BDNF and Alzheimer disease: Previous studies have confirmed that crude extract of YQF can effectively improve spatial learning and memory abilities of aged rats and APP/PS1 model mice, improve histopathological and morphological characteristics in rats, significantly increase acetylcholine and IL-10 levels, reduce the expression of inflammatory factors such as TNF-α and IL-6, and activate the BDNF/TrkB pathway to exert neuroprotective effects, suggesting that it has good clinical prospects in the treatment of AD (Yang et al., 2019; Ma et al., 2020).