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 herb promoting antioxidant, anti-inflammatory, antimicrobial and neuroprotective activities. We investigated the protective effects and 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 cognitive impairment. 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 300 lL/L, once daily for 13 days) reduced anxiety-like behavior and improved cognitive ability, which was confirmed by behavioral tests such as the novel tank-diving test (NTT), Y-maze test and novel 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 brain antioxidant status. Thus, OEO could be used as perspective sources of bioactive compounds, displaying valuable biological activities, with potential pharmaceutical applications