Panax ginseng: properties, uses, and research

Panax Ginseng (Korean ginseng) has been a staple in the Eastern medical apothecary for centuries. The introduction of Eastern medicine to the Western world has raised awareness of the potential of Panax ginseng for healing. In particular, Panax ginseng has been indicated for enhancing nervous system functioning, neuroendocrine functioning, carbohydrate and lipid metabolism, cardiovascular functioning, immune functioning, and other functions related the effects of nitric oxide (NO), which is synthesized from L-argine and catalyzed by a family of enzymes known as nitric oxide synthases (NOS).

Research has shown that specialized cells may induce NOS formation including murine macrophages, endothelial, smooth muscle cells, and cardiac myocytes. Induced NOS, known as iNOS, is associated with a series of conditions including inflammatory and infectious illnesses. iNOS is therefore a type of immune response, as NO appears to suppress T-cell proliferation. NO also helps defend against bacterial infection via the inflammatory response.

The major active components of Panax ginseng are ginsenosides. The current research investigates the possible effect of ginsenosides on iNOS as a possible explanation of the reported healing benefits of Panax ginseng. Using an aqueous extract of Panax ginseng with a standardized ginsenoside content, the researchers investigated its molecular action on iNOS in a murine microphage-like cell line. The cell line is known as RAW 264.7 and is derived from mice. As the research focuses squarely on the molecular reaction of an aqueous solution of Panax ginseng on iNOS, the results would indicate similar results on a human cell line. The researchers also clarify their choice of studying murine macrophages. Macrophages are generally associated with NO production, and detecting increases in NO output is easier with murine macrophages than with other cell lines.

The Panax ginseng used for the current study was a commercially-available powdered form manufactured by the company Nature's Way. The use of Panax ginseng in its whole root form as it is most often used in traditional Chinese medicine may therefore yield different effects than the current research, which not only used a powdered form of the root but also a fractionation. It is highly likely that the effects of Panax ginseng on the human body derive not merely from ginsenosides but from other compounds in the herb as well.

Results were based on measuring NO levels. A Western blot analysis was used. A protein determination test was also undertaken to determine the effects of ginsenosides on protein production. The authors do not clearly discuss the implications of protein expression on the immune response.

Increasing amounts of Panax ginseng were added to the RAW 264.7 cells and NO levels did increase in turn. The researchers controlled for intervening variables such as a possible Griess reaction or bacterial contamination that might induce iNOS. Furthermore, the researchers were able to isolate specific components in the ginseng aqueous solution that were responsible for the NO production: polysaccarides. The authors also note that macrophages are instrumental in the immune response: they produce NO; NO in turn acts as an antimicrobial and antiviral compound. A sustained NO production may be a key to preventing serious disease.

Ginseng is used in Traditional Chinese Medicine as a tonic herb, one that has an overall effect on preventing illness, enhancing immune response, and defending the body against pathogens. Prior research, listed in the Results section of the Friedl, et al. (2001) report, has substantiated the claims of traditional medicine. Research using aqueous solutions of Panax ginseng has also yielded results suggesting that the root enhances antibody formation. Oral administration of Panax ginseng in vivo studies also show promising results of the herb on stimulating the body's natural defenses especially against common respiratory infections.

The current research deepens the body of literature already extant on Panax ginseng. By isolating the polysaccarides as the compounds that are mainly essential for nitric oxide stimulation in cells, the researchers potentially contribute to the growing compendium of medical literature addressing the potential of natural healing interventions to complement or replace pharmaceuticals. The current research also isolates the main reason why Panax ginseng is effective in enhancing immunity: ginsenosides stimulate the production of NO and NO is associated with enhanced natural defenses against pathogens. The results also depended on dose: the greater the exposure of the murine macrophages to the ginsenosides, the greater the production of NO.