Curcumin, bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione, is a yellow-orange pigment which can be synthesised chemically or isolated from the plant Curcuma longa L. Curcumin has a rather broad absorption peak in the range 300-500 nm (maximum approximately 430 nm) and has potential as a photosensitiser for treatment of localised superficial infections in e.g., the mouth or skin.

Natural curcumin was evaluated as a potential photosensitizer for oral applications. The photocytotoxicity of curcumin on salivary gland acinar cells (SM 10-12) was investigated in five aqueous preparations consisting of 5% DMSO, non-ionic micelles, cyclodextrin, liposomes, or a hydrophilic polymer.