PPARGC1A and Alzheimer disease: In the Aβ1–42-induced AD model in vitro and in vivo, this study for the first time shows: 1) DG exerts neuroprotective effects and improves cognitive impairment; 2) DG rescues mitochondrial dysfunction and inhibits oxidative stress; and 3) DG increases the expression of PGC-1α, which might contribute to the neuroprotection of DG.