Synthetic dyes have been reported to exert detrimental effects on the health of humans. This study evaluated the effects of a diet containing tartrazine (Tz) on rats which included: i) biochemical parameters including hepatic enzymes, kidney functions and profiles of lipids; ii) markers of oxidative stress in cells by measuring concentrations of malondialdehyde (MDA) and glutathione (GSH); iii) activities of selected, key hepatic antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx); iv) pathologies of liver. Also, protective effects of three doses of curcumin (CUR), a natural food coloring agent, on these parameters in rats that had been co-exposed to Tz.
Materials and methods:
Fifty Wistar male albino rats were randomly divided into five groups: Group I, control, where rats were fed a normal diet; Group II, rats were fed normal diets containing 7.5 mg Tz/kg diet, dry mass (dm); In Groups III, IV and V, rats were fed diets containing Tz plus 1.0, 2.0 or 4.0 g CUR/kg diet, dm, respectively. Whole blood was collected after 90 d of exposure, homogenates of liver were prepared and the above analyses were conducted.
Exposure to Tz in the diet caused statistically significant (p<0.05) greater concentrations of lipids, hepatic enzymes, and kidney function parameters as well as the indicator of oxidative stress MDA. Alternatively, activities of several antioxidant enzymes (i.e. CAT, SOD and GPx) and concentration of the substrate GSH, an indicator of non-enzymatic antioxidant capability, were significantly (p<0.05) less than those in control rats not exposed to Tz. Tz caused various histopathological changes in livers of rats, which were characterized by hemorrhage and dilatation of the central vein and sinusoids, hepatocyte necrosis, intracellular vacuolization. Co-administration of 2.0 (Group IV) or 4.0 g CUR/kg diet (Group V) with Tz significantly mitigated effects on functions of liver and kidney and the profile of relative concentrations of lipids. CUR significantly (p<0.05), and almost completely, reversed effects on enzymatic and non-enzymatic antioxidant and indicators of oxidative stress about rats fed Tz (Group II) to values in control rats. However, co-administration of 1.0 g CUR with Tz (Group III) exhibited a negligible effect on those parameters. The results of this study suggest benefits of the use of CUR, as a promising natural food additive to counteract oxidative stress caused by dietary exposure to the synthetic dye Tz due to potent protective antioxidant activity.
Blending some natural food additives, such as CUR with diets containing synthetic dyes, could moderate potential effects of these artificial dyes. Decreasing or removing toxins in food is an essential step for the amelioration of human health status and decreasing risk of onset or progression of degenerative diseases.