Toxicological evaluation of some food
additives including anticaking agents,
antimicrobials, antioxidants, emulsifiers
and thickening agents
WHO FOOD ADDITIVES SERIES NO. 5
The evaluations contained in this publication
were prepared by the Joint FAO/WHO Expert
Committee on Food Additives which met in Geneva,
25 June - 4 July 19731
World Health Organization
Geneva
1974
1 Seventeenth Report of the Joint FAO/WHO Expert Committee on
Food Additives, Wld Hlth Org. techn. Rep. Ser., 1974, No. 539;
FAO Nutrition Meetings Report Series, 1974, No. 53.
TRAGACANTH GUM
Explanation
This substance has been evaluated for acceptable daily intake by
the Joint FAO/WHO Expert Committee on Food Additives (see Annex 1,
Ref. No. 19) in 1969.
Since the previous evaluation, additional data have become
available and are summarized and discussed in the following monograph.
The previously published monograph has been expanded and is reproduced
in its entirety below.
BIOLOGICAL DATA
BIOCHEMICAL ASPECTS
In a comparative study of the hypocholesterolemic activity of
various mucilaginous polysaccharides tragacanth gum fed at a level of
3% along with 3% cholesterol in the diet of cockerels, inhibited the
development of hypercholesterolemia (Riccardi & Fahrenback, 1965).
Tragacanth gum administered intraperitoneally, subcutaneously or
per os 24 hours before hexobarbital has no effect on the
hexobarbital sleeping time of mice. The effect of phenobarbital and
urethan pre-treatment to induce a shortening of hexobarbital sleeping
is blocked by intraperitoneal injections of tragacanth gum, thus
suggesting the presence of a hepatic effect of tragacanth gum
(Fujimoto, 1965).
TOXICOLOGICAL STUDIES
Special studies on sensitization
Although there are only few reports of sensitization to
tragacanth, the available information indicates tragacanth is a
powerful allergen capable of causing extremely severe reactions
(Gelfand, 1943). Allergic response may occur as a result of inhalation
or oral ingestion (Gelfand, 1949).
Special studies on teratogenicity
Mouse
Intraperitoneal injection of 1 ml 1% aqueous mucilage of Persian
tragacanth (single dose or five doses of 0.2 ml) into mice between
days 11 and 15 of gestion caused the death of all fetuses. Oralor s.c.
administration had no effect. All samples were found to be
contaminated with enterobacter spp. and the embryotoxic effects were
attributed to bacterial metabolites (Frohberg et al., 1969).
Acute toxicity
None available.
Short-term studies
None available.
Long-term studies
None available.
Comments:
Little toxicological information is available despite the
traditional use of this substance in pharmaceutical preparations. The
metabolic fate of this gum should be studied in several species,
preferably including man. Ninety-day studies in several species are
also required. The teratogenicity study points to the need for careful
attention to the microbiological contamination of these natural gums.
EVALUATION
Not possible on the data available.
REFERENCES
Frohberg, H., Oettel, H. & Zeller, H. (1969) Arch. Toxikol., 25, 268
Fujimoto, J. M. (1965) Toxicol. appl. Pharmacol., 7, 287-290
Gelfand, H. H. (1943) J. Aller., 14, 203
Gelfand, H. H. (1949) J. Aller., 20, 311
Riccardi, B. A. & Fahrenbach, M. J. (1965) Fed. Proc., 24, 263