The metabolism and distribution of sesame lignans (sesamin and episesamin) in rats.

In this study, we examined the distribution and metabolism of refined sesame oil lignans (sesamin and episesamin) in rat. For 8 wk rats were fed the diet including 0.5% (w/w) sesame lignans (sesamin and episesamin) with 5% (w/w) corn oil or eicosapentaenoic acid (EPA)-rich oil. The concentrations of sesamin and episesamin in rat liver after their administration for 8 wk were very low; both of them were less than 0.5 microgram/g liver. These were observed in both oil groups although the fatty acid compositions of dietary oils were completely different. No significant difference existed in lymphatic absorption between sesamin and episesamin. To investigate the distribution of sesamin and episesamin in rats, the concentrations of sesamin and episesamin were determined in tissues and serum within 24 h after administration to rats. Sesamin and episesamin may be, at first, incorporated into the liver and then transported to the other tissues (lung, heart, kidney, and brain). They are lost from the body within 24 h after administration. There was no significant difference in lymphatic absorption between sesamin and episesamin, but the amount of sesamin was significantly lower than that of episesamin in all tissues and serum. These results suggest that sesamin is absorbed in lymph the same as episesamin, but that sesamin is subsequently metabolized faster by the liver.