Protective Effects of Bambara Nut (Vigna subterranea) Extract on Paracetamol-Induced Oxidative Stress in Wistar Rats: An In Vivo Evaluation

Abstract

Paracetamol (acetaminophen) is one of the most widely used antipyretic and analgesic agents 
globally. Despite its therapeutic benefits at recommended doses, overdose or prolonged use is 
associated with hepatotoxicity primarily mediated by the formation of the reactive metabolite N
acetyl-p-benzoquinone imine (NAPQI). NAPQI depletes intracellular glutathione (GSH) reserves 
and covalently binds to cellular macromolecules, thereby disrupting membrane integrity, impairing 
mitochondrial function, and promoting oxidative stress. This cascade ultimately compromises 
hepatic structural and functional integrity. The present study investigated the protective 
potential of Bambara nut (Vigna subterranea) extract against paracetamol-induced oxidative 
stress in Wistar rats using an in vivo model. Preliminary phytochemical screening of the Bambara 
nut extract revealed the presence of bioactive constituents including saponins, tannins, flavonoids, 
glycosides, steroids, amino acids, phenolic compounds, and alkaloids—classes of compounds known 
for antioxidant and cytoprotective properties. Twenty adult male Wistar rats were randomly 
assigned into four groups (A–D), with five animals per group. Groups A and B received distilled 
water orally for 14 days, while Groups C and D were administered Bambara nut extract at a dose 
of 100 mg/kg body weight every 12 hours for the same duration. Following an overnight fast, 
oxidative stress was induced in Groups B and D using a single oral dose of paracetamol (3000 mg/kg 
body weight). After 48 hours, animals were sacrificed under mild anesthesia, and blood samples 
were collected for biochemical evaluation of oxidative stress markers using standard analytical 
methods. Results showed that rats administered 3000 mg/kg paracetamol without Bambara nut 
pre-treatment exhibited significant oxidative stress, characterized by elevated activities of 
superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and increased lipid 
peroxidation (LPO) levels. A marked depletion of reduced glutathione (GSH) was also observed, 
indicating compromised antioxidant defense. Conversely, pre-treatment with Bambara nut extract 
attenuated these alterations, suggesting stabilization of antioxidant enzyme activity and 
reduction of lipid peroxidative damage. These findings demonstrate that Vigna subterranea 
possesses significant antioxidant and protective properties against paracetamol-induced oxidative 
stress. Regular dietary inclusion of Bambara nut may therefore confer protective benefits against 
oxidative damage mediated by free radicals.