Comparative Study of Sesame Lignans (Sesamin, Episesamin and Sesamolin) Affecting Gene Expression Profile and Fatty Acid Oxidation in Rat Liver

Abstract

SummaryThe impact of sesamin, episesamin and sesamolin (sesame lignans) on hepatic gene expression profiles was compared with a DNA microarray. Male Sprague-Dawley rats were fed experimental diets containing 0.2% sesamin, episesamin or sesamolin, and a control diet free of lignans for 15 d. Compared to a lignan-free diet, a diet containing sesamin, episesamin and sesamolin caused 1.5-and 2-fold changes in the expression of 128 and 40, 526 and 152, and 516 and 140 genes, respectively. The lignans modified not only the mRNA levels of many enzymes involved in hepatic fatty acid oxidation, but also those of proteins involved in the transportation of fatty acids into hepatocytes and their organelles, and regulating hepatic concentrations of carnitine, CoA and malonyl-CoA. It is apparent that sesame lignans stimulate hepatic fatty acid oxidation by affecting the gene expression of various proteins regulating hepatic fatty acid metabolism. We also observed that lignans modified the gene expression of various proteins involved in hepatic lipogenesis, cholesterogenesis and glucose metabolism. The changes were generally greater with episesamin and sesamolin than with sesamin. In terms of the amounts accumulated in serum and the liver, the lignans ranked in the order sesamolin, episesamin and sesamin. The differences in bioavailability among these lignans appear to be important to their divergent physiological activities.

Comparison of Metabolism of Sesamin and Episesamin by Drug-Metabolizing Enzymes in Human Liver

“…The biological effects of sesamin and episesamin were compared previously (Kushiro et al, 2002;Ide et al, 2009). Kushiro et al (2002) demonstrated that episesamin was much stronger at increasing the activity and gene expression of the enzymes involved in fatty acid oxidation in the liver of rats fed 0.2% of sesamin or episesamin for 15 days.…”

Comparative Effects of Sesame Seeds Differing in Lignan Contents and Composition on Fatty Acid Oxidation in Rat Liver

“…Compared to sesamin, sesamolin and episesamin had a much stronger effect on fatty acid oxidation and miscellaneous genes involved in fatty acid transport and metabolism, except for those involved in lipogenesis 15 . However, the present observation showed that seeds from ME variety, which contained fat-soluble lignan predominantly as sesamin and was almost devoid of sesamolin, was as effective as seeds from GZ and MH varieties, which contained sesamin and sesamolin at about a 2:1 ratio, in affecting the parameter of hepatic fatty acid oxidation.…”

“…It has been indicated that Cd36 38 and carnitine transporter genes 39 are under the control of PPARα. We previously observed that fat-soluble lignans increased the mRNA expression of Cd36, a transporter involved in fatty acid uptake, and carnitine transporter 15 . Therefore, it is conceivable that these changes represent the consequence of PPARα activation by the lignans contained in sesame seeds.…”

“…And the levels in these groups were significantly lower than the values observed in the animals fed seeds rich in lignans from GZ, MH and ME varieties. We previously observed that sesame lignans increased mRNA levels of transporters involved in hepatic uptake of fatty acid Cd36/fatty acid translocase and carnitine carnitine transporter 15 . We therefore measured mRNA levels of these proteins and the concentration of carnitine in the liver among rats fed seeds from various sesame varieties.…”

“…We used sesame seed powder from a conventional variety that is popular in Japan Masekin MK and seeds rich in fat-soluble lignans sesamin and sesamolin from Gomazou GZ 19 , Maruhime MH 20 and Maruemon ME 20 . The sesamin and sesamolin contents of sesame seeds were determined as described previously 15 , and were 4.1 and 2.4 g/kg for MK, 8.7 and 3.4 g/kg for GZ, 8.7 and 4.1 g/kg for MH and 12.6 and 0.4 g/kg for ME, respectively. Therefore, the sum of the values of sesamin and sesamolin was about two times higher in GZ, MH and ME than in MK.…”