Nano-Honokiol ameliorates the cognitive deficits in TgCRND8 mice of Alzheimer’s disease via inhibiting neuropathology and modulating gut microbiota

•In the same content, Nano-HO could effectively enhance the bioactivity of HO remarkably and prolonged its circulation time in rats.•Nano-HO improved cognitive deficits in TgCRND8 mice.•Nano-HO suppressed neuroinflammatory response (TNF-α, IL-Iβ, IL-6) inhibited the activation of microglia, astrocyte and A-β plaque burdens in TgCRND8 mice.•Nano-HO ameliorated AD through regulating APP processing, preventing tau hyperphosphorylation and modulating JNK/CDK5/GSK-3β pathway.•Nano-HO regulated the composition and structure of gut microbiota to protect the gut microflora and its stability.