Improvement in Cognition, Memory and Hippocampal CA1 microstructure in Aluminium Chloride-exposed Rats Following Pretreatment with Aqueous <i>Psidium guajava</i> Leaf Extract

Abstract

Reports indicate that humans are commonly exposed to aluminium (Al) to the extent that neuronal death may occur. However, studies  show that antioxidant sources can inhibit the toxic effects of Al. Psidium guajava, a traditional plant known for its diverse medicinal  properties, is reported to be a potential source of natural antioxidants. Hence, this study investigated the activity of aqueous Psidium  Guajava leaf extract (APGE) against AlCl₃-induced neurotoxicity. Thirty Wistar rats were divided into six equal groups as follows: Group A  (Control) received 1 ml H₂O/day, Group B received 100 mg/kg body weight (BW)/day of AlCl₃ only, Group C received 200 mg/kg BW/day  of APGE and 100 mg/kg BW/day of AlCl₃, Group D received 400 mg/kg BW/day of APGE and 100 mg/kg BW/day of AlCl₃, Group E received  200 mg/kg BW/day of APGE only and Group F received 400 mg/kg BW/day of APGE only, for twenty-eight days. Thereafter, the Novel  Object Recognition test was conducted and the rats were sacrificed to harvest the hippocampus for antioxidant enzymes activity, lipid  peroxidation, acetylcholinesterase and histological evaluation. Results showed a significant decline in the discrimination index and  antioxidant enzymes activity, in addition to elevated lipid peroxidation, increased acetylcholinesterase and severe hippocampal  alterations in AlCl₃-exposed rats when compared to the control. Conversely, pretreatment of Al-exposed rats with APGE mitigated the  effects induced by AlCl₃. Altogether, these findings showed that APGE protected against AlCl₃-induced hippocampal toxicity, consequently  providing novel research evidence on its therapeutic activity against Al.