<i>Thymus vulgaris</i> Essential Oil Protects Zebrafish against Cognitive Dysfunction by Regulating Cholinergic and Antioxidants Systems

• Main Authors: Luminita Capatina, Elena Todirascu-Ciornea, Edoardo Marco Napoli, Giuseppe Ruberto, Lucian Hritcu, Gabriela Dumitru
• Format: Article
• Language: English
• Published: MDPI AG 2020-11-01
• Series: Antioxidants
• Subjects: <i>Thymus vulgaris</i>; essential oil; scopolamine; anxiety; memory; oxidative stress
• Online Access: https://www.mdpi.com/2076-3921/9/11/1083

<i>Thymus vulgaris</i> L. is an aromatic herb used for medicinal purposes such as antimicrobial, spasmolytic, antioxidant, anti-inflammatory, antinociceptive, antitumor, and may have beneficial effects in the treatment of Alzheimer’s disease. The present study aimed to investigate whether <i>Thymus vulgaris</i> L. essential oil enhances cognitive function via the action on cholinergic neurons using scopolamine (Sco)-induced zebrafish (<i>Danio rerio</i>) model of memory impairments. <i>Thymus vulgaris</i> L. essential oil (TEO, 25, 150, and 300 µL/L) was administered by immersion to zebrafish once daily for 13 days, whereas memory impairment was induced by Sco (100 μM), a muscarinic receptor antagonist, delivered 30 min before behavioral tests. Spatial memory was assessed using the Y-maze test and novel object recognition test (NOR). Anxiety and depression were measured in the novel tank diving test (NTT). Gas Chromatograph-Mass Spectrometry (GC-MS) analysis was used to study the phytochemical composition of TEO. Acetylcholinesterase (AChE) activity and oxidative stress response in the brain of zebrafish were determined. TEO ameliorated Sco-induced increasing of AChE activity, amnesia, anxiety, and reduced the brain antioxidant capacity. These results suggest that TEO may have preventive and/or therapeutic potentials in the management of memory deficits and brain oxidative stress in zebrafish with amnesia.