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Ginsenoside-Rh1 and Rh2 inhibit the induction of nitric oxide synthesis in murine peritoneal macrophages
Abstract:
The effects of ginsenoside-Rh1 and Rh2 in the induction of nitric oxide (NO) synthesis by IFN-gamma plus LPS were investigated using murine peritoneal macrophages. The NO production from rIFN gamma plus LPS-treated macrophages was markedly reduced by ginsenoside-Rh1 or Rh2 in a dose dependent manner, but had no inhibitory effects by ginsenoside-Rb1, Rc or Re. In addition, treatment of the cells with ginsenoside-Rh2 6 hr before the stimulation with IFN-gamma plus LPS showed more inhibitory effect than the treatment with ginsenoside-Rh2 6 hr after or simultaneously with the stimulation with IFN-gamma plus LPS in the NO production. Ginsenoside-Rh2 also effectively inhibited IFN-gamma induced NO production when the cells were treated with IFN-gamma 6 hr after the treatment with ginsenoside-Rh2. Our findings suggest that this phenomenon might be caused by inhibition of priming signal such as IFN-gamma for the synergistic induction of NO synthesis.
Insights
Ginsenoside-Rh1 and Rh2 significantly inhibit nitric oxide (NO) production in macrophages stimulated with IFN-gamma and LPS. This suggests these compounds may interfere with the priming signals required for NO synthesis.
Area of Science:
- Immunology
- Pharmacology
Background:
- Nitric oxide (NO) plays a crucial role in immune responses.
- Interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS) synergistically induce NO synthesis in macrophages.
- Ginsenosides are active compounds derived from Panax ginseng with various biological activities.
Purpose of the Study:
- To investigate the effects of specific ginsenosides, Rh1 and Rh2, on NO synthesis induced by IFN-gamma plus LPS in murine peritoneal macrophages.
- To determine the dose-dependent effects and optimal timing of ginsenoside treatment for NO inhibition.
Main Methods:
- Murine peritoneal macrophages were treated with IFN-gamma and LPS.
- Ginsenoside-Rh1, Rh2, Rb1, Rc, and Re were added at various concentrations and time points.
- Nitric oxide production was measured.
Main Results:
- Ginsenoside-Rh1 and Rh2 markedly reduced NO production in a dose-dependent manner.
- Ginsenoside-Rb1, Rc, and Re showed no significant inhibitory effects.
- Pre-treatment with ginsenoside-Rh2 before IFN-gamma plus LPS stimulation yielded greater inhibition than simultaneous or post-treatment.
- Ginsenoside-Rh2 also inhibited IFN-gamma-induced NO production when administered after IFN-gamma.
Conclusions:
- Ginsenoside-Rh1 and Rh2 effectively inhibit NO synthesis induced by IFN-gamma plus LPS.
- The inhibitory effect of ginsenoside-Rh2 is timing-dependent, suggesting interference with priming signals.
- These findings indicate a potential mechanism for ginsenosides in modulating inflammatory responses via NO production inhibition.