SUNSET YELLOW FCF
Sunset yellow FCF was last evaluated by the Joint FAO/WHO Expert
Committee on Food Additives in 1964 (see Annex I, ref. 8).
Since the previous evaluation, additional data have become
When rabbits were fed 0.5 g/kg bw of the colour, the following
metabolites could be identified in 48 hours urine: sunset yellow (2%),
sulfanilic acid (54%), p-acetamido benzene-sulfonic acid (23%),
1-amino-2-naphthol-6-sulfonic acid (55% in 24 hours) (Daniel, 1962).
Rats were given a single oral dose of 100 mg of the colour per
animal. Only 0.8% of the dose administered was found in the faeces.
After a single oral dose of 50 mg only 3.6% was absorbed from
the gastrointestinal tract. The metabolites in the urine were
predominantly products resulting from the reductive fission of the
azolinkage. The liver enzyme that reduces azolinkages plays little
part in metabolism. Reduction of the colour by the intestinal
bacteria is therefore the most probable way to aromatic amines and
aminosulfonic acids; these are then partly absorbed by the intestinal
tract (Radomski & Mellinger, 1962).
Rats were injected the colour intravenously. The bile was
collected for 6 hours and analysed. The average recovery of the colour
was 22% (20-30%) of the administered quantity (Ryan & Wright, 1961).
Fourteen rats were dosed with sunset yellow within the range of
2-25 mg and within 72 hours excreted 0.3 and 1.5% of the administered
dye in urine and bile respectively and 37% of the sulfanilic acid
equivalents in the urine.
In 5 animals dosed with 14C-sunset yellow (2.7 mg, 4.62 µCi)
after 96 hours urinary excretion of radioactivity was 8.5 ± 3.4% of
the dose. The 24 hours urine collection from the sunset yellow rats
contained 40% of the molar equivalents of sulfanilic acid. Intact dye
in the 24 hours urine represented 1-2% of the dose. Peak faecal
excretion occurred during the first 24 hours. The recovery of
radioactivity was 94.5 ± 5.7%. Total recovery of radioactivity was
103 ± 3.3% (Honohan et al., 1977).
Special studies on cell cultures
Sunset yellow FCF did not induce cell transformation using the
F 1706 Fisher rat embryo fibroblasts even after 10 subcultures, i.e.
no typical morphological alterations were noted and the cells were not
significantly tumorigenic (Price et al., 1978).
Special studies on multigeneration reproduction
Doses of sunset yellow FCF were administered in the diet, and
were based on multiples (1x, 10x, 30x, and 100x) of the ADI or of the
projected safe dose determined from data of previous long-term
feeding studies in rats and dogs. However, no doses in excess of
1000 mg/kg/day were used. The human usage level of the colour was also
a factor in determining the levels used in the diet. Data through the
F2b litter gave no indication of adverse effects on reproductive
performance (Pierce et al. 1973 - available in summary only).
Special studies on mutagenicity
The colour was tested for mutagenic activity in a concentration
of 0.5 g/100 ml in cultures of Escherichia coli. No mutagenic effect
was found (Luck & Rickerl, 1960).
Sunset yellow FCF was not mutagenic in Salmonella typhimurium
strains TA 1538, TA 98 or TA 100, with or without metabolic
activitation. Various sulfonated naphthylamines were also without
mutagenic activity (e.g. 1-amino-2-naphthol-4-sulfonic acid) (Garner &
Sunset yellow did not produce reverse mutations in 4 strains
(TA 1535, TA 1538, TA 98, TA 100) of Salmonella typhimurium when
tested in presence and absence of liver microsomal (S9) fractions
obtained from rats pretreated with phenobarbitone (Viola & Nosotti,
Sunset yellow FCF did not cause any increase in mitotic gene
conversion in diploid yeast B2 34 (S. cerevisiae) (Sankaranarayanan
& Murthy, 1979).
Sunset yellow was studied for its ability to cause DNA-damage in
an E. coli rec assay. Reverse mutations were studied in E. coli WP
2 uvrA and S. typhimurium TA 1538 in fluctuation assays. Both types
of assays were conducted with and without metabolic activation. Sunset
yellow FCF did not demonstrate genotoxicity (Haveland-Smith & Combes,
Special studies on teratogenicity
Sunset yellow FCF was administered to rats by gavage at dose
levels of 100, 300 and 1000 mg/kg/day on days 6 through 15 of
gestation. The mean weight of offspring of the dams which received 300
and 1000 mg/kg/day were decreased, but the effect was of doubtful
significance. No effect was observed on any other maternal (body
weight, corpora lutea, empty implantation sites, early resorptions,
late resorptions, and live or dead term foetuses) or foetal (sex,
external, internal and skeletal abnormalities) parameters evaluated.
No terata were observed in the offspring of these dams (International
Research and Development Corporation, 1972a).
Sunset yellow FCF was administered to rabbits by gavage at
dosage levels of 100, 300 and 1000 mg/kg/day on days 6 through 18 of
gestation. No effect was observed on any maternal (body weight,
corpora lutea, early and late resorptions, and live or dead term
foetuses) or foetal (mean body weight, sex, external and skeletal
abnormalities) parameters evaluated. An incomplete twin which was not
considered compound related occurred at the 1000 mg/kg/day level
(International Research and Development Corporation, 1972b).
Animal Route (mg/kg bw) Reference
Mouse Oral >6 000 Gaunt et al., 1967
i.p. 5 000 Gaunt et al., 1967
Rat Oral >2 000 Lu & Lavallée, 1967
Oral >10 000 Gaunt et al., 1967
i.p. 3 800 Gaunt et al., 1967
Groups of 10 immature female rats were given the colour
subcutaneously twice daily for 3 days. The rats were killed on the
fourth day. The colour was administered in aqueous solution at a level
of 250 mg/kg bw each injection. No oestrogenic activity (uterine
weight) was detected (Graham & Allmark, 1969).
Twenty rats were given subcutaneously 1 ml of a 1% solution of
the colour twice a week for 7 months. Totally 55 injections were
given. Only 1 intraperitoneal tumour was found (the observation period
was not mentioned) (Deut. Forsch., 1957).
The colour was given to a group of 16 rats as a 2% solution in
the drinking-water for 10 months. The diet of these rats was
suboptimal in vitamin B2. In comparison with a group without the
colour, it was noticed that the colour accelerated the growth of the
young rats and improved the survival rate of these animals. No
histopathological changes in the liver were observed (Manchon & Lowy,
Feeding of sunset yellow FCF to groups of 15 male and 15 female
rats at dietary levels of 0 (control), 0.5, 1.0, 2.0 or 3.0% for 90
days evoked no adverse effect on growth or food consumption but there
was slight diarrhoea throughout the study at 3% and during the first
few weeks at 2%. There was no departure from normality in the
haematological investigations or in the terminal liver and kidney
function tests. At autopsy, the caecum was enlarged at the 2 and 3%
levels and the testes at the 3% level. There were no histological
changes attributable to sunset yellow FCF (Gaunt et al., 1967).
In experiments with guinea-pigs it was found that this colour had
no sensitization activity (Bär & Griepentrog, 1960).
Sunset yellow FCF was fed to groups of 3 male and 3 female pigs
at levels of 0 (control), 250, 500 and 1000 mg/kg/day for 98 days. No
differences were detected between test and control animals in weight
gain, haematological indices, composition of urine, organ weights or
serum levels of transaminases and urea. No abnormalities were seen at
autopsy or on microscopical examination of the tissues (Gaunt, 1969).
A group of 30 mice were given 0.05% of the colour in their
drinking-water for 52 weeks. The animals were kept for their lifespan.
The weekly ingestion of the colour was about 17 mg and totally 884
mg/mouse. Nine lymphomas and one benign intestinal tumour were found
in 7 survivors. In the controls, 5 lymphomas and one intestinal tumour
were found in 13 survivors. There were 60 mice in the control groups
at the beginning of the experiment (Bonser et al., 1956).
Two-year feeding studies were conducted with this colour using 2
strains of mice; C57 black and C3H at levels of 1 and 2%. One
hundred animals of each strain were fed the colour at both dosage
levels and 200 animals of each strain were fed a control diet. There
was no effect on tumour formation (FDA, 1964).
Groups of 30 male and 30 female mice were given diets containing
0.2, 0.4, 0.8 or 1.6% sunset yellow FCF for 80 weeks. A group of 60
male and 60 female mice served as controls. The feeding of sunset
yellow FCF did not adversely affect the death rate within the groups,
the rate of body weight gain, the organ weights or the haematological
findings. The incidence and severity of the histopathological findings
were similar in treated and control mice and there was no evidence of
an increased incidence of tumours in the mice given sunset yellow FCF
In 11 Graffi or Lakeview (LVG) suckling hamsters, sunset yellow
FCF (1.0 mg) injected either subcutaneously or intraperitoneally did
not increase mortality and no tumours were detected over a 330-day
period (Price et al., 1978).
Five male and 5 female rats were given the colour at a level of
4% in the diet for periods up to 18 months. There was some staining of
the glandular stomach and small intestine and in some animals granular
deposits were observed in these organs. No tumours were observed
(Willheim & Ivy, 1953).
Four groups of 15 male and 15 female rats were given diets with
0, 0.03, 0.3 and 1.5% of the colour for 64 weeks. The mortality of the
rats was as in the control group. No influence on food intake, growth,
organ weights, histopathology and blood picture was found. No
significant difference in tumour incidence was found (Mannell, 1958).
Groups of 24 litter-mated Osborne-Mendel rats, evenly divided by
sex, were fed the colour at 0, 0.5, 1.0, 2.0 and 5.0%. There was a
statistically insignificant increase in the number of mammary tumours.
The number of tumours that were found in the different groups were
respectively 2, 1, 6, 3 and 6.
Additional feeding studies were conducted with Osborne-Mendel and
Sprague-Dawley rats; 100 animals of each strain were fed at 1.0 and
2.0%, and 200 of each strain were placed on the control level. Gross
and microscopic pathology showed no effect on tumour formation (FDA,
Four groups of 20 rats, both sexes, were used. Dietary levels of
2.0, 1.0, 0.5, and 0.0% were fed. At the 79th and 102nd weeks, the
survivors were sacrificed and autopsied. Slight but non-significant
growth retardation occurred in female rats. Food consumption and
survival were not affected. Histopathologically, in the liver there
were only the usual changes found in older animals. No neoplastic
change was seen in the rats and no carcinogenicity was detected
Feeding studies with dogs were conducted; 4 beagles were fed the
colour at each level of 1.0 and 5.0%. Two of the 4 animals at 5% and 1
animal at 1.0% lost weight progressively and had to be sacrificed
after 2-3 months. In general, 5.0% in the diet of dogs was moderately,
and 1.0% was slightly, toxic. Weight loss and diarrhoea were the chief
clinical effects. Gross and microscopic pathological changes were
present but were not characteristic.
Five female beagle dogs were fed the colour at 2.0% in the diet
for 7 years. No histopathology was reported (FDA, 1964).
OBSERVATIONS IN MAN
A skin test with the colour showed in patients sensitive to
p-phenyl-enediamine eczematous hypersensitivity produced by cross-
sensitization. This reaction is explained by the ease of its
transformation into compounds of quinone structure and upon the
ability of the quinone compound to couple with certain body
constituents (Baer et al., 1948).
Several long-term studies have been carried out in rats. Long-
term studies have also been carried out in mice, hamsters, and dogs.
The biochemical studies indicate that in the rat this colour is
reduced at the azo linkage by bacteria present in the intestine and
that some of the breakdown products are absorbed and excreted in the
urine. The Committee reconsidered earlier studies on this compound
together with newer studies and decided to allocate a revised ADI.
Levels causing no toxicological effect
Rat: 1% in the diet, equivalent to 500 mg/kg bw.
Dog: 2% in the diet, equivalent to 500 mg/kg bw.
Estimate of acceptable daily intake for man
0-2.5 mg/kg bw.
Baer, R. L., Leider, M. & Mayer, R. L. (1948) Possible eczematous
cross-hypersensitivity between p-phenylenediamine and azodyes
certified for use in foods, drugs and cosmetics, Proc. Soc.
exp. Biol. (N.Y.), 67, 489-494
Bär, F. & Griepentrog, F. (1960) Die Allergenwirkung von Fremden
Stoffen in den Lebensmitteln, Med. u. Ernahr., 1, 99-104
Bonser, G. M., Clayson, D. B. & Jull, J. W. (1956) The induction
of tumours of the subcutaneous tissues, liver and intestine in
the mouse by certain dyestuffs and their intermediates, Brit.
J. Cancer, 10, 653
Daniel, J. W. (1962) The excretion and metabolism of edible colours,
Toxicol. appl. Pharmacol., 4, 572-594
Deutsche Forschungsgemeinschaft, Bad Godesberg, Federal Republic of
Germany, Farbstoff Kommission (1957) Mitteilung 6
EEC (1982) Report of the Scientific Committee for Food on the
sensitivity of individuals to food components and food additives.
In: Commission of the European Communities, Food Science and
Technology, EUR 7823
FDA (1964) Summary of toxicity data on colours: FD and C Yellow No. 6.
Unpublished report from the U.S. Food and Drug Administration
Garner, R. C. & Nutman, C. A. (1977) Testing of some azodyes and their
reproduction products for mutagenicity using S. typhimurium
TA 1538, Mutation Res., 44, 9-19
Gaunt, I. F. et al. (1967) Acute (rat and mouse) toxicity studies on
sunset yellow FCF, Fd Cosmet. Toxicol., 5, 747-754
Gaunt, I. F. et al. (1969) Short-term toxicity study on sunset yellow
FCF in the miniature pig, Fd Cosmet. Toxicol., 7, 9-16
Gaunt, I. F. et al. (1974) Long-term toxicity of sunset yellow FCF
in mice, Fd Cosmet. Toxicol., 12, 1-10
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for genotoxic activity, Fd Cosmet. Toxicol., 18, 215-221
Honohan, T. et al. (1977) Intestinal absorption of polymeric
derivatives of the food dyes sunset yellow and tartrazine in
rats, Xenobiotica, 7, 765-774
International Research and Development Corporation (1972a) FD & C
yellow No. 6. Teratology study in rats. Unpublished report
submitted to the Inter-Industry Colour Committee, No. 306-004
International Research and Development Corporation (1972b) FD & C
yellow No. 6. Teratology study in rabbits. Unpublished report
submitted to the Inter-Industry Colour Committee, No. 306-003
Kanisawa, H. et al., Chiba-Daigakn Fuhai Kenkynsho Kokokn (1967) 20,
101-110. Chronic oral toxicity of sunset yellow FCF, Chem.
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colours used in drugs and foods, Cand. pharm. J., 97, 30
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VI - Report, Z. Lebensmitt.-Untersuch., 112, 157
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soleil sur la croissance du rat, Fd Cosmet. Toxicol., 2,
Mannell, W. A., Grice, H. C., Lu, F. C. & Allmark, M. G. (1958)
Chronic toxicity studies on food colours. Part IV - Observations
on the toxicity of tartrazine, amaranth and sunset yellow in
rats. J. Pharm. Pharmacol., 10, 625
Pierce, E. C. et al. (1974) Multigeneration reproduction studies with
certified colours in rats. Inter-Industry Colour Committee Task
Force, Cosmetic Toiletry and Fragrance Association, Inc.,
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carcinogenicity and toxicity of food dyes, Int. J. Cancer,
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excretion in rats of the water-soluble azodyes FD & C Red No. 2,
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rat bile, J. Pharm. Pharmacol., 13, 492
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permitted food colours for the induction of gene conversion in
diploid yeast, Mutation Res., 67, 309-314
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submitted to WHO, April 1964
Viola, M. & Nosotti, A. (1978) Application of the Ames test on some
dyes, Boll. Chim. Farm., 117, 402
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