Oral acute and sub-chronic toxicity assessment of aqueous leaf extract of Simarouba glauca DC (Paradise tree)

Abstract

<i>Simarouba glauca</i> has been widely reported to be effective against a number of diseases and possesses medicinal benefits. Thus, the study was conducted to evaluate the toxic effect of aqueous leaf extract of <i>Simarouba glauca</i> (AESG) on relevant organs of male <i>Wistar</i> rats. The oral acute toxicity of AESG was evaluated according to the method described by Lorke. Sub-chronic toxicity of AESG was carried out in line with the guidelines of the Organization for Economic Co-operation and Development (OECD), using a total of twenty-four (24) male <i>Wistar</i> rats divided into four groups of six rats each. Test rats were orally administered AESG at doses of 500, 1000 and 2000 mg /kg body weight, respectively, daily for thirty (30) days. At the end of the study, rats were fasted overnight and sacrificed; the relevant biochemical and histopathology evaluation was carried out. Statistical analysis was conducted using the GraphPad Prism®, version 7. The data obtained indicated that the <i>LD₅₀</i> exceeded 5000 mg/kg. There were significant increases (<i>P < 0.05</i>) in percentage (%) body weight of test rats. There were no significant differences (<i>P < 0.05</i>) in mean liver, kidney, and heart weight/body weight (IOW/BWT) ratios. The AST activity was significantly lowered (<i>P < 0.05</i>) in rats administered AESG 2000 mg/kg. The ALP activities were significantly elevated (<i>P < 0.05</i>), while the GGT activities were significantly lowered (<i>P < 0.05</i>) in all groups of rats administered AESG. Plasma conjugated and unconjugated bilirubin were significantly lowered and elevated (<i>P < 0.05</i>), respectively in rats administered AESG 1000 and 2000 mg/kg. Plasma urea was significantly elevated (<i>P < 0.05</i>) in rats given AESG 1000 mg/kg. Test rats given AESG 2000 mg/kg recorded significant reduction (<i>P < 0.05</i>) in plasma sodium ions concentration. Rats given AESG 500 mg/kg recorded significant reduction (<i>P < 0.05</i>) in plasma bicarbonate ion levels. The findings suggest that AESG was not significantly toxic to the liver, kidney, and heart.