Protective effects of Angelica sinensis extract on amyloid β-peptide-induced neurotoxicity

The protective effects of alcohol extract from the root of Angelica sinensis (AS) on β-amyloid peptide (Aβ)-induced toxicity and the mechanism of these effects were investigated. Aβ is a pathological hallmark of Alzheimer's disease; it decreased viability of Neuro 2A cells in a concentration-dependent manner with IC₅₀ of 14.9 μM. AS extract resulted in dose-dependent anti-Aβ toxicity according to MTT assay. Reactive oxygen species (ROS) analysis revealed a significant production of hydrogen peroxide, decreased glutathione (GSH) levels and increased lipid peroxidation (TBARS value) in the Aβ-treated Neuro 2A cells. The Aβ-treated cells also showed a significant decline in the mitochondrial transmembrane potential (ΔΨm) and increase in the mitochondrial volume, and portions of the cytoplasm were sequestered by a membrane-bound vacuole. The malfunctions of Neuro 2A cells caused by Aβ were attenuated using AS extract. The AS extract protected cell viability against Aβ-induced oxidative damage (ROS, TBARS, and GSH contents) and rescued the ΔΨm levels in a dose-dependent manner: the dosages of 25, 50, 100, and 200 μg/ml recovered 77%, 87%, 102%, and 105% of ΔΨm, respectively. AS extract also recovered the enlarged mitochondria mass with dosages from 25 to 200 μg/ml. The results of this study demonstrated that AS extract possessed the activity to prevent the neurotoxicity induced by Aβ-associated oxidative stress, implying that AS has a potential role in the prevention of Alzheimer's diseases.