ETHYL VANILLIN
1. EXPLANATION
Ethyl vanillin was evaluated at the eleventh meeting of the
Committee (Annex 1, ref 14) when an Acceptable Daily Intake of 0-10
mg/kg bw was allocated to this compound. The eleventh meeting noted
that few metabolic studies had been carried out on this compound and
considered that further metabolic studies were desirable.
Ethyl vanillin was placed on the agenda of the present meeting on
the basis of partial application of the method for setting priorities
for the safety review of food flavouring ingredients (Annex 1,
reference 83).
Since the last review, additional data have become available and
are summarized and discussed in the following monograph. The
previously published monograph has been expanded and is incorporated
into this monograph.
2. BIOLOGICAL DATA
2.1 Biochemical aspects
2.1.1 Metabolism and Pharmacokinetics
This compound is probably metabolized to glucuroethyl vanillin
and ethyl vanillic acid, of which some is conjugated with glucuronic
and sulfuric acids (Williams, 1959).
2.2 Toxicological studies
2.2.1 Acute toxicity
Species Route LD50 Reference
(mg/kg bw)
Mouse i.p. 750 Caujolle & Meynier, 1954a
Rat oral 1590 Sporn, 1960
oral >2000 Jenner et al., 1964
s.c. 1800 Deichmann & Kitzmuller, 1940
Guinea pig i.p. 1140 Caujolle & Meynier, 1954b
Dog i.v. 760 Caujolle et al., 1953
* Maximum non-lethal dose, 450 mg/kg bw; LD50 = 950 mg/kg bw.
A dose of 150 mg/kg bw caused no adverse effects and at 2500
mg/kg bw only a transient increase in respiration rate was observed
when groups of 6 rabbits were given ethyl vanillin by oral gavage.
The minimum oral lethal dose was reported to be 3000 mg/kg bw
(Deichmann & Kitzmuller, 1940).
2.2.2 Short-term studies
2.2.2.1 Rats
Doses of 300 mg/kg bw were administered to rats by gavage twice
weekly for 14 weeks without any adverse effects. In another
experiment, groups of 16 rats were fed 20 mg/kg bw daily for 18 weeks
without adverse effect but 64 mg/kg bw daily for 10 weeks reduced
growth rate and caused myocardial, renal, hepatic, lung, spleen and
stomach injuries (Deichmann & Kitzmuller, 1940).
Groups of male rats were fed 0, 2 or 5% ethyl vanillin in the
diet for one year without any adverse effects (Hagan et al., 1967).
Sixteen rats were given 30 mg ethyl vanillin weekly for 7 weeks
without adverse effect on growth, food intake or protein utilization
(Sporn, 1960).
2.2.2.2 Rabbits
Single rabbits were given ethyl vanillin orally in 10% aqueous
glycerine at doses of 15 mg/kg bw/day for 13 of 15 days, or 26 of 31
days, 32 mg/kg bw/day for 15 of 17 days, 41 mg/kg bw/day for 26 of 31
days or 49 mg/kg bw/day for 43 of 49 days. At the highest dose level,
anaemia, diarrhoea and lack of weight gain were observed but no toxic
signs were reported at any of the lower levels (Deichmann &
Kitzmuller, 1940).
2.2.3 Long-term/carcinogenicity studies
2.2.3.1 Mice
The maximum tolerated dose for ethyl vanillin in mice when
administered i.p. 3 times per week for 2 weeks and tolerated through
a subsequent 24 week observation period was reported to be 75 mg/kg
bw. Administration of ethyl vanillin i.p. at doses of 15 or 75 mg/kg
bw three times a week for eight weeks resulted in respective
mortalities of 8/20 and 10/20 animals. Control animals receiving i.p.
injections of the vehicle, tricaprylin, had survival rates of 77/80
(males) and 77/80 (females). In the control group, 28% of males and
23% of females developed lung tumours whereas in the treated groups
only one animal, in the higher dose group, exhibited a single lung
nodule. It was concluded that ethyl vanillin did not potentiate the
pulmonary tumour responses in strain A mice (Stoner et al., 1973).
2.2.3.2 Rats
Groups of 12 male and 12 female rats were fed diets containing 0,
0.5, 1 and 2% ethyl vanillin for 2 years or 2% and 5% for one year
without any adverse effects on growth, organ weights of major organs,
hematology and histology of major tissues (Hagan et al., 1967).
2.2.4 Reproduction studies
No data available.
2.2.5 Special studies on mutagenicity
Ethyl vanillin was negative in a mouse micronucleus assay when
given to groups of four mice as two i.p. doses of up to 1 g/kg bw at
an interval of 24 hours (Wild et al., 1983).
Ethyl vanillin did not induce mutations in the Ames Salmonella/
microsome assay against Salmonella typhimurium strains TA92, TA1535,
TA100, TA1537, TA94 and TA98, with or without metabolic activation
using rat or hamster liver S9 fractions (Wild et al., 1983;
Mortelmans et al., 1986).
In in vitro assays using Chinese hamster ovary cells, ethyl
vanillin did not induce chromosomal aberrations; the compound did
cause an increase in polyploid cells but the significance of this is
unclear and similar polyploidy was induced by riboflavin (Ishidate
et al., 1984).
Ethyl vanillin did not induce sister chromatid exchanges in
cultured Chinese hamster ovary cells in vitro but was reported to
enhance the ability of mitomycin C to cause sister chromatid exchanges
(Sasaki et al., 1987).
No heritable mutations were detected when ethyl vanillin was used
in the BASC on Drosophila melanogaster (Wild et al., 1983).
In a study on the anti-mutagenic potential of flavourings, ethyl
vanillin was reported to show marked anti-mutagenic activity against
mutagenicity induced by 4-nitroquinoline-1-oxide, furylfuramide,
captan or methylglyoxal in Escherichia coli WP2s but was ineffective
against mutations induced by Trp-P-2 or IQ in Salmonella typhimurium
TA98. It was assumed that the anti-mutagenic activity was due to
enhancement of an error-free recombinational repair system (Ohta
et al., 1986).
2.3 Observations in man
In a 24-hour closed patch test in 25 subjects, ethyl vanillin
tested at 2% in petrolatum produced a mild irritation. No
sensitization reactions were evoked when ethyl vanillin was used at 2%
in petrolatum in a maximization test on 25 volunteers (Kligman, 1970).
3. COMMENTS
The Committee noted that none of the previously evaluated long-
term or carcinogenicity studies meet modern standards in that fewer
animals per group had been used than would be the present norm.
Accordingly the Committee reduced the previous ADI and made it
temporary.
4. EVALUATION
Level causing no toxicological effect
Rat: 5000 ppm, equivalent to 250 mg/kg bw/day.
Estimate of temporary acceptable daily intake
0-5 mg/kg bw.
Further work required by 1992
1. An adequate short-term study in rats, and
2. metabolic studies in rats.
5. REFERENCES
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CAUJOLLE, F. & MEYNIER, D. (1954b). The comparative toxicities of
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CAUJOLLE, F., MEYNIER, D. & MOSCARELLA, C. (1953). The comparative
toxicity of ethyl vanillin and 4-hydroxy-5-ethoxyisophthalic
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