Effects of Rosmarinus officinalis essential oil in memory formation and relieving brain oxidative stress in zebrafish scopolamine model

Aims: This study was undertaken in order to evaluate the anxiolytic, antiamnesic and antioxidant potential of the Rosmarinus officinalis essential oil (25,150 and 300 µl/L) using a scopolamine (100 µM) - induced a zebrafish model of dementia. Methods: The essential oil chemical composition was evaluated by GC-MS. Also, the anxiety-like behavior and memory formation were assessed by novel tank diving test (NTT), the Y-maze and the T-maze tests. The essential oil (25,150 and 300 µl/L) was administered by immersion for 61 days period. Also, the scopolamine (100 µM) was delivered by immersion 30 minutes before the behavioral tests to induce anxiety and mild dementia. A Logitech HD Webcam C922 Pro Stream camera recorded zebrafish behavior, and the videos analyzed using ANY-maze®software (Stoelting CO, USA). The in vivo antioxidant effects of the essential oil were determined through antioxidant enzymes activity (SOD. CAT and GPX) levels, total content of reduced GSH and lipid peroxidation products (MDA) from the brain homogenates. Also, the acetylcholinesterase activity was evaluated. Results: Our data demonstrated that the essential oil reverted the anxiety and amnesic responses as a result of scopolamine administration that parallel with decreasing of brain oxidative stress and lipid peroxidation products. Conclusions: In summary, our essential oil could be considered as a good candidate for improving memory via antiacetylcholinesterase inhibitory effect and reducing brain oxidative stress.