2,4,6-tribromophenol

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

2,4,6-tribromophenol

EC Number:

204-278-6

EC Name:

2,4,6-tribromophenol

Cas Number:

118-79-6

Molecular formula:

C6H3Br3O

IUPAC Name:

2,4,6-tribromophenol

Test material form:

solid: granular

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: MANAC, Hiroshima, JAPAN; Lot No.: 70909
- Purity test date: 99.8 %
- Storage conditions: cold storage, closed vessel, in the dark

Method

Target gene:

His
Trp

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

S9; liver homogenate obtained from male rats after induction with phenobarbital and benzoflavone

Test concentrations with justification for top dose:

Preliminary test to find the cytotoxic concentration:
- without S9 mix:
500 µg/plate and greater for TA100, TA1535, and TA98
1500 µg/plate and greater for TA 1537
5000 µg/plate for WP2 urvA
- with S9 mix:
500 µg/plate and greater for TA100, TA1535, and TA1537
1500 µg/plate and greater fot TA 98
5000 µg/plate for WP2 urvA

Main test concentration:
- without S9 mix:
0, 15.6, 31.3, 62.5, 125, 250, 500 µg/plate for S. typhimurium TA100, TA1535, and TA98
0, 31.3, 62.5, 125, 250, 500, 1000 µg/plate for S. typhi. TA1537
0, 156, 313, 625, 1250, 2500, 5000 µg/plate for E.coli. WP2 urvA
- with S9 mix:
0, 15.6, 31.3, 62.5, 125, 250, 500 µg/plate for S. typhimurium TA100, TA1535, and TA1537
0, 15.6, 31.3, 62.5, 125, 250, 500, 1000 µg/plate for S. typhimurium TA 98
0, 156, 313, 625, 1250, 2500, 5000 µg/plate for E. coli. WP2 urvA

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

2-acetylaminofluorene

9-aminoacridine

sodium azide

other: +S9 mix: 2-Aminoanthracene for WP2 uvrA, TA1535, TA1537, TA100, TA98

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Preincubation period: 20 minutes
- Exposure duration: 48 hours at 37°C

DETERMINATION OF CYTOTOXICITY
- Method: stereomicroscope to judge condition of bacterial membrane on agar surface

Evaluation criteria:

A positive (mutagenic) response in this test system is defined as the average number of colonies on the plate containing the test material being more than twice the number growing on plates containing solvent only in at least one of the bacterial strains. The response should be reproducible and dose dependent.

Statistics:

The average and standard deviation of each dose level were calculated.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Growth inhibition was observed at 500 µg/plate.

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Growth inhibition was observed at 500 µg/plate

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Growth inhibition was observed at 500 µg/plate.

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 4

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Growth inhibition was observed at 500 µg/plate.

Vehicle controls validity:

valid

Positive controls validity:

valid

Test results 5

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Growth inhibition was observed at 2500 µ/plate

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

The results showed that the increase of the number of revertant colonies of all strains against the solvent control did not exceed the 2-fold criterion for a positive result, and therefore the test results were negative.

Applicant's summary and conclusion

Conclusions:

No increase in mutation frequency was detected in this study using the criterion that a positive result would be defined as a two-fold increase in colonies compared to the solvent control. All positive controls increased mutation frequency, and the solvent control fell within historical levels.
2,4,6 -tribromophenol is not mutagenic according to the conditions of this study.