Dibromodibenzo[b,def]chrysene-7,14-dione

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:

key study

Study period:

November 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)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

dibromodibenzo[b,def]chrysene-7,14-dione

EC Number:

215-363-2

Cas Number:

1324-11-4

Molecular formula:

C24H10Br2O2

IUPAC Name:

dibromodibenzo[b,def]chrysene-7,14-dione

Test material form:

solid: particulate/powder

Details on test material:

Vat Orange 1

Method

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1538

Metabolic activation:

with and without

Metabolic activation system:

rat S9-mix induced with Aroclor 1254

Test concentrations with justification for top dose:

4, 20, 100, 500, 2500, 5000 µg/plate
In a range finding study, concentrations from 4 to 10000 µg/plate were tested. No cytotoxicity was observed. From 500 µg/plate onnwards precipitation was observed.

Vehicle / solvent:

DMSO

Controls

Controls 1

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

benzo(a)pyrene

other: 2-aminoanthracene

Remarks:

all strains with S9

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

TA 100, TA1535 w/o S9

Controls 3

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

TA1537 w/o S9

Controls 4

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

TA 98, TA 1538 w/o S9

Controls 5

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG)

Remarks:

WP2uvrA w/o S9

Details on test system and experimental conditions:

Two independent mutagenicity tests were formed. In both cases top agar is prepared for the Salmonella strains by mixing 100 ml agar (0.6% agar, 0.5 % NaCl) with 10 ml of a 0.5 mM histidine-biotin solution. The following ingredients are added (in order) to 2 ml of molten top ager at 45°C:
0.1 ml of an overnight nutrient broth culture of the bacterial tester strain
0.1 ml test compound solution
0.5 ml S-9 Mix (if required) or buffer
After mixing, the liquid is poured into a petridish with minimal agar (1.5 % agar, Vogel-Bonner E medium with 2 % glucose). After incubation for 48 to 72 hours at 37°C in the dark, colonies (his+ revertants) are counted.

Evaluation criteria:

Cytotoxicity: reduced growth rate or thinning of bacterial lawn
Positive: - dose-related and reproducible increase in number of revertant colonies
- doubling of spontaneous mutation rate in at least one tester strains either with or without S9

Statistics:

NA

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium, other: S. typhimurium TA 1535, TA 1537, TA 1538, TA 98, TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

The test compound did not cause a significant increase in the number of revertant colonies with any of the tester strains neither in the absence nor presence of S-9 Mix. No dose dependent effect was obtained.
It is concluded that the test substance is not mutagenic in these bacterial test systems neither in the absence nor in the presence of an exogenous metabolizing system.
This test was performed according to the methods described. No unforeseen circumstances were observed which have affected the quality and integrity of this study.
This study was conducted in compliance with the principles of good laboratory practice.

Applicant's summary and conclusion

Conclusions:

Vat Orange 1 is not mutagenic in this bacterial test system either with or without exogenous metabolic activation at the dose levels investigated.

Executive summary:

Vat Orange 1 was tested for mutagenicity with the strains TA 100, TA 1535, TA 1537, TA 1538, TA 98 of Salmonella typhimurium and Escherichia coli WP2uvrA.

The mutagenicity studies were conducted in the absence and in the presence of a metabolizing system derived from rat liver homogenate. A dose range of 6 different doses from 4 µg/plate to 5 000 µg/plate was used.

Control plates without mutagen showed that the number of spontaneous revertant colonies was similar to that described in the literature. All the positive control compounds gave the expected increase in the number of revertant colonies.

Toxicity: The test compound proved to be not toxic to the bacterial strains. 5 000 µg/plate was chosen as top dose level for the mutagenicity study.

Mutagenicity: In the absence of the metabolic activation system the test compound did not show a dose dependent increase in the number of revertants in any of the bacterial strains. Also in the presence of a metabolic activation system, treatment of the cells with Vat Orange 1 did not result in relevant increases in the number of revertant colonies.

Summarizing, it can be stated that Vat Orange 1 is not mutagenic in these bacterial test systems neither with nor without exogenous metabolic activation at the dose levels investigated.