Acute toxicity and phytochemical screening of stem bark extracts of Entandrophragma angolense (Welw.) C.DC. (Meliaceae)

Abstract

The plants are a rich source of drugs because they produce a variety of bioactive molecules, most of which probably act as chemical defence against predators or pathogens. The present study was conducted to determine the phytochemical constituents and the acute toxicity of aqueous extracts, ethanolic and methanolic of stem bark from Entandrophragma angolense in rats. The acute toxicity studies were carried out on the basis of the guidelines of the OECD 423. The aqueous extracts, ethanolic and methanolic were administered orally at a single dose of 300, 2000 and 5000 mg / kg body weight to the rats. The extracts showed lesser toxicity at dose of 2000 mg / kg body weight; however at 5000 mg/kg body weight dose the mortality rate was 2/3. Thus, the Lethal Dose 50(DL50) is in the range of 2000 to 5000 mg / kg body weight. These results suggest that the aqueous extracts, ethanolic and methanolic of stem bark of E. angolense could be used with some degree of safety by oral route. Phytochemical analysis of aqueous extracts, ethanolic and methanolic of stem bark of E. angolense revealed the presence of alkaloids, saponins, tannins, flavonoids, terpenoids, quinones, cardiac glycosides, leucoanthocyanins, phenols and steroids. These extracts contain important bioactive compounds, which justifies the use of this plant in traditional medicine for the treatment of various diseases.