Malibatol A regulates microglia M1/M2 polarization in experimental stroke in a PPARγ-dependent manner

Background: Activation of microglia plays a crucial role in immune and inflammatory processes after ischemic stroke. Microglia is reported with two opposing activated phenotypes, namely, classic phenotype (M1) and the alternative phenotype (M2). Inhibiting M1 while stimulating M2 has been suggested as a potential therapeutic approach in the treatment of stroke. Findings: In this study, we indicated that a novel natural anti-oxidant extracted from the Chinese plant Hopea hainanensis, malibatol A (MA), decreased the infarct size and alleviated the brain injury after mice middle cerebral artery occlusion (MCAO). MA inhibited expression inflammatory cytokines in not only MCAO mice but also lipopolysaccharide (LPS)-stimulated microglia. Moreover, treatment of MA decreased M1 markers (CD16, CD32, and CD86) and increased M2 markers (CD206, YM-1) while promoting the activation of nuclear receptor PPAR gamma. Conclusions: MA has anti-inflammatory effects in MCAO mice in a PPAR gamma-dependent manner, making it a potential candidate for stroke treatment.