Inhibitory Effect of Chaenomeles sinensis Fruit on Amyloid β Protein (25-35)-Induced Neurotoxicity in Cultured Neurons and Memory Impairment in Mice

The present study investigated an ethanol extract of Chaenomeles sinensis fruit (CSF) for possible neuroprotective effects on neurotoxicity induced by amyloid β protein (Aβ) (25-35) in cultured rat cortical neurons and also for antidementia activity in mice. Exposure of cultured cortical neurons to 10 μM Aβ (25-35) for 36 h induced neuronal apoptotic death. At 0.1-10 μg/ml, CSF inhibited neuronal death, elevation of intracellular calcium concentration ([Ca2+]i), and generation of reactive oxygen species (ROS) induced by Aβ (25-35) in primary cultures of rat cortical neurons. Memory loss induced by intracerebroventricular injection of mice with 15 nmol Aβ (25-35) was inhibited by chronic treatment with CSF (10, 25 and 50 mg/kg, p.o. for 7 days) as measured by a passive avoidance test. CSF (50 mg/kg) inhibited the increase of cholinesterase activity in Aβ (25-35)-injected mice brain. From these results, we suggest that the antidementia effect of CSF is due to its neuroprotective effect against Aβ (25-35)-induced neurotoxicity and that CSF may have a therapeutic role for preventing the progression of Alzheimer’s disease.