common phorbol ester is 12-O-tetradecanoylphorbol-13-acetate (TPA), also called phorbol-12-myristate-13-acetate (PMA), which is used as biomedical research tool in models of carcinogenesis. PMA, together with ionomycin, can also be used to stimulate T-cell cytokine production, and is used in protocols for intracellular staining of these cytokines.