3.8. Antiacetylcholinesterase Assay

The acetylcholinesterase (AChE) inhibitory assay was performed by a modified Ellman method described by Rijo et al. [24]. A sample of the prepared aqueous extract was added to an acetylcholinesterase solution in a buffer of pH 8. After incubation, a solution of acetylcholine and Ellman reagent were added and the absorbance was measured at 405 nm when the reaction reached equilibrium. A control reaction was carried out using the buffer as a replacement for the extract, and it was deemed to have 100% activity. As a positive control, 3 µM tacrine was used.

All assays were performed in triplicate, and the inhibition percentage was determined using the following equations, Equations (2) and (3).

Equation (2) determines the AChE velocity reaction of the control (ΔAbs_405nm/min), which should be in the linear range.

Equation (3) determines the percentage inhibition by the aqueous extract.