A study on inhibitory effect of ethanolic extract of the Pistacia lentiscus on acetylcholinesterase activity

Changes of the enzyme acetylcholinesterase are involved in pathogenesis of different nervous disorders including Alzheimer’s disease. This research work was conducted to evaluate the inhibitory effect of Pistacia lentiscus ethanolic extract on acetylcholinesterase activity.
Activity of the enzyme acetylcholinesterase (AChE) was measured by Ellman method, using scale. Then, Lineweaver Burk plot was used to calculate Km, Vmax and Ki. In all phases, the enzyme’s concentration was constant and its activity was measured at six different concentrations of acetylthiocholine (5, 10, 15, 20, 25 and 30 mM) at room temperature (25 °C) and based on the optical absorption at 412 nm wavelength. Experiments were conducted in the presence of various concentrations of physostigmine and also Pistacia lentiscus (2, 4, 6, 8, and 10 ug/ml).
Ki of inhibitors were measured at different concentrations of acetylthiocholine (5, 10, 15, 20, 25 and 30 mM) and also in the presence of various concentrations of physostigmine and Pistacia lentiscus (2, 4, 6, 8, and 10 ug/ml). IC50 of physostigmine and Pistacia lentiscus were determined as 2.9 and 6.5 μg/ml, respectively.
Since lower levels of Ki and IC50 indicate higher inhibitory effects on the enzyme, therefore, results show that physostigmine is a stronger inhibitor than Pistacia lentiscus.