Rosmarinus officinalis Essential Oil Improves Scopolamine-Induced Neurobehavioral Changes via Restoration of Cholinergic Function and Brain Antioxidant Status in Zebrafish (Danio rerio)

Rosmarinus officinalis L. is a traditional herb with various therapeutic applications suchas antibacterial, antioxidant, anti-inflammatory, antidepressant, and anticholinesterase activities,and can be used for the prevention or treatment of dementia. In the present study, we tested whetherRosmarinus officinalis L. could counteract scopolamine-induced anxiety, dementia, and brain oxidativestress in the zebrafish model and tried to find the underlying mechanism. Rosmarinus officinalis L.essential oil (REO: 25, 150, and 300 µL/L) was administered by immersion to zebrafish (Danio rerio) oncedaily for eight days while scopolamine (100 µM) treatment was delivered 30 min before behavioraltests. The antidepressant and cognitive-enhancing actions of the essential oil in the scopolaminezebrafish model was measured in the novel tank diving test (NTT) and Y-maze test. The chemicalcomposition was identified by Gas chromatograph-Mass spectrometry (GC-MS) analysis. The brainoxidative status and acetylcholinesterase (AChE) activity was also determined. REO reversedscopolamine-induced anxiety, memory impairment, and brain oxidative stress. In addition, a reducedbrain AChE activity following the administration of REO in scopolamine-treated fish was observed.In conclusion, REO exerted antidepressant-like effect and cognitive-enhancing action and was able toabolish AChE alteration and brain oxidative stress induced by scopolamine.