Dietary ginsenosides improve endothelium-dependent relaxation in the thoracic aorta of hypercholesterolemic rabbit

1. Endothelium-dependent relaxation to acetylcholine was impaired in aortic rings from cholesterol-fed rabbits as compared to rabbits fed with a control diet. 2. The dietary treatment of rabbits with ginsenosides did not affect endothelium-dependent relaxation to acetylcholine but did effect the relaxation in cholesterol-fed rabbits. 3. Dietary treatment of rabbits with ginsenosides did not alter the relaxations to sodium nitroprusside and the contractions to norepinephrine in rings without endothelium from both control and cholesterol-fed rabbits. 4. Ginsenoside feeding had no significant effect on the plasma lipid levels in both control and cholesterol-fed rabbits. 5. These results suggest that dietary supplementation of rabbits with ginsenosides improve the endothelium-dependent relaxation to acetylcholine in the aortic blood vessels in cholesterol-fed rabbits. This beneficial effect of ginsenosides feeding cannot be explained by a facilitation of the cyclic GMP effector pathway in the smooth muscle or by an enhanced cholesterol metabolism but may involve an increased production of nitric oxide by endothelial cells.