Effects of sub-chronic oral administration of hydromethanolic stem extract of Costus afer Ker Gawl. (Costaceae) on body weight, relative organ weight (ROW) and histopathology of selected organs in rats

Abstract

Adverse effects of plant extracts on body weight, relative organ weight and histopathology are important indicators of toxicity. The aim of this study was to evaluate the acute and sub-chronic toxicity of the hydromethanolic stem extract of Costus afer Ker Gawl. (Costaceae). OECD (2008) Guideline 425 was used to evaluate oral acute toxicity of the extract. Sub-chronic oral administration of the extract on body weight, relative organ weight (ROW) and histopathology of selected organs in Wistar rats were evaluated using  OECD 1995 guideline 407. Forty Wistar rats of both sexes were divided into 4 groups. Rats in control group (Group I) received 1 ml/kg/day distilled water while Groups II, III and IV rats received 250, 500, and 1000 mg/kg/day of the extract  respectively for 28 days. All treatments were administered orally. The rats were sacrificed under light halothane anaesthesia on the 29^th day and the target organs were harvested, weighed and examined macroscopically for any morphological changes and microscopically for any lesions. There were no significant changes  in mean body weights of rats and relative organ weights of selected organs in the extract treated groups when compared with the control group (distilled water). Although histological features of the brain, heart, stomach mucosa, lungs, spleen, ovaries and uterus in the extract treated groups were similar to those of control, slight to moderate renal and hepatic necrosis and necrosis of secondary spermatogenic cells at doses of 500 mg/kg and above of the extract were observed in the kidneys, liver and testes respectively. Caution should be exercised on sub-chronic administration of this extract as it may be toxic to the kidneys, liver and testes.