Inhibitory effect of gymnemic acid on intestinal absorption of oleic acid in rats.

Gymnemic acid, a mixture of triterpene glycosides extracted from the leaves of Gymnema sylvestre, is known to inhibit the intestinal absorption of glucose in human and rats. This work examined the effect of gymnemic acid on oleic acid absorption by the method of intestinal perfusion in rats. The results showed the following. (i) Gymnemic acid potently inhibited the absorption of oleic acid in intestine. (ii) This inhibition was dose dependent and reversible. (iii) The extent of inhibition and the recovery progress were extremely similar to that of glucose absorption. (iv) Taurocholate did not affect the inhibitory effect of gymnemic acid on oleic acid absorption, but lowering its concentration facilitated the recovery from the inhibition. (v) The absorption of oleic acid was not affected by other glycosides such as phloridzin, stevioside, and glycyrrhizin. These new findings are important for understanding the roles of gymnemic acid in therapy of diabetes mellitus and obesity.