Cognitive- and memory-enhancing activity of Cinnamon (Cinnamomum zeylanicum) aqueous extract in lead acetate-exposed rats

Abstract

Background: Lead (Pb) exposure has been linked to reduced academic performance, lower IQ, cognitive and memory impairments, and other psychiatric conditions such as depression and anxiety. Natural antioxidants and dietary sources of phytochemicals, including Cinnamomum zeylanicum (CZ), have been investigated to possibly replace the current adverse reacting drugs used to treat Pb poisoning. Consequently, this study evaluated the activity of CZ against Pb-mediated neurotoxicity. Methods: Wistar rats were assigned into six groups (n = 8) namely: Control; Lead acetate (Pb; 100 mg kg−1 body weight [BW]); CZ-pre-treated groups (CZ1 [200 mg.kg−1 BW] + Pb and CZ2 [400 mg kg−1 BW] + Pb); and CZ-only groups (CZ1 and CZ2). After 28 days, neurobehavioral, antioxidant, lipid peroxidation, nitric oxide, and Pb concentration levels, as well as hippocampal and cerebral histology, were evaluated. Results: Findings showed a significant reduction (p < 0.05) in final body and whole brain weights, cognition, and memory impairments, dysregulation of antioxidant enzymes, lipid peroxidation, and elevated nitric oxide as well as high Pb concentrations in the hippocampus and cerebrum of Pb-exposed rats following comparison to the control and CZ pretreated rats. Histological findings revealed morphological alterations with vacuolated tissue architecture in the hippocampus and cerebrum of Pb-exposed rats while the rats pre-treated with CZ showed similar morphology to the control rats. Conclusion: Altogether, the findings showed that CZ was not toxic to the rats but protected against Pb toxicity, mediated possibly through its potent antioxidant, nitric oxide scavenging, and metal chelation activity.

Keywords

• Lead
• Cinnamomum zeylanicum
• Neurotoxicity
• Neuroprotection