INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY

    WORLD HEALTH ORGANIZATION



    TOXICOLOGICAL EVALUATION OF SOME
    FOOD COLOURS, ENZYMES, FLAVOUR
    ENHANCERS, THICKENING AGENTS, AND
    CERTAIN FOOD ADDITIVES



    WHO FOOD ADDITIVES SERIES 6







    The evaluations contained in this publication were prepared by the
    Joint FAO/WHO Expert Committee on Food Additives which met in Rome,
    4-13 June 19741


    World Health Organization     Geneva     1975






              

    1  Eighteenth Report of the Joint FAO/WHO Expert Committee on
    Food Additives, Wld Hlth Org. techn. Rep. Ser., 1974, No. 557.
    FAO Nutrition Meetings Report Series, 1974, No. 54.

    YELLOW 2G

    BIOLOGICAL DATA

    BIOCHEMICAL ASPECTS

         Injection of 1 mg/kg bw i.v. into adult rats as an aqueous
    solution resulted in 96% excretion in the bile (Ryan & Wright, 1961).
    It has been suggested that the biliary excretion rate is related to
    the relative protein-binding properties of the dye in liver and blood
    (Priestly & O'Reilly, 1966). It is possible that Yellow 2G is
    metabolized in a similar manner to tartrazine which has a structure
    related to Yellow 2G (Gaunt et al., 1970; Walker, 1970; Westöö, 1965).
    Incubation of Yellow 2G with a buffered bacterial suspension from rat
    intestine for four hours at 37° under oxygen-free nitrogen resulted in
    38% azo-reduction of the colour (Roxon et al., 1967).

    TOXICOLOGICAL STUDIES

    Acute toxicity

         No information available.

    Short-term studies

    Rat

         Yellow 2G was fed to four groups of 15 male and 15 female rats at
    dietary levels of 0, 100, 1000 or 10 000 ppm for 13 weeks. The
    colourant was decolourized in the caecum yielding a colourless product
    which turned red on exposure to the air. No adverse effects were seen
    in the rate of body weight gain, or in the results of haematological
    examinations, serum chemistry, renal cell excretion and concentration
    tests. No gross or micropathological effects were detected which could
    be attributed to the colourant. There were isolated changes of the
    weights of kidney, small intestine, adrenal glands and testes in rats
    receiving 1000 or 10 000 ppm Yellow 2G but these were not considered
    to be related to treatment. The caeca were enlarged in rats fed a diet
    containing 10 000 ppm (Gaunt et al., 1970).

    Pig

         Four groups of three pigs of each sex were given Yellow 2G in
    doses of 0 (control), 5, 50 or 500 mg/kg/day for 15 weeks. The faeces
    of the pigs at the two higher dose levels developed a reddish colour
    on exposure to the air, probably due to oxidation of a metabolite of
    the colouring. There was an initial diarrhoea lasting one or two days

    in half the pigs at the highest dose level. No adverse effects were
    seen in the rate of body weight gain, haematology, examination of
    urine, organ weights or histopathological examination (Gaunt et al.,
    1974).

    Long-term studies

    Mouse

         Groups of 48 male and 48 female mice (TF1 strain) were given 0
    (control), 30, 300 or 1500 ppm Yellow 2G in the diet for 80 weeks. No
    adverse effects were seen on the growth, appearance, or the behaviour
    of the animals during the study. Histopathological examination in
    progress (Gaunt et al., 1974).

    Rat

         Groups of 48 male and 48 female rats (Wistar strain) were given
    diets containing 0 (control), 100, 1000 or 10 000 ppm of Yellow 2G for
    two years. No adverse effects were seen on the growth, appearance, or
    the behaviour of the animals during the study. Histopathological
    examination in progress (Gaunt et al., 1974).

    Comments:

         The short-term studies in the rat and pig did not reveal any
    serious adverse toxicity. Two long-term studies in the mouse and rat
    have been done but the results have not yet been reported. Multi-
    generation, embryotoxicity including teratology studies are not
    available but have been reported in progress. The metabolism has not
    been examined to a satisfactory extent.

    EVALUATION

         Not possible on the data available.

    REFERENCES

    BIBRA (1971) Private communication

    Gaunt, I. F. et al. (1971) Fd. Cosmet. Toxicol., 9, 343

    Gaunt, I. F. et al. (1974) Fd. Cosmet. Toxicol. (In press)

    Priestly, B. G. & O'Reilly, W. J. (1966) J. Pharm. Pharmacol., 18, 41

    Roxon, J. J., Ryan, A. J. & Wright, S. E. (1967) Fd. Cosmet. Toxicol.,
         5, 367

    Ryan, A. J. & Wright, S. E. (1961) J. Pharm. Pharmacol., 13, 492

    Westöö, G. (1965) Acta. Chem. Scand., 19, 1309

    Walker, R. (1970) Fd. Cosmet. Toxicol., 8, 659

    See Also:
       Toxicological Abbreviations
       Yellow 2G (WHO Food Additives Series 12)
       YELLOW 2G (JECFA Evaluation)