OBJECTIVE Brain inflammation plays an important role in the pathophysiology of brain ischemicstroke,psychiatric and neurological diseases.During brain inflammation,microglia cells are activated and show pro-inflammatory M1 and anti-inflammatory M2 phenotypes,producing neurotoxic molecules and neurotrophic factors,respectively.We have previously discovered a novel natural product compound 3c exhibiting antiinflammatory effects in microglia cells,but the underlying mechanisms and its beneficial effects on brain inflammation and brain ischemia are unknown.METHODS The gene expression of M1 markers and M2 markers was measured by RT-PCR.The AMPK phosphorylation level and M2 marker CD206 protein expression were determined by Western blotting.TNFαrelease was measured by ELISA.The gene knowdown was performed by the si RNA transfection experiment.The LPS-induced brain inflammation mouse model and transient middle cerebral artery occlusion(t MCAO)stroke model were used.RESULTS We found that compound 3c inhibited M1polarization and promoted M2 polarization in LPS-stimulated BV2 and primary microglia cells,and these effects are mediated by Ca MKKβ/AMPK/JNK signaling pathway.Furthermore,compound 3c prevented M1 gene expression and enhanced M2 gene expression in a mouse model of LPS-induced neuroinflammation,and reduced the LPS-induced sickness behavior.In addition,compound 3c significantly reduced infarct volume,improved the neurological deficit,and reduced neuroinflammation in rats with acute focal cerebral ischemia.CONCLUSION Our results indicate that natural product compound 3c suppresses microglia activation by promoting M2 polarization and may provide a novel therapeutic approach to treat brain ischemic stroke associated with enhanced brain inflammation. OBJECTIVE Brain inflammation plays an important role in the pathophysiology of brain ischemicstroke, psychiatric and neurological diseases. Brain tumor, microglia cells are activated and show pro-inflammatory M1 and anti-inflammatory M2 phenotypes, producing neurotoxic molecules and neurotrophic factors, respectively. have previously discovered a novel natural product compound 3c exhibiting antiinflammatory effects in microglia cells, but the underlying mechanisms and its beneficial effects on brain inflammation and brain ischemia are unknown. METHODS The gene expression of M1 markers and M2 markers was measured by RT-PCR. The AMPK phosphorylation level and M2 marker CD206 protein expression were determined by Western blotting. TNF reporter was measured by ELISA. The gene knowdown was performed by the si RNA transfection experiment. The LPS-induced brain inflammation mouse model and transient middle cerebral artery occlusion (t MCAO) stroke model were used. RESULTS We found that comp ound 3c inhibited M1polarization and promoted M2 polarization in LPS-stimulated BV2 and primary microglia cells, and these effects are mediated by Ca MKKβ / AMPK / JNK signaling pathway. Still further, compound 3c prevented M1 gene expression and enhanced M2 gene expression in a mouse model of LPS-induced neuroinflammation, and reduced the LPS-induced sickness behavior. In addition, compound 3c significantly reduced infarct volume, improved the neurological deficit, and reduced neuroinflammation in rats with acute focal cerebral ischemia. CONCLUSION Our results indicate that natural product compound 3c suppresses microglia activation by promoting M2 polarization and may provide a novel therapeutic approach to treat brain ischemic stroke associated with enhanced brain inflammation.