Honokiol inhibits the inflammatory reaction during cerebral ischemia reperfusion by suppressing NF-κB activation and cytokine production of glial cells

► Honokiol inhibits brain edema and BBB injury. ► Honokiol suppresses NF-κB activation. ► Honokiol reduces NO production in cultured glial cells. ► Honokiol inhibits TNF-α production in cultured glial cells. ► Honokiol decreases RANTES production in cultured glial cells. This study was designed to investigate the effects of honokiol, a neuroprotective agent, on cerebral edema in cerebral ischemia reperfusion (IR) mice and its mechanism of anti-inflammation. Honokiol (0.7–70μg/kg) significantly reduced brain water contents and decreased the exudation of Evans blue dye from brain capillaries in cerebral IR mice. Honokiol (0.1–10μM) significantly reduced the p65 subunit level of NF-κB in the nucleus of primary culture-microglia. It (0.01–10μM) evidently reduced nitric oxide (NO) level in the microglia culture medium and in the microglia and astrocytes coculture medium. Honokiol (0.01–10μM) significantly decreased the level of TNF-α in the microglia medium or coculture cell medium. Honokiol (10μM) decreased the level of Regulated upon Activation Normal T-cell Expressed and Secreted (RANTES/CCL5) protein in medium of microglia or astrocytes. In conclusion, Honokiol has a potent anti-inflammatory effect in cerebral ischemia-reperfusion mice and this effect might be attributed to its inhibition ability on the NF-κB activation, consequently blocking the production of inflammatory factors including: NO, tumor necrosis factor-α (TNF-α) and RANTES/CCL5 in glial cells. These results provide evidence for the anti-inflammatory effect of honokiol for the potential treatment of ischemic stroke.