Curcumin (CCM)

Curcumin is a diarylheptanoid. Curcumin can exist in several tautomeric forms, including a 1,3-diketo form and two equivalent enol forms. The enol form is more energetically stable in the solid phase and in solution. Curcumin can be used for boron quantification in the curcumin method. It reacts with boric acid to form a red-colored compound, rosocyanine. Curcumin is brightly yellow colored and may be used as a food coloring. As a food additive, its E number is E100. Curcumin incorporates several functional groups. The aromatic ring systems, which are phenols, are connected by two α,β-unsaturated carbonyl groups. The diketones form stable enols and are readily deprotonated to form enolates; the α,β-unsaturated carbonyl group is a good Michael acceptor and undergoes nucleophilic addition. The structure was first identified in 1910 by J. Miłobędzka, Stanisław Kostanecki and Wiktor Lampe.