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.
CALCIUM AND SODIUM-5'-RIBONUCLEOTIDES
BIOLOGICAL DATA
BIOCHEMICAL ASPECTS
The biochemistry of the constituent nucleotides has already been
discussed and their relationship to purine biosynthesis and uric acid
and allantoin formation in mammals is clear (Kojima, 1973).
Mice given i.v. 500 mg/kg DSRN showed initial behavioural
depression followed by excitation, no muscular relaxation, depressed
rotating activity, did not have modified electroshock convulsions,
decreased dose-dependency (200 and 500 mg/kg i.v.) the convulsive dose
of metrazol. Doses of 50, 125 and 500 mg/kg i.v. all prolonged loss of
righting reflex (Kojima, 1973). 10, 25 and 50 mg/kg DSRN i.v. in cats
produced transient dose dependent hypotension and increased blood flow
to hind limb. 10 mg/kg intra-arterially increased transiently blood
flow to hind limbs without affecting ECG. Concentrations up to
10-5 g/ml had no effect on isolated guinea-pig atrium, 10-4g/ml
showed positive ino- and chronotropic effects. 100 mg/kg s.c. had no
effect on intestinal transport in mice as shown by charcoal
transportation. Concentrations below 10-4g/ml had no effect on
isolated guinea-pig ileum regarding response to acetyl chlorine,
histamineor barium chloride 100 mg/kg s.c. in rats had no effect on
gastric juice secretion, pH or total acidity. 100 mg/kg s.c. in mice
depressed salivary secretion. 100 mg/kg orally had no diuretic effects
in rats. 500 mg/kg orally did not affect the analgesic response of
mice and carrageenin oedema in rats (Kojima, 1973). Mice given i.v.
500 mg/kg disodium 5'-ribonucleotide showed initial behavioural
depression followed by excitation, no muscular relaxation, depressed
rotating activity, did not have modified electroshock convulsions,
decreased dose-dependency (200 and 500 mg/kg i.v.) the convulsive dose
of metrazol. Doses of 50, 125 and 500 mg/kg i.v. all prolonged loss
of righting reflex (Kojima, 1974). 10, 25 and 50 mg/kg disodium
5'-ribonucleotide i.v. in cats produced transient dose dependent
hypotension and increased blood flow to hind limb. 10 mg/kg
intra-arterially increased transiently blood flow to hind limbs
without affecting ECG. Concentrations up to 10 mg/l had no effect on
isolated guinea-pig atrium, 100 mg/l showed positive ino- and
chronotropic effects. 100 mg/kg s.c. had no effect on intestinal
transport in mice as shown by charcoal transportation. Concentrations
below 0.1 g/l had no effect on isolated guinea-pig ileum regarding
response to acetyl choline, histamine or barium chloride. 100 mg/kg
s.c. in rats had no effect on gastric juice secretion, pH or total
acidity. 100 mg/kg s.c. in mice depressed salivary secretion,
100 mg/kg orally had no diuretic effects in rats. 500 mg/kg orally did
not affect the analgesic response of mice and carrageenan oedema in
rats (Kojima, 1973). Three healthy volunteers (males) were given low
purine diets containing 250-4 000 mg disodium 5'-ribonucleotide daily.
The higher level raised the serum uric acid level and urinary uric
acid output but the 2 g level did not raise serum uric acid level
above the accepted normal range. No adverse effects were reported
(Cooper et al., 1972).
TOXICOLOGICAL STUDIES
Special studies on reproduction
Rat
Four groups of 10 male and 20 females were given 0, 0.1%, 1% and
2% DSRN daily in their diet over three generations. No adverse effects
have been noted in parent animals as regards mortality, mating
performances, body weight change, food consumption, pregnancy rate,
duration of gestation and at autopsy. Litter parameters as assessed by
loss, size, pup weights, pup mortality and incidence of abnormalities
were unaffected by any dose level. Organ weights and skeletal staining
and histology of F3 pups on 2% showed no evidence of treatment
related effects (Palmer et al., 1971).
Special studies on teratogenicity
Mouse
One group of 14 pregnant mice received daily 2 g/kg bw DSRN
during the 8-13th day of pregnancy. No significant effects on the
fetuses were noted (Kaziwara et al., 1971).
Rat
One group of 9 pregnant rats received daily 2 g/kg bw DSRN during
days 9-15 of pregnancy. No significant effects on the fetuses were
noted (Kaziwara et al., 1971).
Monkey
Two pregnant cynomolgus monkeys received daily 500 mg/kg bw DSRN
and another three pregnant animals received daily 1000 mg/kg DSRN
during days 21-31 of pregnancy. No significant effects were noted on
fetuses (Kaziwara et al., 1971).
Acute toxicity
LD50
Animal Route mg/kg bw Reference
Mouse Oral and 10 000 Usui et al., 1971
Rat parenteral
Short-term studies
Rat
Five groups of 10 male rats were given 0, 0.2%, 0.4%, 0.8% and 2%
disodium 5'-ribonucleotide in their diet daily for six months. No
significant abnormalities were seen regarding behaviour, body weight
gain, food intake, haematology, urinalysis, macroscopic and
histological findings (Usui et al., 1971).
Dog
Three groups of one male and one female beagle were given 2%, 5%
and 10% of disodium 5'-ribonucleotide in their diet for 4-6 weeks
without adverse effects (Noel et al., 1970).
Long-term studies
Rat
Three groups of 10 male and 10 female rats each received 0, 1%
and 2% DSRN in their diet daily for 24 months. No significant
abnormalities were noted regarding behaviour, body weight gain, food
intake, haematology, urinalysis, macroscopic and histological findings
(Usui et al., 1971).
Dog
Four groups of four male and four female beagles received 0,
0.1%, 1% and 2% DSRN in their diet daily for two years. No dog died
nor were any significant abnormalities noted as regards body weight
gain, haematology, clinical biochemistry, ophthalmoscopy and
urinalysis. Terminal macroscopy, histology or organ weight studies
showed no adverse effects (Rivett et al., 1971).
OBSERVATIONS IN MAN
Three healthy volunteers (males) were given low purine diets
containing 250-4000 mg DSRN daily. The higher level raised the serum
uric acid level and urinary uric acid output but the 2 g level did not
raise serum uric acid level above the accepted range. No adverse
effects were reported (Kojima, 1973).
Comments:
Inosinates, guanylates and ribonucleotides are substances
normally present in all tissues and their role in purine metabolism as
well as their breakdown in the majority of mammals, but not man, to
uric acid and allantoin is well known. The various products have been
studied adequately in long-term, reproduction and teratology tests.
Ingestion of large amounts of these compounds by man can increase the
serum uric acid level and urinary uric acid excretion and this needs
to be considered in relation to people with gouty diathesis and those
taking uric-acid retaining diuretics. Hence specific mention of the
addition of these substances on the label may be indicated. The
changes in dietary purine intake from the use of flavour enhancers are
no greater than those likely to be occasioned by changes in
consumption of those dietary items, which are the main contributors of
purine.
EVALUATION
Acceptable daily intake not specified1
REFERENCES
Cooper, A. J. et al. (1972) Huntingdon Research Centre, Unpublished
report
Kaziwara, K., Mizutani, M. & Ihara, T. (1971) J. Takeda Res. Lab., 30
(2), 314
Kojima, K. (1973) Toxicology, 2, (In press)
1 The statement "ADI not specified" means that, on the basis of the
available data (toxicological, biochemical, and other), the total
daily intake of the substance, arising from its use or uses at the
levels necessary to achieve the desired effect and from its acceptable
background in food, does not, in the opinion of the Committee,
represent a hazard to health. For this reason, and for the reasons
stated in individual evaluations, the establishment of an acceptable
daily intake (ADI) in mg/kg bw is not deemed necessary.
Noel et al. (1970) Personal Communication from HRC
Palmer, A. K., Lovel, M. R. & Spicer, E. J. F. (1971) Report No.
4554/71/710 by HRC to Takeda
Rivett, K. F. et al. (1971) Report No. 4500/71/656 by HRC to Takeda
Usui, T. et al. (1970) Personal communication from HRC