Abstract

Four types of extracts were prepared from Melia azedarach L. (Meliaceae) leaves: Aqueous, potassium phosphate buffer (pH 7.2), hydroethanolic solution 70:30 and hydroethanolic solution 50:50. Different concentrations of these extracts were investigated for the effect on butyrylcholinesterase (BuChE, EC 3.1.1.8) activity in homogenates rat livers. The introduction of M. azedarach extracts in the reaction mixture produced a variety of inhibitions (> 45 to 100%), independent on its concentration (0.5 to 2.0 mg.ml^-1) and extract type. A clear explanation for this interaction between M. azedarach and active site of butyrylcholinesterase is still missing. The UV-VIS (200 to 400 nm) absorption spectrum and the phytochemicals tests of the extracts show diversity of compounds including flavonoids, a known inhibitor of butyrylcholinesterase. On the other hand, decreased butyrylcholinesterase activity in homogenates rat livers was not correlated with flavonoids content, suggesting that other compounds may have contributed to the inhibitory capacity of this plant.  

Key words: Enzymatic activity, flavonoids, medicinal plants.