Toxicopathological evaluation of a 28-day repeated dose administration of Zea mays L. (Poaceae), Stigma maydis aqueous extract on key metabolic markers of Wistar rats

Abstract

Zea mays L., Stigma maydis is a waste product of corn cultivation with good therapeutic applications against several debilitating diseases. This study evaluated the safety of its aqueous extract on key metabolic markers of Wistar rats using Organisation for Economic Co-operation and Development (OECD) guidelines. In the acute toxicity test, single oral administration of 5000 mg/kg body weight of the extract was given to the animals and observation was made for 14 days. The repeated dose toxicity study was conducted via daily oral administration of graded concentrations (50, 100, 200 and 500 mg/kg) of the extract for 28 days. Clinical toxicity signs, behavioural changes, haematological, and biochemical parameters were thereafter evaluated. The extract at 5000 mg/kg produced no treatment-induced signs of toxicity, behavioural changes or mortality in the animals. Thus, its LD50 was estimated to be above 5000 mg/kg. In the repeated dose toxicity study, treatments with the extract revealed no significant difference in haematological and clinical biochemistry parameters. However, at 500 mg/kg, the extract significantly increased the body weight, the exploratory ability as well as serum concentrations of leukocytes and platelets of the treated animals compared to the control group. Cage side observations recorded no treatment-mediated signs of toxicity and macro-histopathological examinations of all the investigated organs also revealed no obvious morphological alterations. Overall, the effects elicited by the aqueous extract of Z. mays, S. maydis suggest that it is unlikely to be toxic to the investigated tissues and may be labelled and classified as practically non-toxic within the tested doses and period of investigation.