Role of Panax ginseng and ginsenosides in regulating cholesterol homeostasis

Hypercholesterolemia is harmful for human health since it may favor atherosclerosis and increase the risk of cardiovascular disease. To investigate the effect of a Panax ginseng extract and of some major components thereof (namely, ginsenosides Rb1 and Rb2) on cholesterol homeostasis in vitro, we quantitated total and free cholesterol levels and monitored the changes in the levels of key mediators of cholesterol synthesis, efflux and clearance. Treatments with ginsenosides and the extract reduced intracellular cholesterol levels by modulating the SREBP-2-HMGCR and LXR-IDOL signaling pathways. In addition, we observed an upregulation of the expression of the membrane transporters ABCA1 and ABCG1 and of cholesterol 7-hydroxylase suggesting the stimulation of processes for cholesterol excretion and cholesterol conversion into bile acids. Furthermore, both ginsenosides targeted HMGCR and inhibited its activity via a statin-like mechanism. Globally, our findings aid in deciphering the mechanisms of action of a major class of ginseng components in regulating lipid metabolism.