Renal histopathological effects of Afzelia africana n-Hexane seed oil extract following sub-chronic oral exposure in Wistar rats

Abstract

Background: Afzelia Africana, commonly known as African Mahogany, is widely utilised across sub-Saharan Africa for nutritional and ethnomedicinal purposes. While the seed might be safe in traditional dietary amounts, the development of therapeutic concentrated lipophilic extracts introduces new toxicological variables. The renal system’s high metabolic demand for processing concentrated lipids necessitates a rigorous safety evaluation. This study evaluated the renal histopathological effects of repeated oral administration of an n-hexane extract of A. africana seed oil in Wistar rats.

Methods: Twenty adult male Wistar rats were randomly assigned into four groups (n = 5 per group): control and three treatment groups receiving 1000, 1250, and 1500 mg/kg body weight of the extract daily for 28 days. Renal toxicity was assessed using body weight measurements and a semi-quantitative histopathological scoring system applied to hematoxylin and eosin-stained kidney sections.

Results: Final body weights were significantly reduced in rats treated with 1000 mg/kg and 1250 mg/kg compared with controls (p < 0.05), while rats receiving 1500 mg/kg showed no significant difference. Histological examination revealed mild tubular fatty change and interstitial inflammation at 1000 mg/kg, preserved renal architecture at 1250 mg/kg, and early nephrotoxic changes including tubular degeneration, vascular congestion, and inflammatory infiltration at 1500 mg/kg. The observed pattern suggests a non-monotonic dose–response relationship.

Conclusion: Sub-chronic exposure to A. africana n-hexane seed oil extract induces dose-dependent renal histopathological changes with a non-monotonic profile. While 1250 mg/kg appeared to be a tolerable dose under the conditions of this study, early nephrotoxic alterations were evident at 1500 mg/kg. These findings indicate a narrow renal safety margin for lipophilic extracts of A. africana and underscore the need for caution in the use of non-polar solvent-derived botanical preparations.