RESUMO
The toxicity profile of the aqueous methanolic extract of Berlina grandiflora (BG) stem bark was studied in rats. The rats were administered graded doses (125-500 mg/kg p.o) of the extract daily for 21 days and the effects on body weight, organ weight, clinical signs, gross pathology, hematology, histology and serum biochemical parameters were measured. The relative weights of the heart, liver, kidneys and lungs of treated rats were unaffected but there were significant changes in the relative weights of the spleen and testes. The packed cell volume and hemoglobin concentrations were slightly reduced whereas total leucocytes counts were increased remarkably. Alkaline phosphatase and Creatine Kinase levels were reduced in all the groups but Glutamate oxaloacetate was significantly elevated. Total proteins and albumin levels remained normal. BG elicited a significant increase in gamma glutamyl transferase concentrations at 250 mg/kg. No significant changes occurred in urea, uric acid and BUN concentrations but calcium levels shot up remarkably. Histological findings did not reveal any treatment-related effects. The acute toxicity LD50 was estimated to be >2000 mg/kg but dose-related mortality rates of 16.7, 33.4 and 50% were observed during the sub-acute toxicity studies. These findings have once more highlighted the limitations of acute toxicity LD50 testing and suggest that BG may exert varied toxicological effects when administered orally in rats.
