Ginsenoside interactions with ginseng polysaccharides on iNOS expression and nitric oxide production in murine macrophage (RAW 264.7) cells

Abstract

Many of ginseng's medicinal effects may be related to the actions of its ginsenoside and polysaccharide components. The focus of this study was to examine potential interactions between ginsenosides and ginseng polysaccharides in the ability of ginseng to alter nitric oxide (NO) production using murine macrophage cells (RAW 264.7). Cells were treated with either ginseng extract (GE), ginsenosides, or ginseng polysaccharides (PS). After 12hr or 24hr of treatment, both GE and PS significantly induced nitric oxide (NO) release (p<0.01). Ginsenosides Rb1 and Rd had no effect on NO release at any time point. However, co-treatment with Rb1 or Rd inhibited PS-induced NO release. After 12hr and 24hr, there was also a significant increase in expression of iNOS mRNA and protein by PS in RAW cells. Treatment of RAW cells with ginsenosides Rb1 and Rd inhibited the PS-induced expression of mRNA, with Rb1 producing a greater response. These data suggest that PS are responsible for ginseng's effects on iNOS and NO release. Although ginsenosides themselves do not affect iNOS expression or NO release, their ability to attenuate PS induction of NO production may explain why ginseng is less effective than PS in stimulating iNOS and NO. The production of nitric oxide by ginseng may be the link between reported American ginseng use and increased immune function. (Funded by NCI grant CA121074)