Registration Dossier

Administrative data

Endpoint:
additional toxicological information
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
4 (not assignable)

Data source

Reference
Reference Type:
review article or handbook
Title:
The Metabolism of Azo Compounds: A Review of the Literature
Author:
R. Walker
Year:
1970
Bibliographic source:
Food and Cosmetics Toxicology, Vol. 8, pp. 659-676

Materials and methods

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Type:
Constituent
Type:
Constituent
Type:
Constituent
Details on test material:
In the review of Walker, especially the metabolism of the two substances CAS 1934-21-0 and 2783-94-0 are of interest.

Results and discussion

Any other information on results incl. tables

Summarising all studies, it is apparent that both substances when applied orally are rapidly and almost completely metabolised to sulphanilic acid.

In particular, Roxon, Ryan & Wright (1966) isolated from rat-gut contents a Proteus sp. capable of reducing tartrazine. The same authors extended these studies using whole cells and cell-free extracts of Proteus vulgaris isolated from rat-intestinal contents (1967a)

and found an in vitro reduction of 37.5% in 4 hours fo CAS 1934-21-0 (1967b).

Roxon, Ryan, Welling & Wright (1967) demonstrated that the same substance is cleaved to p-sulphophenylhydrazine and sulphanilic acid.

Daniel (1962) showed in a rabbit study that sulphanilic acid was excreted vai the urine in amount equivalent to 77% (CAS 2783 -94 -0) and 96% (CAS 1934-21-0).

Literature:

Daniel, J. W. (1962). The excretion and metabolism of edible food colors. Toxic. appl. Pharmac. 4, 572.

Roxon, J. J., Ryan, A. J., Welling, P. G. & Wright, S. E. (1967). Origin of ui'inary sulphanilic acid from tartrazine. Fd Cosmet. Toxicol. 5, 447.

Roxon, J. J., Ryan, A. J. & Wright, S. E. (1966). Reduction of tartrazine by a Proteus species isolated from rats. Fd Cosmet. Toxicol. 4, 419.

Roxon, J. J., Ryan, A. J. & Wright, S. E. (1967a). Enzymatic reduction of tartrazine by Proteus vulgaris from rats. Fd Cosmet. Toxicol. 5, 645.

Roxon, J. J., Ryan, A. J. & Wright, S. E. (1967b). Reduction of water-soluble azo dyes by intestinal bacteria. Fd Cosmet. Toxicol. 5, 367.

Applicant's summary and conclusion

Conclusions:
Both azo compounds CAS 1934-21-0 and CAS 2783-94-0 are rapidly and almost completely metabolised in the gut. They are metabolised by gut flora to sulphanilic acid and a specific rest (p-sulphophenylhydrazine and 1-amino-2-naphthol-6-sulphonic acid, respectively).
Executive summary:

Both azo compounds CAS 1934-21-0 and CAS 2783-94-0 are rapidly and almost completely metabolised in the gut. They are metabolised by gut flora to sulphanilic acid and a specific rest (p-sulphophenylhydrazine and 1-amino-2-naphthol-6-sulphonic acid, respectively).