Modified TLC bioautographic method for screening acetylcholinesterase inhibitors from plant extracts.

The present work describes modifications to an existing TLC bioautographic method for detecting acetylcholinesterase inhibitors from plant extracts. The basic principle of the method is that the enzyme converts 1-naphthyl acetate into naphthol which reacts with Fast Blue B salt to make a purple-colored background on the TLC plates. Inhibitors of acetylcholinesterases produced white spots on the background. Our modifications involve changes in the concentration of the enzyme, the reagents, and the time of the reaction. With these changes, the consumption of the enzyme was reduced by 85% and the detection limits were decreased remarkably.