ABSTRACT
Background: The leaves of Hibiscus rosa-sinensis L. (Malvaceae) are used for the treatment of dysentery and diarrhoea, to promote draining of abscesses and as analgesic agent in the traditional medicine of Cook Islands, Haiti, Japan and Mexico. Aim: The present study investigated the oral acute and subacute toxicity of methanol leaf extract of H. rosa-sinensis in mice. Methods: In the acute toxicity study, a single oral dose of 2000 mg/kg of extract was given to five mice at 48 h intervals. Animals were observed individually for any clinical signs of toxicity or mortality for 14 days. In the sub-acute toxicity study, mice were treated with 400 mg/kg and 800 mg/kg doses of extract for 14 days. The haematological and biochemical parameters and histopathology of liver and kidney of animals were studied at the end of experiment. Results: For acute treatment, the extract did not revealed any signs of toxicity or mortality in any animal, during the 14-days observation period. The LD50 of extract was estimated to be greater than 2000 mg/kg. In the sub-acute toxicity study, administration of 400 mg/kg and 800 mg/kg doses of extract to mice for two weeks did not revealed any marked adverse effects on haematological, biochemical parameters and histopathology of liver and kidney in the 400 mg/kg group. But, hepato-renal toxicity as evidenced by elevations of alanine aminotransferase (ALT), aspartate aminotranferase (AST), total and indirect bilirubin, urea and creatinine was seen in the animals that received 800 mg/kg doe of extract for 14 days. In addition, in the same group of animals, the histological assessments of liver and kidney also showed various adverse effects viz. dilated sinusoids, apoptotic nuclei and inflammatory infiltrate inside sinusoidal capillaries in the liver, and marked disorganization of tubules and glomeruli, and enlarged interstitial spaces in the kidney. Conclusion: The results of this study suggest that for traditional medicine purpose only a low dose of H. rosa-sinensis leaf extract (i.e. 400 mg/kg) should be considered as safe.
Key words: Hibiscus rosa-sinensis L, Malvaceae, acute toxicity, subacute toxicity, histopathology
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