Brain acetylcholinesterase activity and the protective effect of Gac fruit on scopolamine-induced memory impairment in adult zebrafish

Gac fruit (Momordica cochinchinensis) belongs to the Cucurbitaceae family. This study aimed to investigate the anti-memory impairment effect of Gac fruit aril extract and brain acetylcholinesterase activity in adult zebrafish (Danio rerio). The behavioral test was performed using a color-biased appetite conditioning T-maze test and an inhibitory avoidance test to evaluate memory performance. The time spent in the green arm in the T-maze test was recorded, and latency time was recorded in the inhibitory avoidance test. Brain acetylcholinesterase (AChE) enzyme activity was measured using a 96-well microplate reader based on Ellman's method. Zebrafish that received rivastigmine and Gac extract had significantly increased time spent in the green arm and latency time when compared to the SCO group. Zebrafish that received rivastigmine and Gac fruit extract at 200 mg/kg had lower AChE activity than the SCO groups; however, there were no statistically significant differences between the groups. These findings suggest that Gac fruit extract has anti-memory impairment activity and may be beneficial for the development of health products to prevent Alzheimer’s disease.