Flavanol-rich lychee fruit extract substantially reduces progressive cognitive and molecular deficits in a triple-transgenic animal model of Alzheimer disease

Effective treatment to prevent or arrest the advance of Alzheimer disease (AD) has yet to be discovered. We investigated whether Oligonol^R, an FDA-approved flavanol-rich extract prepared from lychee fruit and green tea, exerted beneficial effects relevant to AD in a triple transgenic male mouse model of AD (3×Tg-AD). At 9 months of age, untreated 3×Tg-AD mice vs. wild-type (WT) controls displayed cognitive deficits in behavioral assays and, at 12 months, elevated levels of hippocampal amyloid beta-protein (Aβ), amyloid precursor protein (APP), tau phosphorylation, and pro-inflammatory cytokines. 3×Tg-AD mice given Oligonol showed fewer cognitive deficits and attenuated pathological indices at 12 months. Oligonol treatment of 3×Tg-AD mice modulated expression of some critical brain proteins that involve multiple pathways relevant to mitochondrial dysfunction, proteasomal failure, endoplasmic reticulum (ER) stress and synaptic impairment. Together, these results demonstrate that continuous Oligonol treatment attenuates AD-like pathology and cognitive impairment of 3×Tg-AD mice and set the stage for clinical trials of this flavanol-rich plant extract in patients with early AD.