ABSTRACT
Acute and sub-chronic toxicity studies of the aqueous extract of the root bark of C. sieberiana (Caesalpiniaceae), a plant used locally in Ghana for the treatment of pain, was carried out in rodents. In the acute study, a single oral dose (5000 mg/kg) of the aqueous extract of C. sieberiana (NPK) was administered to six rats and six mice, and observed for 14 days for signs of acute toxicity. In the sub-chronic study, rats were administered with NPK (15- 750 mg/kg) daily for three months. Urinalysis, haematological and biochemical analyses were carried out on urine, blood and serum samples collected at the end of the three-month treatment. Histological analyses of the liver, heart, kidney and lung tissues were also done. The results showed that administration of 5000 mg/kg of NPK to animals did not result in death. There were no significant differences (p>0.05) between control and test animals in the haematological assay. The albumin, alkaline phosphatase and total bilirubin were higher (p<0.05) in test animals compared to the controls. Liver micrographs showed centrilobular necrosis at the dose of 750 mg/kg. The findings, therefore, show that the oral toxicity of NPK in rodents is low (oral LD50 > 5000 mg/kg). However, the extract may have deleterious effects on the liver at high doses on prolonged administration.