MAPT and Alzheimer disease: Another study supported that exosomes loaded with quercetin not only significantly enhanced the bioavailability of quercetin and its accumulation in the brain region in SD rats but also improved cognitive function in Alzheimer’s disease mice by inhibiting the formation of insoluble neurofibrillary tangles by reducing cyclin-dependent kinase five mediated phosphorylation of tau protein (Qi et al., 2020), indicating exosomal quercetin as a potent inhibitor of tau protein aggregation in Alzheimer’s disease.