The roots of Panax ginseng C.A. Meyer, better known as ginseng, have
been the most recognized herbal medicine for thousands of years in China, Korea
and Japan. The major active constituents of ginseng are ginsenosides, a diverse
group of steroidal saponins. More than 40 types of ginsenosides have been
identified; in recent years, new ginsenosides such as ginsenoside Rp1 and Rg5 are
being synthesized and characterized. Many studies have demonstrated that most of
the pharmacological and therapeutic actions of ginseng in the treatment of cancers,
diabetes and cardiovascular disorders, or in modulation of central nervous system
and endocrine functions, are attributed to ginsenosides. This review focused on
two commercially available ginsenosides - Rg3 (Rg3 Shenyi Jiaonang from China)
and it metabolites Rh2 (GOOD LIFE ginsenoside Rh2 capsule from Taiwan), and
their effects on the inhibition and prevention of cancers. Existing evidence shows
that prolonged administration of red ginseng extracts significantly reduces the
incidence of cancer. Animal studies also demonstrate that Rg3 can lower the lung
cancer risk, while Rh2 exhibits a tendency of similar benefit. Biological
investigations indicate that Rg3 and Rh2 inhibit tumor growth in vitro and in vivo
through induction of cell death, inhibition of cell proliferation, invasion and
metastasis. We also observed the anti-cancer properties of Rg3 which are related to
anti-angiogenesis. Rg3 abolished in vitro tubulogenesis of endothelial cells, in vivo
neo-vessels formation in the Matrigel plug model and ex vivo endothelial sprouting
of rat aortic fragments. Moreover, DNA microarray analysis further elucidates that
Rg3 can modulate the expression of some genes which are related to chromatin
remodeling, cytoskeleton, apoptosis, protein folding and tumor suppression. On
the other hand, multi-drug resistance is another major concern in cancer
chemotherapy. Rg3 can compete with anticancer drugs for binding to Pglycoprotein
thereby reducing the drug efflux. To this end, both of Rg3 and Rh2
exhibit promising anti-cancer and angiosuppressive abilities. However, in order to
make “ginsenoside” a safe and effective modern medicine, a deeper understanding
of its molecular mechanisms, animal studies and clinical evaluation are essential.
Keywords: Ginsenoside, saponin, ginseng, anti-angiogenesis.
