Oral Acute and Sub-chronic Toxicity Assessment of Methanol and Aqueous Extracts of the Stem Bark of Bridelia exaltata (Scrub Ironbark) in Wistar Rats

This study aimed to evaluate the oral acute and sub-chronic toxicity of methanol and aqueous extracts of the stem bark of Bridelia exaltata (Scrub Ironbark), a medicinal plant widely used in Africa. A total of 65 wistar rats were used for this analysis. Acute toxicity was assessed in Wistar rats (n = 30) given a single oral dose of 2000mg/kg, 4000mg/kg and 6,000 mg/kg extracts and monitored for 14 days, while sub-chronic toxicity was evaluated in a separate group (n = 35) administered daily oral doses of 200, 400, and 600mg/kg extracts for 90 days. Endpoints included clinical signs, phytochemical composition, hematological and biochemical parameters, and histopathological examination of vital organs. Data were analyzed using one-way ANOVA with p < 0.05 considered significant. Phytochemical analysis revealed high flavonoid (533.83 ± 22.89 mg/g) and phenol (251.40 ± 10.60 mg/g) contents. In the acute study, no mortality or behavioral changes occurred, indicating an LD₅₀ > 6,000 mg/kg. In the sub-chronic study, high-dose methanol and aqueous extracts caused significant (p < 0.05) reductions in red blood cell count, hemoglobin concentration, and packed cell volume, while biochemical parameters (ALT, AST, creatinine, urea) showed no significant differences (p > 0.05) compared to controls. Histopathology revealed no renal abnormalities but mild dose-dependent changes in the heart, liver, and brain at the highest doses. These findings indicate that B. exaltata stem bark extracts are relatively safe at low to moderate doses but may produce hematological and organ alterations at high, prolonged exposures. It is recommended that traditional and supplemental use be limited in dosage and duration to minimize potential risks.