4-[[2-methoxy-4-[(4-nitrophenyl)azo]phenyl]azo]phenol

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Ames test

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1991

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1991

Report date:

1991

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

4-[[2-methoxy-4-[(4-nitrophenyl)azo]phenyl]azo]phenol

EC Number:

243-325-5

EC Name:

4-[[2-methoxy-4-[(4-nitrophenyl)azo]phenyl]azo]phenol

Cas Number:

19800-42-1

Molecular formula:

C19H15N5O4

IUPAC Name:

4-[[2-methoxy-4-[(4-nitrophenyl)azo]phenyl]azo]phenol

Method

Target gene:

histidine

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Metabolic activation system:

S-9 fraction (rat liver homogenate)

Test concentrations with justification for top dose:

0, 4, 20, 100, 500, 2500 and 5000 µg/plate
(3 test plates per dose or per control)

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

yes

Positive controls:

yes

Positive control substance:

9-aminoacridine

other: 2-aminoanthracene, N-methyl-N'-nitro-N-nitroso-guanidine, 4-nitro-o-phenylenediamine

Details on test system and experimental conditions:

To 2 mL of molten top agar in a sterile test-tube, were added 0.1 mL of the tester strain culture, graded quantities of the test substance in 0.1 mL solution and, for the S-9 series, 0.5 mL of S-9 Mix. The contents of the test-tube were rapidly mixed and poured onto the surface of previously prepared minimal agar plates with Vogel-Bonner E mixture. The plate were incubated upside down at 37°C for 2 days, after which the number of revertants colonies appearing was counted.

Evaluation criteria:

Doubling of the spontaneous mutation rate (control)

Results and discussion

Test results

Key result

Species / strain:

other: Salmonella typhimurium TA98, TA100, TA1535, and TA1537

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Positive and negative controls were valid

Any other information on results incl. tables

Without metabolic activation:

TA1535: Weakly positive reaction at 5000 µg/plate (factor 3.0). TA100: Mutagenicity was observed over a dose range of 500 µg - 5000 µg/plate (factor 2.4 - 5.3). TA1537: Positive reaction from about 20 µg/plate (factor 2.11 onward with an increase in the number of his revertants by a factor of 21.3 at 5000 µg/plate. TA98: A positive reaction was detected from about 20 µg/plate (factor 2.9 3.21 onward; increase in the number of mutant colonies by a factor of 31.2 at 5000 µg/plate).

With metabolic activation:

TA1535: Slight increase in the number of mutant colonies at 500 µg - 5000 µg/plate (factor 2.4 - 3.7). TA100: Weakly positive reaction from about 100 µg/plate (factor 1 .6) onward up to 5000 µg/plate (factor 5.8). TA1537: Increase in the number of mutant colonies from about 100 µg/plate (factor 4.3) onward up to 2500 µg - 5000 µg/plate (factor 17.5 - 18 .0). TA98: Mutagenicity was observed from about 20 µg/plate (factor 3.0 - 3.3) onward with a maximum increase in the number of his revertants by a factor of 39.4 at 2500 µg/plate in the 1st experiment.

Applicant's summary and conclusion

Conclusions:

Under the study conditions, the test substance was considered to be mutagenic in Salmonella typhimurium TA98, TA100, TA1535, and TA1537.

Executive summary:

A study was conducted to determine the mutagenic potential of the test substance (in the form of a powder of 94.5% purity) according to OECD Guideline 471. Four strains of Salmonella typhimurium (TA98, TA100, TA1535 and TA1537) were exposed to the test substance at concentrations of 4.0 to 5000.0 µg/plate with or without metabolic activation (S-9 Mix) for 48 h. Negative and positive controls were valid. The test substance with and without metabolic activation induced mutagenic activity in bacteria; the number of revertants was greater than twice the number of spontaneous mutations. Under the study conditions, the test substance was considered to be mutagenic (Engelbart, 1991).