Identification and characterization of sesaminol metabolites in the liver

Sesame seeds contain a number of antioxidants, such as sesamin, sesamolin, sesaminol, and sesaminol glucosides. Sesaminol triglucoside was reported to suppress oxidative stress in vivo, but little is known about the metabolism of this potentially important compound. Therefore, we have studied the metabolites of sesaminol formed in the rat liver S9 mix and excreted in the liver of rats ingesting sesaminol triglucoside for 24 h. Nuclear magnetic resonance (NMR) and mass spectrometry (MS) analyses revealed that rat liver S9 mix transformed the sesaminol into a catechol-type metabolite. On the basis of a previous study with sesame lignans by culturing the genus Aspergillus , sesaminol-6-catechol was identified as the major metabolite. Sesaminol was further converted into 5''-methylated sesaminol-6-catechol by catechol-O-methyltransferase. Moreover, we successfully detected these metabolites in the liver of rats ingesting the sesaminol triglucoside.