Acute and Sub-chronic Toxicity Assessment of Methanol Leaf Extract of Persea americana (avocado) in Wistar Rats

Abstract

Persea americana (Avocado) leaves are widely used in traditional medicine, yet scientific data on their toxicological safety remains limited. This study evaluated the acute and sub-chronic toxicity profiles of the methanolic leaf extract of P. americana in Wistar rats. Acute toxicity was assessed using 28 rats (7 groups; n = 4 per group) administered single oral doses ranging from 500–5000 mg/kg. Sub-chronic toxicity involved 24 rats (4 groups; n = 6 per group) treated daily with doses of 400–1600 mg/kg for 28 days. Cardiovascular, haematological, biochemical, and histopathological parameters were measured. Data was statistically analysed using one-way analysis of variance (ANOVA), followed by Duncan’s Multiple Range Test (DMRT) for post hoc comparisons, with significance set at p<0.05. The estimated median lethal dose (LD₅₀) was 3162.27 mg/kg, with signs of toxicity observed at 4000 mg/kg and 50% mortality at 5000 mg/kg. No significant changes in blood pressure were detected across dose groups. Sub-chronic administration resulted in dose-dependent alterations in weight gain and mild reductions in PCV, Hb, and RBC counts at the highest dose. Histopathological analysis revealed progressive cardiac, hepatic, and renal damage with increasing dosage, despite largely unaltered serum biochemical markers. These findings suggest that P. americana methanol leaf extract is relatively safe at lower doses but may pose organ-specific risks at higher concentrations and prolonged exposure. Further research is warranted to elucidate underlying mechanisms, particularly oxidative stress, and to guide the development of safe and standardized therapeutic applications.