Hyperlipemia-improving effects of ginsenoside-Rb2 in cholesterol-fed rats.

The effect of ginsenoside-Rb2 purified from ginseng on lipid metabolism was examined in rats fed on a high cholesterol diet. A single intraperitoneal administration of ginsenoside-Rb2 produced a significant decrease of total cholesterol, free cholesterol, low density lipoprotein (LDL)-cholesterol, triglyceride, 3-hydroxybutyrate, and acetoacetate levels in the serum. However, a significant increase of high density lipoprotein (HDL)-cholesterol level in the serum was observed after the treatment. Repeated administration of ginsenoside-Rb2 to rats with hyperlipemia induced by a high-cholesterol diet resulted in a striking decrease in the levels of total cholesterol, free cholesterol, LDL-cholesterol, and triglyceride, whereas the level of HDL-cholesterol was again increased. The changes were larger than those produced by a single intraperitoneal administration. Furthermore, the lipolytic activity of lipoprotein lipase was stimulated with a concomitant decrease in the levels of triglyceride and very low density lipoprotein (VLDL)-triglyceride in the serum. Accumulation of lipid in the adipose tissue was observed. In addition, a slight decrease in hepatic total cholesterol was observed after the treatment, but there was no statistically significant difference between the control and ginsenoside-Rb2-treated groups. The mechanism of hypolipemic action of ginsenoside-Rb2 is discussed on the basis of these results.