Esterification of Soybean Sterols in vitro and their Influence on Blood Cholesterol Level

Abstract

Pancreatic cholesterol esterase catalyzes the in vitro esterification of soybean sterols with fatty acids but at a slower rate than with cholesterol under comparable conditions. Bile salts are required for the esterification. Soybean sterols inhibit the increase in blood cholesterol (especially the ester fraction) of rats receiving a diet containing 2% cholesterol and 1% bile salts. The degree of inhibition was proportional to the soybean sterol concn. of the diet. It is suggested that since cholesterol esterase does not show a specificity for the different sterols that the soybean sterols compete, in the intestine, with cholesterol for the enzyme, bile salts, and fatty acids. This would impair the absorption of cholesterol by inhibiting its esterification.