Anti-inflammatory mechanism of ginseng saponins in activated microglia

In the present study, we investigated the effect of ginseng extract (KRG) and total saponins (GTS) on microglial activation. KRG and GTS inhibited LPS-induced expression of iNOS, MMP-9 and proinflammatory cytokines in microglial cells. Suppression of microglial activation by ginseng was also observed in the mouse brain inflamed by LPS. Furthermore, KRG and GTS significantly suppressed NF-kappaB and MAP kinase activities, which are upstream signaling molecules in inflammation. Among the individual ginsenosides tested, Rh2, Rh3 and compound K significantly inhibited LPS-induced iNOS and cytokine expressions. Therefore, the inhibition of microglial activation by ginseng saponins may a good potential therapeutic modality for neurodegenerative diseases.