Chemical components of ginseng, their biotransformation products and their potential as treatment of hypertension

Ginseng is an ancient perennial herb belonging to the family Araliaceae and genus Panax which has been used for medical therapeutics for thousands of years, particularly in China and other Asian cultures although increasing interest in ginseng has recently emerged in western societies. Ginseng is a complex substance containing dozens of bioactive and potentially effective therapeutic compounds. Among the most studied are the ginsenosides, which are triterpene saponins possessing a wide array of potential therapeutic effects for many conditions. The quantity and type of ginsenoside vary greatly depending on ginseng species and their relative quantity in a given ginseng species is greatly affected by extraction processes as well as by subjecting ginseng to various procedures such as heating. Adding to the complexity of ginsenosides is their ability to undergo biotransformation to bioactive metabolites such as compound K by enteric bacteria following ingestion. Many ginsenosides exert vasodilatating effects making them potential candidates for the treatment of hypertension. Their vascular effects are likely dependent on eNOS activation resulting in the increased production of NO. One proposed end-mechanism involves the activation of calcium-activated potassium channels in vascular smooth cells resulting in reduced calcium influx and a vasodilatating effect, although other mechanisms have been proposed as discussed in this review.