In vivo Toxicological Assessment of the Aqueous Extracts of the Leaves of Carissa edulis (Apocynaceae) in Wistar Rats

Aim: To screen the acute and 28-days subchronic toxicity of the leaves aqueous extract of Carissa edulis (C. edulis).

Design: Experimental and observational study.

Place and Duration: Faculty of health sciences of Cotonou / Institute of Applied Biomedical Sciences of Cotonou, laboratories of Physiology/Human biology/Immunology/ biochemistry and molecular biology( pharmacognosy section) / toxicology and hydrology of Dakar (Senegal) between March 2014 and January 2015.

Methods: The aqueous extract was obtained from the powder of the leaves by a decoction method and evaporation using a rotavapor. In the acute toxicity study (Limit test), a single dose of 2000 mg/kg of the extract was orally administered to three female rats. Different parameters were assessed according to the Organisation for Economic Co-operation and Development (OECD) 423 guidelines for the Testing of Chemicals. During the sub-chronic toxicity, four groups of five rats of either sex received distilled water (control), 31.25,125 and 500 mg/kg of the extract daily for 28 consecutive days by oral gavage. The assay was conducted according to the OECD 407 guidelines.

Results: In both acute and sub-chronic toxicity test, neither mortality nor other toxicity symptoms were observed. This suggests that the median Lethal Dose 50 (LD50) is superior to 2000 mg/kg. There were no significant differences in the body and organ weights between controls and treated animals of both sexes. Indeed, some biological parameters including erythrocytes (6,89±0,07), Haematocrit (41,6±1,69), and Haemoglobin (13,31±0,16) levels were significantly reduced when compared to the control group but this is not imputable pathologically. Histological structures of liver and kidney were normal in both two sexes.

Conclusion: The aqueous extract of C. edulis was found to be safe in acute and 28-days sub-chronic toxicity studies. Furthermore, aspects of the effects of this plant on haematopoiesis, liver and kidney function need to be gained and ascertained over longer periods of toxicity study.