Anticancer and Antineurodegenerative Effects of Ginsenosides

Ginseng is a medicinal plant widely used for the treatment of various human conditions. The pharmacological effects of ginseng have been demonstrated in cancer, diabetes, and cardiovascular diseases and ginseng has been used for promoting immune functions, improving central nervous system (CNS), and relieving stress. In this review, we take an overview of two hot topics, ie, anticancer and antineurodegenerative effects of ginsenosides and their possible mechanisms in detail. Ginsenosides are unique triterpenoidal saponins found exclusively in Panax species and have a common four-ring hydrophobic steroid-like structure with a different number of sugar moieties. According to the number and position of these sugar moieties, ginsenosides are classified into two major groups: 20[S]-protopanaxadiol and 20[S]-protopanaxatriol saponins. The diversity of sugar components between ginsenosides might be specific in action for each ginsenoside. Ginseng and ginsenosides have been used for cancer prevention and further cancer treatment as an adjuvant supplement. People who consume ginseng preparation are frequently at low risk of cancer in stomach, liver, pancreas, ovaries, colon, and oral cavity. Although a complex mixture of compounds in these plants, the ginsenosides are mostly responsible for the pharmacological effects of these ginsengs, and Rg3 and Rh2 are recognized as major active saponins. The anticarcinogenic effects of ginseng are described, based on the diverse mechanisms, including cell cytotoxicity and differentiation, antitumor related to inflammation, antimetastasis and inhibition of angiogenesis, synergistic effect on chemical therapeutic agents, and decreasing multidrug resistance. Recently, there is increasing evidence on beneficial effects of ginsenosides to the CNS. Especially a wealth of literature has been presented reporting on ginsenosides' effects on neurodegenerative diseases such as Parkinsons' disease and Alzheimer's disease. Using a wide range of in vitro and in vivo models, researchers have explored the pharmacological actions of ginsenosides on synaptic activity, oxidative stress, membrane stabilization, and antiapoptosis in CNS against various disease conditions. Modulatory roles of ginsenosides on these activities have been reported to extend stimulatory effects on the brain functions or to protect the CNS against neurodegenerative diseases.