Neurobehavioral and Biochemical Effects of Caffeine and Vernonia amygdalina Leaf Extract in Healthy Male Wistar Rats

Abstract

Caffeine is a non-selective antagonist of adenosine A1 and A2A receptors, whereas Vernonia amygdalina contains phytochemicals with reported antioxidant and anti-inflammatory properties. Although both agents have been examined separately, information on their comparative and combined effects on neurobehavioural and biochemical outcomes in healthy animals remains limited. This study investigated the neurobehavioural, biochemical and histopathological effects of caffeine and hydromethanolic Vernonia amygdalina leaf extract (HEVA) in healthy male Wistar rats. Thirty-five rats (80–100 g) were randomly assigned to seven groups (n = 5): control, HEVA (150 mg/kg), HEVA (300 mg/kg), caffeine (2.5 mg/kg), caffeine (5 mg/kg), HEVA (150 mg/kg) + caffeine (2.5 mg/kg), and HEVA (300 mg/kg) + caffeine (5 mg/kg). Treatments were administered orally once daily for 21 days. Neurobehavioural performance, oxidative stress biomarkers and neurochemical markers were assessed. The combination treatment produced the most consistent improvements in cognitive and motor performance. HEVA increased SOD, CAT, GPx and GSH levels and reduced MDA, indicating improved antioxidant defence and reduced lipid peroxidation. HEVA and combination-treated groups also showed lower AChE activity and higher BDNF concentrations than controls (p < 0.05), suggesting improved cholinergic neurotransmission and neuronal plasticity. Overall, moderate caffeine administration and HEVA, particularly in combination, demonstrated neurofunctional and antioxidant effects in healthy male Wistar rats.