Analyzing Origanum vulgare ssp. hirtum (Lamiaceae) essential oil for neuroprotective potential against scopolamine-induced zebrafish (Danio rerio) model

Origanum vulgare ssp. hirtum has been used as medicinal herbpromoting antioxidant, anti-inflammatory, antimicrobial andneuroprotective activities. We investigated the protective effectsand the mechanism of O. vulgare ssp. hirtum essential oil (OEO)on cognitive impairment and brain oxidative stress in a scopolamine (Sco)-induced a zebrafish (Danio rerio) model of cognitiveimpairment. Our results showed that exposure to Sco (100 lM)leads to anxiety, spatial memory, and response to novelty dysfunctions, whereas the administration of OEO (25, 150, and 300lL/L, once daily for 13 days) reduced anxiety-like behavior andimproved cognitive ability, which was confirmed by behavioraltests such as the novel tank-diving test (NTT), Y-maze test andnovel object recognition test (NOR) in zebrafish. Additionally,Sco-induced brain oxidative stress and increasing of acetylcholinesterase (AChE) activity were attenuated by the administration of OEO. The gas chromatography-mass spectrometry(GC-MS) analyses were used to elucidate the OEO composition,being thymol (38.82%), p-cymene (20.28%), and c-terpinene(19.58%) as the main identified components. These findings suggested the ability of OEO to revert the Sco-induced cognitive deficits by restoring the cholinergic system activity and brainantioxidant status. Thus, OEO could be used as perspectivesources of bioactive compounds, displaying valuable biologicalactivities, with potential pharmaceutical applications