Cambridge Journals Online

Research Article

Comparative analysis of sesame lignans (sesamin and sesamolin) in affecting hepatic fatty acid metabolism in rats

Jin Seon Lima1a2, Yoshikazu Adachia2, Yoko Takahashia1 and Takashi Idea1 c1 a1 Laboratory of Nutritional Function, National Food Research Institute, 2-1-12 Kannondai, Tsukuba, 305-8642, Japan a2 Graduate School of Agriculture, Ibaraki University, Ami-machi Tyuo 3-21-1, Inashiki-gun 300-0393 Ibaraki, Japan

Article author query lim js   adachi y   takahashi y   ide t

Abstract

Effects of sesamin and sesamolin (sesame lignans) on hepatic fatty acid metabolism were compared in rats. Rats were fed either a lignan-free diet, a diet containing 0·6 or 2 g/kg lignan (sesamin or sesamolin), or a diet containing both sesamin (1·4 g/kg) and sesamolin (0·6 g/kg), for 10 d. Sesamin and sesamolin dose-dependently increased the activity and mRNA abundance of various enzymes involved in hepatic fatty acid oxidation. The increase was much greater with sesamolin than with sesamin. These lignans increased parameters of hepatic fatty acid oxidation in an additive manner when added simultaneously to an experimental diet. In contrast, they decreased the activity and mRNA abundance of hepatic lipogenic enzymes despite dose-dependent effects not being necessarily obvious. Sesamin and sesamolin were equally effective in lowering parameters of lipogenesis. Sesamolin accumulated in serum at 33- and 46-fold the level of sesamin at dietary concentrations of 0·6 and 2 g/kg, respectively. The amount of sesamolin accumulated in liver was 10- and 7-fold that of sesamin at the respective dietary levels. Sesamolin rather than sesamin can account for the potent physiological effect of sesame seeds in increasing hepatic fatty acid oxidation observed previously. Differences in bio-availability may contribute to the divergent effects of sesamin and sesamolin on hepatic fatty acid oxidation. Sesamin compared to sesamolin was more effective in reducing serum and liver lipid levels despite sesamolin more strongly increasing hepatic fatty acid oxidation.

(Received April 05 2006)

(Revised September 05 2006)

(Accepted September 13 2006)

Key Words:Sesame lignan; Sesamin; Sesamolin; Fatty acid oxidation; Fatty acid synthesis

Correspondence:

^c1 *Corresponding author: Dr Takashi Ide, fax +81 29 838 7996, email idetaka@affrc.go.jp

Footnotes

Abbreviations: DGAT, diacylglycerol acyltransferase; SREBP, sterol regulatory element binding protein