Moringa oleifera lam. Leaf Extract Preserves Spatial Memory and Hippocampal Microstructure in Aluminium Chloride-Induced Neurotoxicity in Adult Wistar Rats

Aluminium is a widely available and subtly consumed metal, whose actions on human health include neurotoxicity and cognitive decline, among others. It is important to protect against these aluminium effects through antioxidants, as aluminium utilizes the oxidative pathway to exert its effect. Due to the abundance of antioxidants in Moringa oleifera (M. oleifera), this study investigated its neuroprotective potential against aluminium chloride (AlCl3)-induced hippocampal intoxication in Wistar rats. The phytochemical screening and toxicity (LD50) of M. oleifera leaf ethanol extract (MO) were evaluated. Thirty adult male Wistar rats (150–220 g) were then assigned into six groups (n = 5): control, AlCl3 (100 mg/kg), M. oleifera low dose (MOLD, 250 mg/kg), M. oleifera high dose (MOHD, 1,000 mg/kg), concomitant AlCl3 + MOLD, and AlCl3 + MOHD. These administrations were oral and lasted for 21 days. On day 22, spontaneous alternation behaviour (SAB) was tested in the T-maze, the animals sacrificed, and the brains processed for histology and immunoreactivity. The phytochemicals of MO included flavonoids, phenols, alkaloids, saponins, and tannins as the major constituents, while its LD50 was greater than 5,000 mg/kg. There was significantly (p < 0.05) less SAB, hippocampal cornu ammonis (CA) 3 chromatolysis, and decreased neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP) expressions in the AlCl3 group. Concomitant treatment with MOLD and MOHD did not significantly improve SAB, and NSE and GFAP expressions, but preserved Nissl distribution. MO protected the hippocampus against AlCl3 intoxication by improving SAB, and modulating Nissl distribution, NSE, and GFAP expressions, which supports its antioxidant potential.