Repression of some cholinergic and monoaminergic enzymes by non-polar solvent extracts from Rosary Pea (Abrus precatorius)

Abstract

This study focused on the effects of four different solvents (ethanol, acetone, dichloromethane (DCM) and N-hexane) extractions of Abrus precatorius leaves on neurological enzymes [acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and monoamine oxidase (MAO)], which are markers of Alzheimer’s disease (AD), as well as the antioxidant [1,1-diphenyl-2 picrylhdrazyl] (DPPH) radical scavenging and ferric reducing antioxidant property (FRAP) potentials. The results revealed that acetone and N-hexane extracts had the highest AChE inhibitory effect having an EC₅₀ value of 0.28 and 0.27 mg/ml, respectively, with no significant difference, while ethanol (EC₅₀ = 0.61 mg/ml) extract had the least on BChE activity. Also, on MAO activity, acetone (0.24 mg/ml) and N-hexane (0.24 mg/ml) extracts had the highest inhibitory effect with no significant difference. The total phenol and flavonoid contents of the extracts ranged between 4.51 - 9.47 mg GAE/100 g and 0.03 - 0.41 mg QE/100 g respectively. All the extracts scavenged DPPH radical and possessed Fe reducing power. The inhibition of cholinesterases and MAO activities as well antioxidative potential of A. precatorius could be some of its possible mechanisms explore in folklore for the management of neurodegenerative diseases. However, in vivo and clinical studies should be carried out to ascertain these claims.