In vivo and in vitro studies have found that Icariin II reduces neuronal damage in AD model animals by activating the BDNF/TrkB/CREB signaling pathway (Liu et al., 2018) and alleviates LPS-induced neuroinflammation by inhibiting the TLR4/MyD88/NF-κB pathway (Zhou et al., 2019). Here, TLR4 is linked to Alzheimer disease.