Demethyleneberberine, which is composed of a potential antioxidant structure, could penetrate the membrane of mitochondria and accumulate in mitochondria either in vitro or in vivo.Demethyleneberberine suppresses CYP2E1, hypoxia inducible factor α, and inducible nitric oxide synthase, which contributes to oxidative stress and restored sirtuin 1/AMP-activated protein kinase/peroxisome proliferator-activated receptor-γ coactivator-1α pathway-associated fatty acid oxidation in chronic ethanol-fed mice.