Ginsenoside Rg1 exerts synergistic anti-inflammatory effects with low doses of glucocorticoids in vitro.

Glucocorticoids (GCs) are usually used to treat inflammatory diseases. However, they cause severe and irreversible side effects, which limit the use of these compounds. Ginsenoside Rg1 had been demonstrated to possess anti-inflammatory and anti-cancer effects. The present study was designed to investigate whether Rg1 exhibits synergistic anti-inflammatory effects when combined with glucocorticoids. After stimulated by lipopolysaccharide (LPS), murine macrophagic RAW264.7 cells were treated with Rg1, corticosterone (Cort) or Rg1 and Cort. Then nitric oxide (NO), tumor necrosis factor-α (TNF-α) and glucocorticoid receptor (GR) expression were measured. The results showed that Rg1 or Cort could reduce the production of NO and TNF-α, and Rg1 dose-dependently up-regulated GR expression, while Cort dose-dependently down-regulated GR expression. The combination of low concentrations of Rg1 with Cort, which alone could not markedly inhibit the release of inflammatory factors, inhibited the secretion of NO and TNF-α in LPS-stimulated RAW264.7 macrophage cells, and up-regulated the expression of GR. The findings suggested Rg1 can synergize with glucocorticoid to enhance its anti-inflammatory effect.