Toxicity and anti-trypanosomal effects of ethanolic extract of Butyrospermum paradoxum (Sapotaceae) stem bark in rats infected with Trypanosoma brucei and Trypanosoma congolense

The ethanolic extract of Butyrospermum paradoxum stem bark, commonly used in the traditional treatment of various diseases including animal and human trypanosomosis in north-eastern Nigeria, was tested for toxicity and anti-trypanosomal efficacy in rats infected with Trypanosoma congolense and Trypanosoma brucei. Following intra-peritoneal administration, the extract induced behavioural changes, morbidity and mortality in the rats. The symptoms observed included anorexia, dehydration, depression, prostration, coma and death. These symptoms were noted at high doses (>800 mg/kg) only. At necropsy, the pathological lesions were mainly congestion and oedema of the lungs, bronchi, bronchioles and the kidney, hepatomegally and focal necrosis of the liver cells. The severity of the symptoms and lesions were dose related. The intra-peritoneal LD50 of the extract was 820 mg/kg. The extract produced anti-trypanosomal effect through the complete suppression or delay in parasite establishment with reduction in the level of parasitaemia and the severity of the attendant disease as well as enhanced survival of the rats infected with Trypanosoma congolense and Trypanosoma brucei. The results suggest that the folkloric medicinal application of the extracts of Butyrospermum paradoxum has a pharmacological basis.