Acute Toxicity of Aqueous and Ethanolic Extracts of Strophanthus hispidus Stem Bark

The aim of this study was to determine the median lethal dose (LD50) of the extracts (aqueous and ethanol) of S. hispidus stem bark. A modified Lorke’s (1983) method was used in this study. Varying doses of the extracts were administered orally to male albino rats. Treatment-related signs of toxicity and mortality were monitored for 24 hrs and continued for 72 hrs. Treatment-related mortality was observed at the dose of 1000 mg/kg body weight and above in the ethanolic extract and 1600 mg/kg body weight in the aqueous extract. Signs of sedation, exophthalmos, decreased locomotion and appetite in the aqueous or ethanolic treated animals were observed in the early stages of experimentation. However, these signs were not sustained in surviving animals. The LD50 was 2154 and 2039 mg/kg body weight for aqueous and ethanolic extracts of S. hispidus stem bark respectively. The results showed that 1000 mg/kg body weight and above of S. hispidus stem bark may be slightly toxic. Therefore, moderate dosage is advised for purposes of medication.