Subchronic Administration of Ethanolic Leaf Extracts of Rauwolfia vomitoria and Gongronema latifolium Impairs Spatial Memory and Induces Cerebellar Cytoarchitectural Alterations in Adult Wistar Rats

Abstract

Aims: The use of medicinal plants in sub-Saharan Africa raises concerns regarding neurological safety. This study evaluated the effects of sub-chronic oral administration of ethanolic leaf extracts of Rauwolfia vomitoria (RV) and Gongronema latifolium (GL), singly and in combination, on spatial learning and memory, organosomatic indices, and cerebellar cytoarchitecture in adult Wistar rats. Study Design: Twenty adult male Wistar rats (200 ± 10 g) were assigned to four groups (n = 5): control (distilled water, 5 mL kg−1), RV (150 mg kg−1), GL (200 mg kg−1), and RV + GL (150 + 200 mg kg−1). Place and Duration of Study: The study was conducted at the University of Uyo and Akwa Ibom State University, Nigeria, between June and July 2025. Methodology: Extracts were administered orally for seven consecutive days. Spatial learning and memory were assessed before and after treatment using the Morris water maze. Terminal body weight and brain, liver, and kidney weights were recorded, and organosomatic indices were calculated. Cerebellar tissue was processed for haematoxylin and eosin staining. Data were analysed using one-way ANOVA followed by Tukey's post-hoc test. Results: Treated groups showed significantly prolonged escape latencies after administration (p < 0.05). Organosomatic indices were reduced compared with controls (p < 0.05). Cerebellar sections showed Purkinje cell hypertrophy, pyknotic nuclei, karyorrhexis, and reduced granular cell density, with the most marked changes in the combined-treatment group. Conclusion: Sub-chronic administration of the extracts, particularly in combination, was associated with impaired spatial performance and cerebellar cytoarchitectural alterations in adult Wistar rats.