Histopathological and Biochemical Effects of Sub-Chronic Administration of Aqueous and Methanolic Extracts of Loranthus MicraNTHUS

Abstract

The histopathological and biochemical effects of sub-chronic administration of high doses of aqueous and methanolic extracts of Loranthus micranthus (African mistletoe) leaves parasitic on Parkia biglobosa were studied in male albino Wistar rats. Acute toxicity studies were performed according to Lorke´s method. High doses of both extracts (1000 and 2000 mg/kg) were administered daily via the intraperitoneal route to four groups of rats (n = 5) respectively for 30 days. The fifth group of rats (n = 5) similarly received 5 ml/kg each of normal saline (negative control). Blood samples were collected from the rats at the end of the experiment by retrorbital puncture for analysis of relevant biochemical parameters using assay kits. The liver, kidney and heart of the rats were also harvested for histopathological examination. The results of the acute toxicity studies indicated that both extracts are practically safe since the intraperitoneal LD50 were greater than 5000 mg/kg in mice. Creatine kinase levels were significantly reduced in the treated groups suggesting the stabilization of cardiac musculature by these extracts. Histological results also revealed mild portal lymphocytic infiltration, mild to moderate portal inflammation and expansion with numerous pyknotic nuclei in the liver of rats treated with the aqueous extract. Both extracts induced cholestatic liver injury in rats. Varying degrees of moderate histopathological findings in the kidney of the treated rats were also seen. Even though extracts of L. micranthus leaves have been shown to be practically safe under acute administration in rats, caution should be exercised when mistletoes are administered for the treatment of life-long diseases such as diabetes and hypertension.

Keywords: Sub-chronic toxicity, Loranthus micranthus, histopathology

Nigerian Journal of Pharmaceutical Research, Vol. 9 No 2 pp. 78 - 85 (September 2011)