Antioxidant Properties of Carica papaya on Cadmium Toxicity on Prefrontal-Cortex of Adult Wistar Rats

Background: Cadmium is a carcinogenic agent in humans, and therefore, a cancer causing substance. In the body it is extensively circulated, but it is bound mainly to erythrocytes. Though cadmium binds to various macromolecules and proteins in the body, it is not well metabolized. Cadmium intensifies oxidative damage in the nervous system (and various other organ systems) thereby causing harm. The damage results from an increase in production of reactive oxygen species and inhibition of antioxidant enzymes as shown by previous researches. This study investigated possible effects of Carica papaya as an antioxidant in the damage of the brain caused by cadmium.

Methods: Thirty Wistar rats weighing between 120 g-180 g of both sexes were divided into six groups of five animals each and used in this study. Six groups were induced intraperitoneally with a single dose of 3.5 mg/kg body weight of cadmium sulphate. Two out of these six groups were treated with high and low doses of Carica papaya, 250 mg/kg and 400mg/kg body weight respectively for the period of four weeks. After sacrifice, enzyme assays were carried out on the tissue supernatant homogenates.

Results: The investigation showed that MDA level of activities decreased in the prefrontal cortex supernatant of groups 1, 2 and 6 animals and an increase in the MDA level of activities were observed in groups 4 and 5 rats which was significant at p<0.05. There was a decrease in catalase activities in groups 2 and 3 rats, also, an increase in CAT activities in groups 4 and 5 rats, the decrease was significant in groups 2 and 3 animals as compared with the control group 1 rats. GST activities decreased in groups 2, 3, 4, 5 and 6 rats and the decreased activities were significant at p<0.05 when compared with control group 1 animals. Progressive increase in the superoxide dismutase was observed in groups 1, 2, 3, 4, 5 and 6 rats and this increase in activities was found significant at p<0.05 in groups 4, 5 and 6 rats when compared with the control group 1 rats.

Conclusion: The present study has justified the ameliorative properties of Carica papaya in scavenging the free oxygen radicals and supplement the cellular antioxidant systems.