Multiple sclerosis(MS)is a systemic inflammatory illness of the central nervous system that involves demyelinating lesions in the myelin-rich white matter and pathology in the grey matter.Despite signifi-cant advancements in drug research for MS,the dis-ease's complex pathophysiology makes it difficult to treat the progressive forms of the disease.In this study,we identified a natural flavonoid compound icariin(ICA)as a potent effective agent for MS in ameliorating the deterioration of symptoms including the neurological defi-cit score and the body weight in a murine experimental autoimmune encephalomyelitis(EAE)model.These improvements were associated with decreased demyelin-ation in the corpus callosum and neuron loss in the hippo-campus and cortex confirmed by immunohistochemistry analysis.Meanwhile,it was observed that the activation of microglia in cerebral cortex and hippocampus were inhibited followed by the neuroinflammatory cytokines downregulation such as IL-1β,IL-6 and TNF-α after ICA treatment,which was probably attributable to the sup-pression of microglial NLRP3 inflammasome activation.Additionally,molecular docking also revealed the binding force of ICA to NLRP3 inflammasome protein complexes in vitro.Taken together,our findings have demonstrated that ICA,as pleiotropic agent,prevents EAE-induced MS by improving demyelination and neuron loss,which inter-feres with the neuroinflammation via microglial NLRP3 inflammasome activation.