Acute and Sub-chronic Toxicity of Aqueous Extract of Roots of Khaya senegalensis (Desr.) A. Juss. in Mice and Rats Respectively

Aim: Khaya senegalensis is one of the key medicinal plants used discretionarily in traditional medicine as remedies to several health conditions. This study aimed to establish the safety of Khaya senegalensis root aqueous extract in experimental animals with the purpose of optimizing its therapeutic value.

Methodology: A total of 74 animals (20 rats and 54 mice) were randomly assigned into two main groups based on toxicity plan; acute and sub-chronic toxicity. Mice were divided into 9 groups (6 per group) for the acute toxicity study while rats were divided into 4 groups (5 per group) for sub-chronic toxicity assessment.

Results: The acute concentrations of the extract in mice induced dose-dependent clinical signs severities such as: twitching, increase rate of respiration, sedation, abdominal muscle contractions and increased motor activity. The lethal dose 50 value of the extract was estimated as 320mg/ kg body. The sub-chronic concentrated grades in the rats especially the higher doses elicited significantly increased serum liver enzymes values when compared to the control, while at low dose the values were comparable to that of the control. Also observed were the evidences of renal cellular pathology ranging from mild to severe tubular cell degeneration, tubular cell depletion and congestion of the renal cortex. The liver pathologies such as hepatic portal congestion, cytoplasmic vacuolations and nuclear degeneration were strikingly visible mostly at the higher doses. The lymphocyte and platelet counts were the only haematological parameters that increased significantly more particularly at low dose when compared with the control.

Conclusion: This study has shown that Khaya senegalensis seems to be safe only at low doses. However, caution should be taking in its administration for therapeutic purposes especially when long-term usage is desired.