Other in vivo studies revealed that quercetin decreased extracellular β-amyloidosis, tauopathy, astrogliosis, and microgliosis in the hippocampus and amygdala of 3xTg-AD mice, decreasing the number of paired helical filaments (PHF), Aβ levels, and BACE1-mediated cleavage of APP [171,172]. Here, BACE1 is linked to Alzheimer disease.