Effect of coenzyme Q10 and/or epigallocatechin gallate on memantine-treated amnesia model in rats

Abstract

Background Alzheimer’s dementia is a progressive, fatal neurodegenerative disease that manifests as a disintegration of perception and memory. Objectives The current study evaluated the possible therapeutic effect of coenzyme Q10 (CoQ10) and/or epigallocatechin-3-gallate (EGCG) combined with memantine on scopolamine-induced amnesia in rats by evaluating the behavioral, biochemical, and histopathological changes. Materials and methods Rats were randomly allocated to 11 groups, each of which contained 16 rats. Six rats were used for biochemical tests, while ten rats were used for behavioral and histological examinations. Two behavioral assessments were conducted: an object-recognition test and a conditioned-avoidance test. The dopamine (DA) content of brain tissues was determined, as well as oxidative stress markers, such as superoxide dismutase, lipid peroxide end product malondialdehyde, and reduced glutathione. Besides, the activity of acetylcholine esterase (AchE), total antioxidant capacity, and inflammatory markers, such as tumor necrosis factor-alpha and interleukin-one beta, were determined in serum. Furthermore, histological examinations of whole-brain tissues were made. Results Scopolamine-treated rats were administered memantine at a dose of 20 mg/kg, coenzyme Q10 at a dose of 10 mg/kg, and EGCG at a dose of 10 mg/kg, individually or in combination, resulting in an enhancement of cognitive impairment in the condition-avoidance and object-recognition tests, as well as an improvement in all oxidative stress biomarkers, inflammatory biomarkers, and histological examination. Conclusion Rats were administered memantine and pretreated by the combination of CoQ10 and EGCG, resulting in potentiating the memantine action in scopolamine-induced amnesia in rats. The improvement in cognitive memory could be due to the synergistic effect of these drugs by decreasing AchE activity, DA level, anti-inflammatory, and antioxidant effects.