Sub-acute toxicity of the chloroformic extract of Rapanea melanophloeos (L.) Mez in rats

Abstract

Ethnopharmacological relevance Cape beech (Rapanea melanophloeos) is an important medicinal plant that is widely used in most of Africa. Currently, little toxicological information is available on its safety following prolonged use. Aim of the study In this study, we sought to evaluate the oral sub-acute toxicity of Rapanea melanophloeos stem bark chloroformic extract using Sprague Dawley rats. Materials and methods Six-week old rats were orally administered with the extract at dosage levels of 100 mg/kg, 300 mg/kg and 1000 mg/kg for 28 days. Clinical signs, hematological and clinical chemistry parameters were monitored, while organ weights and organ pathology were evaluated at the end of the study. Results The extract caused a significant reduction in bodyweight at 1000 mg/kg. The hematological profiles of animals at this dose showed an increase in the erythrocyte count and the hematocrit that were accompanied by decrease in the mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. Biochemical parameters were not altered in a dose-related manner when compared to the controls. There were time associated alterations on both hematological and biochemical parameters, but pathological examination did not reveal any treatment related changes in any of the organs. Conclusion Our results demonstrate that the chloroformic stem bark extract of Rapanea melanophloeos may be of no toxicological concern at dosage levels up to 1000 mg/kg. Rapanea melanophloeos can therefore be used confidently in African traditional medicine at these or lower dosage levels.