Methyl N-ethyl-N-[4-[(5-nitro-2,1-benzisothiazol-3-yl)azo]phenyl]-β-alaninate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

Dec 1983 / Jan 1984

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1984

Report date:

1984

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Principles of method if other than guideline:

Ames BN, Durston WW, Yamasaki E, Lee FD. Carcinogens are mutagens: A simple test system combining liver homogenates for activation and bacteria for detection. Proc.Nat.Acad.Sci. USA 1973:70:2281-2285
Ames BN, McCann J, Yamasaki E. Methods for detecting carcinogens and mutagens with the Salmonella/mammalian-microsome mutagenicity test. Mut.Res. 1975:31:347-364.

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Methyl N-ethyl-N-[4-[(5-nitro-2,1-benzisothiazol-3-yl)azo]phenyl]-β-alaninate

EC Number:

257-779-7

EC Name:

Methyl N-ethyl-N-[4-[(5-nitro-2,1-benzisothiazol-3-yl)azo]phenyl]-β-alaninate

Cas Number:

52239-04-0

Molecular formula:

C19H19N5O4S

IUPAC Name:

methyl N-ethyl-N-[4-[(5-nitro-2,1-benzisothiazol-3-yl)azo]phenyl]-β-alaninate

Test material form:

solid

Method

Species / strain

Species / strain 1

Species / strain / cell type:

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

Additional strain / cell type characteristics:

other: histidine dependent

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1538

Additional strain / cell type characteristics:

other: histidine dependent

Metabolic activation:

with and without

Metabolic activation system:

rat liver homogenate induced with Aroclor 1254

Test concentrations with justification for top dose:

TA 98: 0.016 - 5000 µg/plate
all other strains: 20 - 5000 µg/plate

Vehicle / solvent:

DMSO

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

with S9-mix: S. typhimurium TA 1535, TA 1537, TA 1538, TA 98 and TA 100

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: N-methyl-N-nitro-N-nitrosoguanidine

Remarks:

w/o S9-mix: TA 100, TA 1535

Controls 3

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-Nitro-o-phenylendiamine

Remarks:

w/o S9-mix: TA 98, TA 1538

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 9-Aminoacridiniumchloride monohydrate

Remarks:

w/o S9-mix: TA 1537

Results and discussion

Test results

Test results 1

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

in TA100, TA1537 and TA98 >= 2500 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Remarks:

2500 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Any other information on results incl. tables

Test item was dissolved in DMSO.

Precipitation occurred at 2500 µg/plate and above.

Applicant's summary and conclusion

Conclusions:

The test item was found to be strongly mutagenic in the Ames test with Salmonelly typhimurum TA1535, TA100, TA1537, TA1538 and TA98 with and without metabolic activation (S9 mix).

Executive summary:

The mutagenic activity of Disperse Blue 148 (95.2% purity),was investigated in a plate incorporation test using the Salmonella typhimurium strains TA 1535, TA 1537, TA 1538, TA 98, and TA 100. The test article was tested at the concentrations between 0.016 and 5000 µg/plate for TA 98 and 20 and 5000 µg/plate for the remaining cells.

Incomplete solubility of the test substance in DMSO was observed from 2500 µg/plate onward. Distinct toxic effects, evidenced by a reduction in spontaneous or induced revertant colonies, occurred with and without S9 mix in strains TA 100, TA 1537 and TA 98 at concentrations ≥ 2500 μg/plate. Reproducible, dose-dependent increases in revertant colony numbers were obtained with all tester strains with and without S9 mix. Appropriate reference mutagens were used as positive controls and showed a distinct increase of induced revertant colonies.

In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test article induced gene mutations by base pair changes and frameshifts in the genome in all tested strains.