Consumption of Grape Seed Extract Prevents Amyloid-beta Deposition and Attenuates Inflammation in Brain of an Alzheimer's Disease Mouse

Polyphenols extracted from grape seeds are able to inhibit amyloid-beta (A beta) aggregation, reduce A beta production and protect against A beta neurotoxicity in vitro. We aimed to investigate the therapeutic effects of a polyphenol-rich grape seed extract (GSE) in Alzheimer's disease (AD) mice. APP(Swe)/PS1dE9 transgenic mice were fed with normal AIN-93G diet (control diet), AIN-93G diet with 0.07% curcumin or diet with 2% GSE beginning at 3 months of age for 9 months. Total phenolic content of GSE was 592.5 mg/g dry weight, including gallic acid (49 mg/g), catechin (41 mg/g), epicatechin (66 mg/g) and proanthocyanidins (436.6 mg catechin equivalents/g). Long-term feeding of GSE diet was well tolerated without fatality, behavioural abnormality, changes in food consumption, body weight or liver function. The A beta levels in the brain and serum of the mice fed with GSE were reduced by 33% and 44%, respectively, compared with the Alzheimer's mice fed with the control diet. Amyloid plaques and microgliosis in the brain of Alzheimer's mice fed with GSE were also reduced by 49% and 70%, respectively. Curcumin also significantly reduced brain A beta burden and microglia activation. Conclusively, polyphenol-rich GSE prevents the A beta deposition and attenuates the inflammation in the brain of a transgenic mouse model, and this thus is promising in delaying development of AD.