INFLUENCE OF SESAME LIGNANS ON VARIOUS LIPID PARAMETERS IN RATS

A lignan mixture from sesame salad oil containing episesamin and sesamin as major components was fed to rats. Lignans at the dietary level of approximately 0.2% tended to decrease plasma and liver cholesterol levels with an accompanying increase in the fecal excretion of neutral steroids, particularly when the dietary fat source was evening primrose oil containing γ-linolenic acid. There was a decreasing trend in the specific activity of Δ5-desaturase in liver microsomes whereas that of Δ6-desaturase tended to increase, in particular in rats fed with safflower oil. The proportion of dihomo-γ-linolenate increased in response to the reduction of Δ5-desaturation activity, and that of docosapentaenoate (n-6) decreased in liver phosphatidylcholine in both groups of rats, suggesting that lignans interfered with various steps of linoleate metabolism. However, the production by the aorta of prostacyclin and by platelets of thromboxane A2 was not influenced by lignans. Thus, episesamin and/or sesamin functioned as a regulator of cholesterol and linoleate metabolism in rats. © 1990 by the Japan Society for Bioscience, Biotechnology, and Agrochemistry.