Safety evaluation of the aqueous extract of Leonotis leonurus shoots in rats.

The aqueous extract from Leonotis leonurus (L) R.Br. (Lamiaceae) shoots was evaluated in female rats for its acute, sub acute, and chronic toxicity together with hematological, biochemical, and histopathological changes. In the acute toxicity test, the extract caused death in animals receiving 3200 mg/kg dose. The extract also caused significant (P < 0.05) changes in red blood cells, packed cell volume, hemoglobin concentration, mean corpuscular volume, platelets, white blood cells and its differentials at doses of 1600 mg/kg in sub-acute toxicity and in as low as 200 mg/kg in chronic toxicity. In biochemical parameters, the extract caused a significant (P < 0.05) decrease in the levels of urea and creatinine at 1600 mg/kg dose and a significant (P < 0.05) reduction in urea, total bilirubin, total protein, albumin, globulin, glutamine transference gamma-glutamyl transferase (GGT), and alanine transminase in the 400 mg/kg dose in chronic toxicity. Changes were also noted in body weights, but no significant changes were observed in the levels of electrolytes (sodium, potassium, and chloride). Clinico-pathologically, starry hair coat, respiratory distress, and mortality were recorded. The extract also caused various histopathological changes in the organs. The study concluded that farmers need to exercise caution in the use of the plant for medicinal purposes.