<i>Schinus terebinthifolius</i>Essential Oil Attenuates Scopolamine-Induced Memory Deficits via Cholinergic Modulation and Antioxidant Properties in a Zebrafish Model

Abstract

<i>Schinus terebinthifolius</i> is a plant well recognized for its therapeutic profile such as anti-inflammatory and antitumor activities, promoting antibacterial activity and antioxidant and antidiabetic properties. This study aimed at examining whether <i>Schinus terebinthifolius</i> memory-enhancing activities are mediated by cholinergic and brain antioxidant systems in a scopolamine zebrafish model. <i>Schinus terebinthifolius</i> essential oil (10, 25, and 50 <i>μ</i>L/L) was delivered to zebrafish by immersion in water for 8 days. Memory deficits were induced by scopolamine (100 <i>μ</i>M) administration. Zebrafish were divided into seven groups (<i>n</i> = 15/group): vehicle group, scopolamine (100 <i>μ</i>M) group, <i>Schinus terebinthifolius</i> essential oil groups (STF; 10, 25, and 50 <i>μ</i>L/L), the imipramine group (IMP; 20 mg/L, as the positive control in the NTT test), and the donepezil group (DP; 10 mg/L, as the positive control in the Y-maze test). Memory status was estimated by the novel tank diving test (NTT) and the Y-maze test and finally was validated by comparison with imipramine (20 mg/L) and donepezil (10 mg/L). Gas chromatography-mass spectrometry (GC-MS) was used to detect oil compounds. Brain levels of acetylcholinesterase (AChE) and antioxidant enzymes were measured. After being exposed to <i>Schinus terebinthifolius</i> essential oil, the scopolamine zebrafish exhibited an improvement of memory processes in the NTT and Y-maze tests. The essential oil attenuated the elevated level of AChE and brain oxidative stress. <i>Schinus terebinthifolius</i> essential oil was found to support memory formation through the inhibition of the AChE activity and decreasing oxidative stress in the scopolamine-treated zebrafish brains.