Ginseng is any of eleven different varieties of short, slow growing perennial plants with fleshy roots. Ginseng is believed to restore and enhance normal well-being and has become one of the most popular herbal remedies in the world today.
The following main ginseng health benefits have been suggested:
Ginseng may help with stimulating physical and mental activity among people who are weak and tired. The mental and energy boosts from ginseng are smooth and not like that from coffee. Ginseng has been shown to reduce fatigue and increase energy in cancer patients. It’s one of the more useful herbal remedies for chronic fatigue syndrome (CFS).
Ginseng may improve thinking ability and cognition. Ginseng works as a brain booster and protector. It can improve mental performance and ability to concentrate. It also prevents memory loss, protects against age-related mental decline and improves memory in stroke patients.
There may be substances in ginseng that have anticancer properties and protective against some kinds of cancer including lung, liver, pancreatic, ovarian, and stomach cancers.
Ginseng species contains ginsenosides, polysaccharides, amino acids, peptides, polyacetylenic alcohols and fatty acids. Growing evidence has demonstrated that these components possess physiological effects in biological systems, in which ginsenosides are the principal pharmacologically active component. More than thirty ginsenosides have been identified and are broadly classified into three categories: the 20(S)-protopanaxadiol (PPD) (Rb1, Rb2, Rb3, Rc, Rd, Rg3, Rh2, Rs1), the 20(S)-protopanaxatriol (PPT) (Re, Rf, Rg1, Rg2, Rh1), and the oleanolic acid group (Ro). Moreover, several rare ginsenosides, such as the ocotillol saponin F11 (24-R-pseudoginsenoside) and the pentacyclic oleanane saponin Ro (3,28-O-bisdesmoside) have also been identified.
Also, ginsenosides can be categorized into either pro-oxidative or anti-oxidative according to structural configuration. Ginsenosides with no sugar moieties attached to the C-20 position of the triterpene dammarane act as pro-oxidants (e.g. Rg3, Rh2, and Rg2), while a mere glucose attached to the C-6 position, but not C-20, rendered the ginsenoside an antioxidant (e.g. Rh1).
The adopted nomenclature of ginsenosides is based on the distribution where “R” stands for the root and the chromatographic polarity from the least polar to the most polar one alphabetically (i.e., “a” is less polar than “b” and so forth). The content and composition of ginsenosides in ginseng can vary depending on the species, age, cultivation methods, part of the plant, preservation method, season of harvest, and extraction method. For examples, ginsenoside-Rg2 and -Rf can only be found in the Asian ginseng and are absent from American ginseng. Recently, ginsenoside-Ra1, -Ra2, -Ra3, -Rg4, -Rg5, -Rg6, -Rk1, -Rs1 and -Rs2 have further been identified in the red ginseng. In Asia, red ginseng is more expensive than white ginseng due to the presence of the additional ginsenosides and supposed better medical efficacy.
Ginsenosides are triterpene saponins. Most ginsenosides are composed of a dammarane skeleton (17 carbons in a four-ring structure) with various sugar moieties (e.g. glucose, rhamnose, xylose and arabinose) attached to the C-3 and C-20 positions. The extra hydroxyl group or sugar derivatives at the C-6 position of the PPT defines the major structural difference from the PPD. Conformationally, all ginsenosides have a flat core A-B-C-D fused ring. Thus, sugar substitutes on ginsenosides neither collide with each other nor cause significant steric crowding. The side-chain structures of ginsenosides are relatively flexible and are highly dependent on the solvent and local environments.
Leung K W. Ginseng pharmacology: Signaling pathways of ginsenoside-Rg1 in human umbilical vein endothelial cells[M]. HONG KONG BAPTIST UNIVERSITY (HONG KONG), 2006.