Assessment of oxidative stress status and select heavy metal levels in serum of rats fed cooked phosphide powder residuecontamined cowpea

Abstract

Ayobola A. Iyanda, Oliatan A. Adeomi

Although it is widely believed that the mechanistic mode of action of the toxic effects of phosphide is inhibition of cytochrome c oxidase enzyme, the involvement of oxidative stress has also been reported when animals were exposed to its post-fumigation residue. The aim of this study is to determine whether prior food processing (cooking) of phosphide residue contaminated cowpea will affect its ability to induce oxidative stress or not. Eighteen Wistar rats were divided into 3 groups of 6 rats each. The twelve rats in groups 1 and 2 were fed with cooked phosphide residue contaminated and uncontaminated cowpea, respectively, while the rats in group 3 were fed cooked untreated cowpea and served as control. Activities or serum levels of indices of oxidative stress as well as serum levels select heavy metals were determined. Results of the study revealed that while reduced glutathione and reduced/oxidized glutathione ratio were significantly reduced compared with control; malondialdehyde, catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase and glutathione S transferase were not significantly changed. Moreover, none of the heavy metals (Al, Cd, Si, As, Pb) were significantly changed compared with control. The results of the study suggest that when phosphide residue contaminated cowpea was cooked before being fed to Wistar rats its oxidative stress potential was altered.