2-(1,1-dimethylpropyl)phenol

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Japanese Ministry of Health study. Well documented study performed to the principles of OECD guideline 471. No GLP status.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2001

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

not specified

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

2-tert.-butylphenol

IUPAC Name:

2-tert.-butylphenol

Constituent 2

Reference substance name:

2-tert-butylphenol

EC Number:

201-807-2

EC Name:

2-tert-butylphenol

Cas Number:

88-18-6

Molecular formula:

C10H14O

IUPAC Name:

2-tert-butylphenol

Constituent 3

Reference substance name:

o.-tert.-butylphenol

IUPAC Name:

o.-tert.-butylphenol

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): 2-tert.-butylphenol
- Physical state: liquid
- Analytical purity: 99.97%
- Purity test date: 2014-05-07
- Lot/batch No.: 1419
- Expiration date of the lot/batch: 05/2015
- Stability under test conditions: stable
- Storage condition of test material: under N2 in tightly closed container at a cool, well ventilated place
- Colour: clear

Method

Species / strain

Species / strain / cell type:

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

Metabolic activation:

with and without

Metabolic activation system:

phenobarbital and 5,6-benzoflavone induced rat liver S9

Test concentrations with justification for top dose:

The test solutions were prepared at the time of use.
Dose-finding test - 50 to 5000 μg/plate.
Main test - 200 μg/plate at maximum and 100, 50, 25, 12.5 and 6.25 μg/plate using a common ratio of 2.

Vehicle / solvent:

DMSO
Test material not soluble in water

Controls

Negative solvent / vehicle controls:

yes

Positive controls:

yes

Positive control substance:

9-aminoacridine

sodium azide

furylfuramide

other: 2-aminoanthracene

Details on test system and experimental conditions:

The study was conducted by the pre-incubation method.

To a test tube, 0.1 mL of the solvent, test article solution or positive control article solution, 0.5 mL of 0.1 M sodium phosphate buffer (pH 7.4) for the direct method or 0.5 mL of S9 mix for the metabolic activation method, and then 0.1 mL of bacterial suspension were added and cultured with
shaking for 20 minutes at 37°C. Then, the mixture to which 2 mL of top agar was added and warmed to 45°C was overlaid on the plate. After the end of cultivation for 48 hours at 37°C, the number of revertant colonies was counted and the presence or absence of growth inhibition of the indicator bacterial strains was observed simultaneously using a stereomicroscope. The number of plates used was one for each dose concentration in the
dose selection test and three for each dose concentration in the main test. The main test was conducted twice using the same dose concentrations.

Evaluation criteria:

If the number of revertant colonies (mean value) in the test article-treated plate was at least twice that of the vehicle control plate and dose dependency and reproducibility of the results were observed, the test article was judged to be positive.

Results and discussion

Test results

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

RANGE-FINDING/SCREENING STUDIES: Growth inhibition of bacteria was observed at the dose levels of 200 μg/plate and above for all bacterial
strains irrespective of the presence or absence of metabolic activation, and slight growth inhibition was observed at 100 μg/plate in the direct
method for TA100, TA1535 and TA1537.

Remarks on result:

other: all strains/cell types tested

Applicant's summary and conclusion

Conclusions:

Based on the results described above, it was judged that o-tert-butylphenol was negative for gene mutation inducibility under the conditions of this experiment

Executive summary:

In a study reported by the Japanese Ministry of Health, o-tert butyl phenol in DMSO (concentrations 6.25 to 200 μg/plate) was tested using the pre-incubation method in the absence (direct method) or presence (metabolic activation method) of S9 mix usingSalmonella typhimuriumTA100, TA1535, TA98, TA1537 andEscherichia coliWP2uvrAas index bacterial strains.

Under the conditions of this experiment, o-tert butyl phenol was not mutagenic.