Evaluating the impact of eugenol on paraquat-altered motor, anxiety, memory, and cognitive abilities in Wistar rats

Many bioactive substances, such as eugenol, which is the most active and comprises about 90-98 percent of the components of Syzygium aromaticum L. (clove), are used traditionally to treat several ailments, including but not limited to respiratory conditions, digestive disorders, elimination of cold, and easing pain by the Ayurveda, Middle Easterners, Africans, as well as the Chinese.

To ascertain the role of eugenol in paraquat-altered motor, cognition, and memory in Wistar rats.

40 male Wistar rats were obtained from the AEFUNAI animal house, acclimatized for fourteen days, and assigned into five groups of eight rats. Group A (control) received water and fed, Groups B, C, D, and E received 10 mg/kg of Paraquat (PQ), and thereafter Groups C, D, and E were treated with 200, 400, and 600 mg/kg of eugenol, respectively, for 14 days. Anxiety, memory, and cognition were measured using open-field test, T-Maze, and novel object recognition test. Acetylcholine, oxidative stress, antioxidants, alpha-synuclein, and Tau proteins were estimated using brain homogenates.

There was a significant increase in contextual fear and anxiety in the PQ-untreated group due to neuronal loss in the brain histoarchitecture, resulting from increased oxidative stress and reduced antioxidants. Line crossings were reduced significantly in the PQ-untreated group and were significantly increased in the eugenol-treated groups (p < 0.05). Paraquat-induced neurological changes lead to reduced cognitive flexibility, attention deficits, and processing speed. Microscopically, the CA1, CA3, and DG areas presented alterations such as necrosis, hemorrhages, pyknosis, and cell deaths.

The findings suggest that eugenol is a good antioxidant capable of restoring motor and cognitive abilities in rats administered with paraquat.