In Vivo Acute and Subchronic Toxicity of Stereospermum acuminatissimum Stem Bark Aqueous Extract.

Abstract

Background: Despite its traditional use in Africa for weight management, the safety profile of the aqueous stem bark extract of Stereospermum acuminatissimum remains undocumented. This study evaluated its acute and subchronic toxicity in Wistar rats.

Methods: Acute toxicity was assessed according to OECD Guideline 425 using a single oral dose of 5000 mg/kg. Subchronic toxicity was evaluated over 56 days at doses of 150, 300 and 600 mg/kg/day. Satellite groups (the control and the 600 mg/kg/day group) were maintained for an additional 14 days to observe the reversibility of any treatment-related effects. Parameters studied included body/organ weights, haematological, biochemical, lipid and histopathological profiles.

Results: No mortalities or signs of acute toxicity were observed during the 14 days following extract administration. Subchronic administration did not affect survival or relative organ weights, although the 600 mg/kg dose induced minor structural alterations in affected organs. The extract significantly reduced body weight gain. At 150 mg/kg, the extract sex-specifically improved lipid profiles by lowering triglycerides in males and increasing HDL cholesterol in females. Haematological assessment revealed a dose-dependent increase in platelet counts in male rats at 600 mg/kg, which returned to baseline levels after the 14-day recovery period. Elevated AST and ALT fully reversed in females post-recovery; however, elevated ALT persisted at 600 mg/kg in males. Creatinine remained stable or decreased, and minor variations in urea concentrations in both sexes returned to baseline during recovery.

Conclusion: S. acuminatissimum aqueous extract reduces body weight gain and improves lipid profiles at low-to-moderate doses (150-300 mg/kg), providing its traditional use. However, the persistence of elevated ALT levels and focal leucocyte infiltration in males at 600 mg/kg indicates high-dose hepatotoxicity, highlighting a narrow therapeutic window and the need for careful liver function monitoring during prolonged exposure.