Hexavalent chromium (VI) compounds are widely used in industry, while trivalent chromium (III) is used as a nutritional supplement. CrVI is generally considered more toxic and carcinogenic than its trivalent form and the toxicity of this metal is associated with free radical processes generating reactive oxygen species (ROS). The detailed mechanism of ROS formation by chromium and its compounds remains largely unknown.
This paper investigates the effects of both chromium III and VI on the activity of antioxidant enzymes: superoxide dismutase (SOD), glutathione peroxidase (GPx), the level of reduced glutathione (GSH), and the ferric-reducing ability of plasma (FRAP) in human blood. Our study shows that chromium III does not affect the levels of GSH, but it decreases FRAP. It also affects SOD in a dose-dependent manner while having no effect on the activity of GPx. CrVI, on the other hand, causes a decrease of SOD activity, increases the activity of GPx, reduces the level of GSH and, similarly to CrIII, shows a negative effect on FRAP.