Quercetin enrich diet during the early-middle not middle-late stage of alzheimer's disease ameliorates cognitive dysfunction.

The aim of this study was to evaluate the protective effects of dietary flavonoid quercetin against Alzheimer's disease (AD) and detect the explicit administration of quercetin in early-middle or middle-late stage of AD pathology could play the effect as well as its mechanism of action. In this study, APP/PS1 mice were used to investigate cognitive impairment and related pathologies. The results showed that quercetin enrich diet could play an ameliorated pathology development of AD in APP/PS1 mice. And then we next determined administration of quercetin in early-middle and middle-late stage of AD pathology, which exerted that only quercetin enrich diet during the early-middle stage of AD pathological development period ameliorates cognitive dysfunction and the protection effect was mainly related to increased Aβ clearance and reduced astrogliosis. These findings suggest a possible new protective role for dietary flavonoids on AD. This new role might expand the preventive and/or therapeutic use of AD in conditions.