Toxicity evaluation of the aqueous leaf extract of Gunnera perpensa L. (Gunneraceae)

Abstract

The objective of the study was to determine the potential toxicity of Gunnera perpensa through acute, sub-acute and chronic toxicity tests. For each test, 25 rats distributed in 5 groups of 5 rats per group were used. Group 1, the negative control, were orally administered with distilled water and groups 2 to 5 G. perpensa extract at 50, 100, 200 and 400 mg/kg doses, respectively. Change in behaviour and mortality was recorded. In addition, haematology, serum biochemical assays and histopathology examinations were conducted for sub-acute and chronic tests. Neither rat mortality nor changes in behaviour were noted for acute test. Rat mortality for 400 mg/kg dose of sub-acute and 200 mg/kg of chronic test was 20%. For sub-acute and chronic tests, platelets and monocytes were higher than the reference range, while mean cell volume was low. Creatinine, aspartate transaminase, magnesium, inorganic phosphate and potassium were low in the sub-acute while alkaline phosphatase and inorganic phosphate were low for the chronic test. Mild splenic siderosis and renal inflammation was observed in the sub-acute test. The plant is potentially toxic when used consecutively for a long period.

Key words: Aqueous extract, Gunnera perpensa, haematology, mortality, serum biochemical parameters, toxicity.