Toxicity Studies of the Extracts of Parkia biglobosa Stem Bark in Rats

Extracts of Parkia biglobosa stem bark is used in Nigerian traditional medicine (NTM) to treat malaria, diarrhea and pains. To establish the toxicity profile of the medicine such parameters as the lethal dose (LD50) as well as effects on body functions and organs were evaluated in albino Wistar rats. The bioactive constituents of the water and methanol extracts were also evaluated as a link to toxicity. The LD50 was greater than 5000mg/kg per oral (p.o) for both extracts.  No significant (P< 0.05) changes in body weights and vital organs of treated animals. However, at 5000mg/kg of water extract, a significant  increase  in  relative  weight  of  the  kidneys  and  hyper -cholesterolemic  effects  were observed. The extract also elicited significant increase in blood glucose level. The kidneys and livers of animals treated with P. biglobosa water extract for 14 days revealed histopathological evidence of pathological lesions. The methanol extract did not show any changes in the levels of hepatic and hematological  parameters, histopathological evidence of  pathological lesions, and  serum level of urea, uric acid, bilirubin,  creatinine and total protein concentrations. Treatment elicited hypo -cholesterolemic effects and significant reduction in blood glucose level occurred in all the groups. The phytochemical screening revealed the presence of tannins, flavonoids, saponins, terpenes, cardiac glycosides, phenols  and reducing  sugars  in the  methanol extract,  the water  extract  showed the presence of similar constituents with the absence of flavonoids and cardiac glycosides. This study has shown the toxicity characteristics of the methanol and water extracts of the stem bark P. biglobosa in short time treatment with the extracts. This study has shown the diversity in toxicity as well as the chemical constituent of the stem barks of P. biglobosa in relation to the extraction solvent. However this study provides the basis for further study on the detailed toxic and pharmacological effects of the extracts of P. biglobosa stem bark and their active component(s).

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