Biological activity and subchronic toxicity study of Allanblackia floribunda Oliv. on experimental rats

Allanblackia floribunda Oliv. (Elephant rice) belongs to the family Clusiaceae. It is confined to tropical Africa where it is used traditionally for the treatment of malaria, asthma and inflammatory diseases. This study evaluated the biological activity of methanol extract of A. floribunda's stem bark and leaf in addition to the seed oil as well as the subchronic toxicity of the stem bark extract. Standards procedures were used to screen the biological activity of A. floribunda. The subchronic toxicity profile was investigated by administering orally 100, 300 and 600 mg/kg b. wt of the stem bark extract to male Albino rats for 28 days consecutively. After the treatment period, changes in the various biochemical parameters and alteration in the expression of antioxidants, cytokine, Kidney injury molecule-1 (KIM-1) and albumin genes of the sensitive organs were used to assess the safety level of the stem bark extract. The stem bark extract had more phytochemicals and better antioxidant activities compared with the leaf extract and oil. Administration of the stem bark extract did not result in treatment related changes in markers for hepatic and renal injury (aspartate transaminase, alanine transaminase, total protein, albumin, globulin, creatinine and urea). The extract resulted in an increase in hepatic malondialdehyde. Also, hepatic and renal glutathione levels increased significantly. The blood composition was normal and the genes coding for albumin in the liver together with catalase in the liver and kidney were up-regulated. Tumor necrosis factor – alpha (TNFα) gene expression was down-regulated in the liver and up-regulated in the kidney while KIM-1 gene was down-regulated in the treated animals compared with the control. This study confirmed that A. floribunda's stem bark extract is richer in bioactive compounds than the leaf extract and seed oil. Furthermore, it is relatively safe to animals when used in moderate dose.