| Alzheimer’s disease (AD) is the most common type of dementia in the aging population. Causes of AD are the accumulation of amyloid plaques,neurofibrillary tangles, free radicals and the decline of acetylcholine in the brain. Nowadays natural compounds from plant sources have been used for AD treatment. In this study, 9 free radical scavenging plantmethanolextracts such as Allospondias lakonensis,Acalypha hispida,Ailanthus triphysa,Oxyceros horridus,Vernicia Montana, Euphorbia hirta,Homonoia riparia,Psychotria curviflora andTetrastigma erubescenswere investigated for their acetylcholinesterase inhibiting activity (AChI). Objective:To evaluate the AChI activityand to determine the phytochemical components of the 9 plant crude methanol extracts. Methods:The AChI activity were determined using microplate reader. Total alkaloid, total phenolic and total flavonoid contents of the crude extracts were quantified by spectrophotometric methods.Results:Among the 9 crude extracts, Homonoia ripariaextractshowed the highest AChI activity (59.13±2.11 %) at100 µg/ml. Eserine, apositive standard, showed AChI activity (98.80±1.44%) at the same concentration. For the phytochemical screening, Euphorbia hirta had the highest alkaloid content (21.69±6.36mg/g). Psychotria curviflora showed the highest flavonoid contentat 54.02±1.55mg/gwhile Acalypha hispidaexhibitedthe highest total phenolic content at 118.20±4.76mg/g. Conclusion:Homonoia ripariaextract demonstrated the highest AChI activity. Euphorbia hirtadisplayed the highest total alkaloid content, Psychotria curviflora showed the highest total flavonoid content andAcalypha hispidaexhibitedthe highest total phenolic content. |