Preliminary Study On Screening Anti-Alzheimer Natural Acitive Ingredients

The methods of high-throughput screening assay for acetylcholinesterase inhibitory activity and1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging were created in this study, according to two possible pathogenic mechanisms of AD:Cholinergic damage and free radical damage. This study was to search active ingredients which possessed significant anti-oxidant and anti-acetylcholinesterase activities for providing the way to treat Alzheimer.First of all, The method of the high-throughput screening assay for acetylcholinestera-se inhibitory activity was created, sixty-six different natrual ingredients were filtered. The results showed four ingredients had significant acetylcholinesterase inhibitory activities, they were the water extract of Ampelopsis grossedentata and its main active compound Dihydromyricetin, the total saponins in Polygala tenuifolia Willd and its alkaline hydrolysis product. The IC50values of them were451.11±21.09μg/ml,495.46±47.05μg/ml,31.82±2.05μg/ml,286.12±1.17μg/ml respectively. Besides, Under the concentration of0.25mg/ml, the acetylcholinesterase inhibition rates of Dihydromyricetin’s structure similar compounds, Myricetin and Myricitrin, were30.66%±4.05%,38.48%±1.98%respectively.Then, the method of high-throughput screening assay for1,1-diphenyl-2-picrylhydraz-yl (DPPH) free radical-scavenging was created. Dihydromyricetin, Myricetin, Myricitrin, the water extract of Ampelopsis grossedentata, and the mainly parts they exist were all investigated, and TLC method was also used in order to search for the ingredients which had the significant antioxidant activities. The result showed the DPPH free radical scaveng-ing activity of Dihydromyricetin was significant, the IC50value were10.7μg/mL, even stronger than postive drugs Vc (14.69μg/ml) and Rutin (31.32μg/ml).Finally, the acetylcholinesterase inhibitory activities of Myricetin, Myricitrin and Dihydromyricetin were not stable. Comparing to Myricetin and Myricitrin, the stability of Dihydromyricetin was better. These results may related to their structures, The stability of Myricitrin was studied, The solution of Myricitrin should be kept under neutral and weak acidity, at cold or room temperature, and preventing from metal ions.In view of this study’s results, Dihydromyricetin could be developed as the natrual active ingredient of the anti-Alzheimer’s drugs because of its significant acetylcholinestera-se inhibitory activity and1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical-scavenging activity.