In-vitro Evaluation of Acetylcholinesterase and Butyrylcholinesterase Inhibitory Activities of Antlion Larvae Extracts

Antlion is used in traditional medicine by natives of the southern part of Nigeria particularly the Yorubas for memory enhancement. The progress made so far in the use of this organism as a memory booster lead to investigating the acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) (the key enzymes in the pathogenesis of Alzheimer's disease) inhibitory activities of methanolic and phosphate buffered saline (PBS) extracts. The activities of these enzymes were investigated using Ellman’s method. The kinetics of the inhibition patterns was also studied using eserine as the standard inhibitor. The concentration of the extract required for 50% inhibition (IC50) of the AChE was 49.00 ± 1.20 and 271.40 ± 0.10 µg/mL, for the PBS and methanolic extracts respectively, compared to Eserine with IC50 of 2.25 x 10-2 ± 0.15 x 10-2 µg/mL. Similarly, the IC50 for the BuChE was 66.30 ± 0.40 and 216.70 ± 1.10 µg/mL respectively, for the methanol and PBS extracts, compared to Eserine with IC50 of 1.10 ± 0.30 µg/mL. The pattern of inhibition of the BuChE in the presence of the extracts was non-competitive, while AChE exhibited non-competitive and competitive inhibitions for the methanolic and PBS extracts respectively. It is therefore evident that extracts of the antlion larvae contained cholinesterase inhibitors which might be binding to AChE and BuChE; with the PBS extract inhibitory activity towards AChE being more potent than the methanolic extract. Suggesting a beneficial effect in cognitive deficit and related dementia associated with Alzheimer’s disease.