Phorbol 12,13-dibutyrate

Phorbol 12,13-dibutyrate (PDBu) is a phorbol ester which is one of the constituents of croton oil. As an activator of protein kinase C, it is a weak tumor promoter compared to 12-"O"-tetradecanoylphorbol-13-acetate.
PDBu is widely used as a chemical reagent because of its solubility in water and other organic solvents.