Sulfate conjugates are the major metabolites in rats administrated with sesamin

Sesamin is known to have various biological effects. Although several metabolites of sesamin have been identified, its metabolism by phase II enzymes remains unclear, because usually its sulfo- and glucurono-conjugates in plasma and urine are analyzed after sulfatase/β-glucuronidase treatment. In this study, the metabolites of sesamin in rats administrated with sesamin (100 mg/kg b.w.) were analyzed without sulfatase/β-glucuronidase treatment. Two sulfate conjugates of sesamin monocatechol (SC-1) were detected in the liver and plasma. Their Cmax values were 5- and 10-times higher than that of sesamin itself. The Vmax/Km values for sulfate conjugation in the cytosol fraction of human liver were 1.7-times larger than that in the cytosol fraction of rat liver, suggesting that sulfate conjugation also occurs in human liver. The recombinant human proteins SULT1A1, 1A3, 1B1, and 1E1 expressed in Saccharomyces cerevisiae cells produced sulfate conjugates effectively. Our results could help revealing the mechanism of physiological effects of sesamin. [Display omitted] The major metabolites of sesamin in rats taken sesamin were sulfate conjugates.