Bioavailability and metabolism of curcuminoids

Abstract

Curcuminoids are biologically active polyphenols present in the spice and coloring agent turmeric. Dietary intake of curcuminoids has been associated a wide range of medicinal properties, including possible bene fi cial effects in the prevention of many forms of cancer. Studies carried out in vitro on cultured cells show that curcuminoids reduce the rate of cell division and induce apoptosis by affecting signal transduction pathways. However, there is a discrepancy between the curcuminoid dosage required for these in vitro effects and the most optimistic estimates on curcuminoid bioavailability following oral uptake. Therefore, the mechanism by which curcuminoids exert their biological effects through dietary intake remains incompletely understood. Curcuminoid bioavailability is dependent on several factors. These include solubility, chemical stability, efficiency of digestive uptake, metabolic processing, and excretion. This review attempts to illuminate the current state of knowledge on the effect of these factors on curcuminoid bioavailability. In addition, efforts to augment curcuminoid bioavailability through chemical modifications, improved solubilization, increased stability, or alternative routes of administration are addressed.