3'-(trifluoromethyl)acetophenone

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:

July - September 1998

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Version / remarks:

1992

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

1983

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

3'-(trifluoromethyl)acetophenone

EC Number:

206-490-4

EC Name:

3'-(trifluoromethyl)acetophenone

Cas Number:

349-76-8

Molecular formula:

C9H7F3O

IUPAC Name:

1-[3-(trifluoromethyl)phenyl]ethan-1-one

Test material form:

liquid

Specific details on test material used for the study:

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Solubility and stability of the test substance in the solvent/vehicle: To demonstrate that the test system was exposed to the intended concentrations of the test substance in the mutagenicity tests, the concentration of the substance in solution has been determined by the analytical unit. The analysis was performed with the lowest concentration, which was obtained by serial dilution of the highest concentration used.

Method

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

rat liver S9 fraction

Test concentrations with justification for top dose:

20.58, 61.73, 185.19, 555.56, 1666.67, 5000 µg / plate in the range finding test
312.5 to 5000.0 ug/plate (original and conformatory experiment)

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: with :2-Aminoanthracene for TA 100, TA 102, TA 98, TA 1537, Cyclophosphamide for TA 1535, without : Sodium azide for TA 100 and TA 1535, Mitomycin-C for TA 102, 2-Nitrofluorene for TA 98, 9-Aminoacridine for TA 1537, 4-nitroquinoline for WP2 uvrA

Rationale for test conditions:

Range finding test
Six concentrations of the test item ranging from 20.6 to 5000.0 µg/plate were tested with strain Salmonella typhimurium TA100 and strain Escherichia coli WP2 uvrA to determine the highest concentration to be used in the mutagenicity assay. The experiments were performed with and without metabolic activation. Normal background growth was observed with both strains. The numbers of revertant colonies were not reduced. The test substance did not precipitate on thesurface of the agar plates.
From the results obtained the highest concentration suitable for the mutagenicity test was selected to be 5000.0 µg/plate with and without metabolic activation.

Evaluation criteria:

The test substance will be considered to be positive in the test system if one or both of thefollowing conditions are met:
• At least a reproducible doubling of the mean number of revertants per plate above that of the negative control at any concentration for one or more of the following strains: TA 98, TA 1535, TA 1537, E. coli WP2 uvrA.
• A reproducible increase of the mean number of revertants per plate for any concentration above that of the negative control by at least a factor of 1.5 for strains TA 100 or TA 102.
Generally a concentration-related effect should be demonstrable.

Statistics:

A statistical analysis was not performed. At present the use of statistical methods concerning this particular test system is not generally recommended.

Results and discussion

Test results

Test results 1

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

not applicable

Positive controls validity:

valid

Test results 2

Species / strain:

other: S. typhimurium TA 98, TA 100, TA 102; TA 1535, TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

True negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

Due to a growth inhibiting effect of the test substance the number of revertant colonies was reduced in the original experiment with metabolic activation on strains TA 100, TA 102, TA 1537 (2500.0 and 5000.0 µg/plate), TA 1535 and TA 98 (5000.0 µg/plate). In the experiment without activation a reduction in the number of reverant colonies was observed with strains TA 100, TA 102, TA 98, TA 1537 (2500.0 and 5000.0 µg/plate) and TA 1535 (5000.0 µg/plate). Similar effects occurred in the confirmatory experiment with activation on strains TA 100, TA 1537 (2500.0 and 5000.0 µg/plate), TA 1535, TA 102, TA 98 and E. coli (5000.0 µg/plate). In the
experiment without activation a reduction in the number of reverant colonies was seen with strains TA 100, TA 1535, TA 102, TA 1537 (2500.0 and 5000.0 µg/plate) and TA 98 (5000.0 µg/plate). A reduction in the growth of the background lawn was observed in the experiments with activation on strains of S. typhimurium at the higher concentrations. In the experiments without activation also on strain E. coli a reduced growth was visible. The test substance did not precipitate on the surface of the agar plates.

Remarks on result:

other: negative

Applicant's summary and conclusion

Executive summary:

The test item was tested for mutagenic effects in vitro according to OECD TG 471 in S. typhimurium TA98, TA 100, TA 102, TA 1535, TA 1537 and E. coli WP2 uvrA. The test was performed with and without the addition of rat-liver post mitochondrial supernatant (S9 fraction). The compound was dissolved in DMSO and tested at five concentrations in the range of 312.5 to 5000.0 µg/plate in the presence and absence of a metabolic activation system. In order to confirm the results, the experiments were repeated with and without metabolic activation at five concentrations in the range of 312.5 to 5000.0 ng/plate. Each strain was additionally tested in the presence and in the absence of a metabolic activation system with a suitable, known mutagen as positive control. The original experiment with and without metabolic activation and the confirmatory experiment without activation were performed as standard plate incorporation assay. The confirmatory experiments with metabolic activation were carried out as preincubation assay.

In both experiments, performed with and without metabolic activation, none of the tested concentrations of the test item led to an increase in the incidence of either histidine or tryptophan-prototrophic mutants by comparison with the negative control. Based on the results of these experiments, it is concluded that the test item and its metabolites did not induce gene mutations.