Neuroprotective effects of extracts from anti-aging chinese medicine Lycium Barbarum (Gou-Qi-Zi)

Abstract

Recent findings demonstrated that extracts from Lycium barbarum (Gou-Qi-Zi) exhibit anti-aging effects. It is hypothesized that these extracts exhibitneuroprotective effects against toxins in aging-related neurodegenerativediseases. In this study, we aim to investigate whether extracts fromL. barbarum have neuroprotective effects against beta-amyloid (Ab) peptidestoxicity. Rat cortical neurons exposed to Ab peptides resulted in apoptosisand subsequent necrosis. Pretreatment of aqueous or alkaline extractssignificantly reduced the release of lactate dehydrogenase. In addition, theyattenuated Ab peptide-induced caspases-3 and -2. While the aqueous extractelicited a typical dose-dependent neuroprotective effect, the alkaline extractshowed bi-phasic responses. Potential therapeutic window of using aqueousextract was wider than that of a well-known Western medicine LiCl. We havefurther examined the underlying mechanisms of neuroprotection. Pretreat-ment of aqueous extract markedly reduced the Ab peptide-stimulatedphosphorylation of JNK-1 and its substrates c-Jun-I and c-Jun-II. Takentogether, we have proved our hypothesis by showing neuroprotective effectsof the extracts from L. barbarum. Since Ab neurotoxicity plays significantroles in aging-related Alzheimer’s disease (AD), extracts from L. barbarummay open a new therapeutic window for the prevention of AD.