Acute and sub-acute toxicity studies of the methanol extract of the leaves of Paullinia pinnata (Linn.) in Wistar albino mice and rats.

BACKGROUND

The aim of this study was to investigate the toxicological effects of the leaves of Paullinia pinnata Linn.(PP) in rodents using Wistar albino mice and rats as experimental models.

METHODS

Acute toxicity study of the methanol extract of PP was carried out in Wistar strain albino mice using varying doses of the extract at 100, 200, 400, 800, 1600, 3200, 6400, and 10,000 mg/kg body weight. These doses were administered orally to male Wistar albino mice with the exception of the control group and observed for morbidity and mortality after Day 1, Day 7 and Day 14. Sub-acute toxicity study was conducted in male Wistar albino rats with varying doses of 50, 100, 200, 400 and 800 mg/kg body weight. These doses were administered orally once daily at 24 hour intervals for 28 days and the vehicle (physiological saline and Tween 80 (70:30 v/v)) was administered to the control groups in the experiments. Biochemical analyses were carried out on the plasma while pathological changes in the kidneys, liver and lungs were examined histologically.

RESULTS

In the acute toxicity study, the mice did not show any form of morbidity or mortality. For the sub acute toxicity study, plasma levels of alkaline phosphatase (ALP), aspartate aminotransferase (AST), total cholesterol and the triglycerides were significantly elevated (p < 0.05) at the 400 mg/kg body weight dosage. Elevated levels of plasma ALP were also observed at 800 mg/kg body weight. The histopathological study showed that the lungs exhibited dose -dependent lymphocytic infiltrations and the pattern of occurrence of lesions observed in the liver was at a frequency of one rat per group at the 400 and 800 mg/kg body weight doses.

CONCLUSIONS

The methanol leaf extract of Paullinia pinnata (Linn.) is well tolerated when orally administered at a dose of 200 mg/kg body weight but toxic at higher doses.