RESUMO
Hunteria umbellata K. Schum (Apocynaceae) is used in herbal medicine for the treatment of diabetes, peptic ulcers, piles, yaws, dysmenorrhea, fevers, infertility, and helminthic infections. The present study investigated the in vivo sub-acute toxicity of the aqueous fruit pulp extract of Hunteria umbellata (H. umbellata). Sub-acute toxicity was evaluated after administering daily oral doses of 200, 400 and 800 mg/kg of H. umbellata extract, for 28 days to the rats. Anthropometric, biochemical, hematological and histopathological parameters were assessed using standard procedures. There were significant reductions (p<0.01) in the pattern of weight gain in 200 and 400 mg/kg H. umbellata -treated rats but no significant differences in the organ weight index between control and treated animals. Hematological and biochemical analysis showed no marked differences in any of the parameters examined in either the control or treated groups but there was significant (p<0.05) thrombocytosis. Pathologically, neither gross abnormalities nor histopathological changes were observed. H. umbellata led to activation of the reticulo endothelial tissue of the spleen as evidenced by proliferation of the sinus histocytes and activation of the lymphoid aggregates in the lungs, indicating activation of the local immune system of the lungs. H. umbellata fruit pulp is relatively nontoxic in animals but there is increased tendency to cause thrombocytosis on prolonged use.