Puerarin protects against β-amyloid-induced microglia apoptosis via a PI3K-dependent signaling pathway.

Puerarin extracted from Radix puerariae is well-known for its anti-oxidative and neuroprotective activities. In this study, we investigated the protective effect of puerarin on amyloid-β protein (Aβ)-induced cytotoxicity and its potential mechanisms in BV-2 and primary microglial cells. We found that pretreatment with puerarin afforded protection against Aβ-induced cytotoxicity through inhibiting apoptosis in BV-2 and primary microglial cells. This result was also confirmed by the activated caspase-3 assay. Phospho-Akt and Bcl-2 expression increased after pretreatment with puerarin in BV-2 and primary microglial cells exposed to Aβ, whereas Bax expression and cytochrome c release decreased. In addition, puerarin treatment prevented the loss of mitochondrial membrane potential and reactive oxygen species production. Interestingly, these effects of puerarin against Aβ insult were abolished by LY294002, an inhibitor of PI3K phosphorylation. Taken together, these findings suggest that puerarin prevents Aβ-induced microglial apoptosis via the activation of PI3K/Akt signaling pathway, and might be a potential preventive or therapeutic agent for Alzheimer's disease.