Effect of Sesamin on the Composition of Eicosapentaenoic Acid in Liver and on Its Lymphatic Absorption in Rats

Ogawa

1998

Lipids

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In this study, we examined the effect of dietary arachidonic acid (AA) and sesame lignans on the content and n-6/n-3 ratio of polyunsaturated fatty acid (PUFA) in rat liver and the concentrations of triglyceride (TG) and ketone bodies in serum. For 4 wk, rats were fed two types of dietary oils: (i) the control oil diet groups (CO and COS): soybean oil/perilla oil = 5:1, and (ii) the AA-rich oil group (AO and AOS): AA ethyl esters/palm oil/perilla oil = 2:2:1, with (COS and AOS) or without (CO and AO) 0.5% (w/w) of sesame lignans. Dietary AA and sesame lignans significantly affected hepatic PUFA metabolism. AA content and n-6/n-3 ratio in the liver were significantly increased in the AO group, despite the dietary total of n-6 PUFA being the same in all groups, while AOS diet reduced AA content and n-6/n-3 ratio to a level similar to the CO and COS groups. These results suggest that (i) dietary AA considerably affects the hepatic profile and n-6/n-3 ratio of PUFA, and (ii) dietary sesame lignans reduce AA content and n-6/n-3 ratio in the liver. In the AO group, the concentration of acetoacetate was significantly increased, but the ratio of beta-hydroxybutyrate/acetoacetate was decreased. On the other hand, the AO diet increased the concentration of TG in serum by almost twofold as compared to other groups. However, the AOS diet significantly reduced serum TG level as compared to the AO group. In addition, the AOS diet significantly increased the acetoacetate level, but reduced the beta-hydroxybutyrate/acetoacetate ratio. These results suggest that dietary sesame lignans promote ketogenesis and reduce PUFA esterification into TG. This study resulted in two findings: (i) sesame lignans inhibited extreme changes of the n-6/n-3 ratio by reducing hepatic PUFA content, and (ii) the reduction of hepatic PUFA content may have occurred because of the effects of sesame lignans on PUFA degradation (oxidation) and esterification.

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Section: Discussionmentioning

confidence: 53%

“…Moreover, we can also consider that sesame lignans do not accelerate PUFA transportation into the peripheral tissues, because the peripheral tissue PUFA content was not increased by dietary sesame lignans (13,25). Consequently, it is probable that sesame lignans alter hepatic PUFA metabolism.…”

Section: Discussionmentioning

confidence: 99%

The metabolism and n−6/n−3 ratio of essential fatty acids in rats: Effect of dietary arachidonic acid and a mixture of sesame lignans (sesamin and episesamin)

Ogawa

1998

Lipids

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“…The next morning, after collection of lymph for 2 h (blank lymph), each animal was administered 3 mL of a test emulsion through the gastric tube, and the lymph was collected for 24 h. Lipid emulsions for intragastric administration contained 200 mg of sodium taurocholate, 50 mg bovine serum albumin (fatty acid-free, Sigma Chemical Co., St. Louis, MO), 100 mg EPA ethyl esters, 100 mg AA ethyl esters, and 50 mg of sesame lignans (sesamin and episesamin) per 3 mL of distilled water. In this experiment, EPA and AA ethyl esters were used because sesame lignans affected EPA and AA metabolism in rats in our previous studies (13)(14)(15). The mixture was emulsified by sonication just prior to use, and the lymph was collected periodically for 24 h. Experiment 3.…”

Section: Methodsmentioning

confidence: 99%

“…In addition, sesame lignans also affect lipid metabolism by inhibiting cholesterol absorption from the small intestine, reducing 3-hydroxy-3-methylglutaryl CoA reductase activity in liver microsomes (7,8), and affecting the incorporation of linoleic acid into lipid subfrac-tions (9) in rats. They also increase the content of dihomo-γlinolenic acid by inhibition of ∆5 desaturase activity in the Mortierella alpina fungus and rat liver microsomes (10)(11)(12)(13) and inhibit marked changes of the n-6/n-3 fatty acid ratio during dietary manipulation by reducing hepatic polyunsaturated fatty acid content in rat (14,15). Sesame lignans were also reported to have hypocholesterolemic effects in humans (16).…”

mentioning

confidence: 97%

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

Ogawa

1999

Lipids

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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.

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“…Therefore, the amount of daily fat intake is very important in the daily diet. Ltd., Tokyo, Japan) as described previously (28).…”

Section: Effect Of Dietarymentioning

confidence: 99%

Effect of Dietary Fat Level and Sesamin on the Polyunsaturated Fatty Acid Metabolism in Rats

Mizukuchi

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

2003

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