Curcumin Is Primarily Distributed in Lung, Spleen and Liver, Metabolized to Glucuronide and Sulfate, and Excreted through Bile and Urine by Using an Amorphous Curcumin Formulation with High Absorbability

Curcumin (CUR), a polyphenol, is a promising compound for use in functional foods owing to various biological properties. However, the kinetics of CUR remains unclear because CUR has extremely low water solubility and absorbability. Here, we tried to elucidate the distribution, metabolism, and excretion of CUR by using amorphous CUR, a novel formulation that has dramatically improved water solubility and absorbability. When amorphous CUR was orally administered, CUR was predominantly distributed in the lungs, spleen, and liver, with low levels of accumulation over 24 h. Moreover, most of the CUR metabolites were observed to be glucuronide and sulfate conjugates. Furthermore, CUR was found to be excreted not only in bile but also in urine. Taken together, we have systematically demonstrated the kinetics of CUR by using a highly absorbable CUR formulation. In order to develop functional foods with high quality, it is important to not only evaluate the function and toxicity of CUR but also to correctly understand its kinetics, such as absorption, distribution, accumulation, metabolism, and excretion.