Protective effect of n-butanol extract from Alpinia oxyphylla on learning and memory impairments.

Alzheimer's disease (AD) is one of the major neurological diseases of the elderly. How to safely and effectively remove the toxic Aβ42 peptide through blood-brain barrier (BBB) is considered to be an effective method for the prevention and treatment of AD. The compounds whose molecule weight is less than 400 Da and the number of hydrogen bonding is less than 10 are more likely to permeate BBB. In our previous study, we have several small molecule compounds which are isolated from n-butanol (NB) extract of Alpinia oxyphylla that are similar with this kind of compounds This study explored the neuroprotective effects of the NB significantly protected against learning and memory impairments induced by Aβ(1-42) in Y-maze test, active avoidance test and Morris water maze test. Besides, NB (180 mg/kg, 360 mg/kg) was able to attenuate the neuronal damage and apoptosis in the frontal cortex and hippocampus in mice. In addition, the inhibition of β-secretase and the level of Aβ(1-42) are also involved in the action mechanisms of NB in this experimental model. This study provided an experimental basis for clinical application of A. oxyphylla Miq. in AD therapy.