Quercetin contained in Eucommia ulmoides decreased the expression levels of p-ERK, p-JNK, and p-p65 in okadaic acid-induced hippocampal neurons and reduced the expression levels of amyloid-β1-42 and phosphorylation tau protein in aged triple transgenic Alzheimer's disease model mice [70, 71]. This evidence concerns the gene MAPK8 and Alzheimer disease.