Effects of Synthetic Glycosides on Cholesterol Absorption a

The glycosides contained in an extract of alfalfa meal, operationally named alfalfa saponins,' prevent the hypercholesterolemia expected in monkeys given highcholesterol diets," as well as preventing the development of atherosclerosis in cholesterol-fed rabbits.' They also induce regression of atherosclerosis in cholesterolfed monkeys4 Although the mechanism of these effects has not been totally unraveled, it is likely that it involves lowered intestinal absorption of c h o l e s t e r 0 1 ~ ~ ~ ~ ~ and increased fecal excretion of neutral steroids and bile acids.3 Because of the complex nature of the alfalfa extract, which contains more than thirty different saponins, peptides, carbohydrates, and pigments, and probably other unidentified material,' I deemed it important to study glycosides with chemically defined structures. Consequently, a small series of glycosides was synthesized. This series contained the aglycone tigogenin, present in digitonin saponins," which prevents hypercholesterolemia in monkeys: or diosgenin, a spirostane derivative closely related to tigogenin. Subsequently, I studied the effects of these glycosides on intestinal absorption of cholesterol in rats.