Immunological studies on Amaranth, Sunset Yellow and Curcumin as food colouring agents in albino rats

The use of food dyes is at least controversial because they are only of essential role. Moreover many of them have been related to health problems mainly in children that are considered a very vulnerable group. This study was carried out to investigate the effect of oral administration of Amaranth, Sunset Yellow and Curcumin for 4 weeks at doses of 47, 315 and 157.5 mg/kg b. wt. and after 2 weeks all animals were immunostimulated by intra peritoneal injection of sheep RBCs 10% (1 ml/rat). Body weight, relative body weight, total and differential leukocytes count, mononuclear cell count, delayed hypersensitivity, total protein and serum fractions were determined. Results revealed that oral administration of Amaranth, Sunset Yellow and Curcumin did not affect the body weight gain or the spleen weight. On the other hand Sunset Yellow and Curcumin significantly decreased the weight of thymus gland of the rats. Total leukocyte count were not affected while Amaranth and Curcumin-treated rats revealed a significant decrease in neutrophiles and monocytes and a compensatory increase in lymphocytes. Moreover, oral administration of Sunset Yellow revealed a significant decrease in monocyte percent. Amaranth, Sunset Yellow and Curcumin significantly decreased the delayed hyper sensitivity. Total serum protein, albumin, total globulin and albumin/globulin (A/G) ratio were not affected by administration of the colouring agents. Oral administration of Amaranth increases the density of albumin band. On the other hand oral administration of Curcumin decreases the density of the albumin band. Oral administration of any of the tested colouring agents did not change the density of globulin region as compared to control group. In conclusion we found that both synthetic (Amaranth and Sunset Yellow) and natural (Curcumin) colouring agents used at doses up to 10 times the acceptable daily intake exerted a depressing effect on the cellular but not humoral immune response.