How is sesamin metabolised in the human liver to show its biological effects?

Sesamin is a major lignan found in sesame and is known to have various biological effects. Some of these biological effects occur following its metabolic conversion to corresponding catechols and, therefore, the study of sesamin metabolism is quite important. There is currently a need to identify the enzymes responsible for metabolism of sesamin so that scientists will be more able to predict sesamin-drug interactions. The authors reviewed all the published literature with a focus on papers that dealt with metabolism of sesamin by drug-metabolising enzymes in rat and/or human liver, such as cytochrome P450 and UDP-glucuronosyltransferase. The article also reviews papers that dealt with the inhibition of enzymes by sesamin including drug-metabolising enzymes and other physiologically important enzymes. Additionally, the authors discuss the species-based differences in the metabolism of sesamin between rats and humans. A remarkable species-based difference was found in sesamin metabolism between humans and other animals; thus, it is very important that precautions are taken when predicting the physiological effects in humans from animal data. A mechanism-based inhibition of human CYP2C9 by sesamin was recently discovered, suggesting that it is important to evaluate the interaction between sesamin and drugs that are mainly metabolised by CYP2C9. Furthermore, further analysis of sesamin and episesamin and their molecular mechanisms are needed to make better use of sesamin supplements.