An aporphine alkaloid from Nelumbo nucifera as an acetylcholinesterase inhibitor and the primary investigation for structure-activity correlations

摘要

N-methylasimilobine (1), a new-found strong acetylcholinesterase (AChE) inhibitor, along with two weakly active aporphine alkaloids, nuciferine (2) and nornuciferine (3) were separated from Nelumbo nucifera. N-methylasimilobine (1) inhibited 50% of AChE activity at the concentrations of 1.5±0.2 μg mL -1 when the standard IC 50 value of Physostigmine was 0.013±0.002 μg mL -1. The mode of AChE inhibition by 1 was reversible and non-competitive. In addition, molecular modelling was performed to explore the binding mode of inhibitor 1 at the active site of AChE.