The metabolism and excretion of curcumin (1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) in the rat.

Curcumin labelled with deuterium and tritium was prepared. Oral and intraperitoneal doses of [3H]curcumin led to the faecal excretion of most of the radioactivity. 2. Intravenous and intraperitoneal doses of [3H]curcumin were well excreted in the bile of cannulated rats. 3. The major biliary metabolites were glucuronides of tetrahydrocurcumin and hexahydrocurcumin. A minor biliary metabolite was dihydroferulic acid together with traces of ferulic acid. Metabolites were identified using chemical ionization mass spectrometry.