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Acute In-Vivo Histological Effect Of Food Colourants On Some Rat Tissues

FP Ching
JO Akpan
MD Ekpo
JA Ekanem


The purpose of the investigation was to determine the acute in-vivo toxic effect of two commonly used food colourants in Southern Nigeria namely Egg Yellow and Bright Red on selected rat tissues using histopathologic changes to determine toxicological effect. The colourants are found in many local markets in Nigeria and have been claimed to be harmless by the manufacturers. The parameters studied were effect of route of administration, dose-response effect, and organ based toxicity. Egg Yellow and Bright Red colourants were administered to wistar albino rat either orally or by intraperitoneal injection. The doses given orally were 500mg, 1000mg and 2000mg per kg body weight whilst the injected dosages included 100mg, 250mg, 500mg, 1000mg and 2000mg per kg body weight. The colourants were dissolved in distilled water and were administered at a constant volume of 5mls daily for three days. Control rats were given similar treatment with equivalent volume of distilled water only. The rats were sacrificed and tissues, namely liver, kidney, spleen, stomach and ileum excised for gross pathological examination.

Gross examination of tissues revealed marked ulcerative lesions and haemorrhage on the antra of stomach of rats given the colourants at 2000mg per kg orally. Gross examination also revealed mild splenomegaly, hepatomegaly and enlarged pale kidneys in the rats administered the colourants at 1000mg or 2000mg per kg either by oral or intraperitoneal routes.

Histopathological examination of sections from liver, kidney, spleen, stomach and ileum of rats treated with the colourants revealed a variety of dose-related degenerative, inflammatory and proliferative lesions which included necrosis, especially in the liver, Ulcerative lesions were found in the stomach. In the kidneys, glomeruli and renal papillae necrosis were observed. Also observed were splenic tissue necrosis. No discernible lesions were observed in the stomach and ileum after intraperitoneal route injection. Tissues from the control rats showed normal morphology which was remarkably different from those of the treated rats. No Observable Effect Level (NOEL) for intraperitoneal injection of Egg Yellow were 100mg and 250mg. Bright Red colourant produced histomorphological changes at all the dosages tested indicating a lower toxicity index than Egg Yellow. It is concluded that the colourants are not pharmacological inert and are capable of causing in-vivo organ dysfunction. They should be used cautiously in food preparations.

KEY WORDS: Food Colourants, Egg Yellow, Bright Red, Histopathological Effect.

Global Journal of Pure and Applied Sciences Vol.11(2) 2005: 241-247