Anti-inflammatory Activity of Salvianolic Acid B in Microglia Contributes to its Neuroprotective Effect

This study examined whether Salvianolic acid B (Sal B), a major active component of Chinese herb Radix Salviae Miltiorrhizae, may exert an anti-inflammatory effect in microglia and may be neuroprotective by regulating microglial activation. Our results showed that Sal B significantly reduced the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and reactive oxygen species (ROS) induced by lipopolysaccharide (LPS) treatment in rat primary microglia in a dose-dependent manner. Sal B had no effects on ATP-dependent IL-1β release and interferon (IFN)-γ-induced NO production. Sal B also suppressed LPS-induced inducible nitric oxide synthase (iNOS), TNF-α, and IL-1β mRNA expression, which was accompanied by inhibiting transcription factor NF-κB activation. Sal B could protect neurons through inhibition of microglial activation in a microglia-neuron coculture system. In conclusion, these data demonstrate that anti-inflammatory activity of Sal B in microglia contributes to its neuroprotective effect and suggest that it may be useful for preventing microglia-mediated neuroinflammation.