Assessment of anticholinesterase activities and antioxidant potentials of Anisomeles indica relevant to the treatment of Alzheimer’s disease

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder, and the most predominant cause of dementia in the elderly. Traditionally Anisomeles indica (L.) Kuntze has widely been used as tonic to brain. Our aim is to investigate the cholinesterase inhibitory activities, and antioxidant properties of the plant extracts in the treatment of AD. The crude methanol extract was prepared by cold extraction method and four fractions namely petroleum ether, chloroform, ethyl acetate, and water fraction were assessed for acetylcholinesterase and butyrylcholinesterase inhibitory activity by the Ellman method, and their antioxidant properties were assessed by several assays including reducing power, scavenging of DPPH and hydroxyl radicals together with quantitative analyses of endogenous substances. Among the tested samples, ethyl acetate extract was found to demonstrate the highest inhibitory activity significantly against both acetylcholinesterase and butyrylcholinesterase enzymes with IC50 values of 176.02 and 143.78 mg/ml, respectively. Similarly, ethyl acetate extract exhibited the highest radical scavenging ability appeared to be comparable to the reference standard catechin used in this study. The IC50 values of the extract against DPPH and hydroxyl radical scavenging activity were 12.67 and 18.61 mg/ml respectively. Quantitative analyses displayed higher contents of phenolics and flavonoids (79.55 and 347.19 mg gallic acid equivalent/g dried extract respectively) in the ethyl acetate fraction. The results revealed that the ethyl acetate extract, possibly due to its phenolic compounds, exerts potential antioxidant and cholinesterase inhibitory activities which may be useful in the treatment of AD.