Ginsenosides of the protopanaxatriol group cause endothelium-dependent relaxation in the rat aorta.

The vasoactive effects of several ginsenosides, purified from Panax ginseng, were tested in the rat aorta. Ginsenosides from the protopanaxatriol group and its purified ginsenosides Rg1 and Re cause endothelium dependent relaxation which is associated with the formation of cyclic GMP. Both responses to these protopanaxatriol-containing ginsenosides are inhibited by methylene blue, an inhibitor of soluble guanylate cyclase and of nitric oxide synthase. In contrast, ginsenosides from the protopanaxadiol group and its purified ginsenosides Rb1 and Re do not affect vascular tone or production of cyclic GMP in the rat aorta. These findings demonstrate that ginsenosides from the protopanaxatriol group but not from the protopanaxadiol group enhance the release of nitric oxide from endothelial cells and may contribute to the beneficial effect of ginseng on the cardiovascular system.