Title:Stereoscopic Differences in the Identification, Bioactivity, and Metabolism
of C-20 and C-24 Epimeric Ginseng Saponins
Volume: 23
Issue: 7
Author(s): Juan Zhang, Ruolin Zhao, Guige Hou*, Qibao Wang, Fenglan Zhao, Zhi Liu*Qingguo Meng*
Affiliation:
- School of Pharmacy, Binzhou Medical University, Yantai
264003, China
- Suzhou Medinoah Co., Ltd., Suzhou, 215000, P.R. China
- School of Pharmacy, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Yantai University, Yantai, 264005, P.R. China
Keywords:
Saponin, epimer, identification, bioactivity, metabolism, stereoscopic difference.
Abstract: Ginseng, the roots and/or rhizomes of Panax spp.(Araliaceae), has been used as a
popular herbal medicine in East Asia for at least two millennia. As a functional food and healthenhancing
supplement, ginseng has been shown to have a wide range of pharmacological effects
on cognition and blood circulation as well as antioxidant, antitumor, and anti-fatigue effects. The
main active properties of ginseng are considered to be the triterpene saponins, often referred to as
ginsenosides, which are the basis for their wide-ranging pharmacological effects. Four of these
glycosides, including protopanaxadiol, protopanaxatriol, ocotillol, and oleanolic acid, are the most
common saponins found in ginseng. Compared to other ginsenosides, the C-20 chimeric ginsenosides,
including Rg3, Rh2, Rg2, Rh1, PF11, C-20, and C-24, as well as epimeric ocotillol-type
saponins and their derivatives exhibit significant, steric differences in biological activity and metabolism.
20(R)-ginseng saponins, one class of important rare ginsenosides, have antitumor, antioxidative,
antifatigue, neuroprotective and osteoclastogenesis inhibitory effects. However, 20(R)-
ginsenosides are rare in natural products and are usually prepared from 20(S)-isomers through
chemical differential isomerization and microbial transformation. The C20 configuration of
20(R)-ginseng saponins is usually determined by 13C NMR and X-ray single-crystal diffraction.
There are regular differences in the chemical shift values of some of the carbons of the 20(S)- and
20(R)-epimers, including C-17, C-21, and C-22. Owing to their chemical structure and pharmacological
and stereoselective properties, 20(R)-ginseng saponins have attracted a great deal of attention
in recent years. Herein, the stereoscopic differences in the identification, bioactivity, and metabolism
of C-20 and C-24 epimeric ginseng saponins are summarized.
