Registration Dossier

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

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:
2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant guideline study, available as unpublished report, no restrictions, fully adequate for assessment

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2006
Report Date:
2006

Materials and methods

Test guidelineopen allclose all
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 472 (Genetic Toxicology: Escherichia coli, Reverse Mutation Assay)
Deviations:
no
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Test Substance Code: HR6750
Supplier: International Flavors & Fragrances (Japan) Ltd.
Purity: 100%
Appearance: colorless to pale yellow liquid

Method

Target gene:
Salmonella typhimurium strains TA100, TA1535, TA98 and TA1537 and Escherichia coli strain WP2uvrA were used. Salmonella typhimurium strains and Escherichia coli strain were supplied from Dr. Taijiro Matsushima, Japan Bioassay Research Center, on March 13, 2003 and on September 20, 2003, respectively.
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
not specified
Species / strain / cell type:
E. coli WP2 uvr A
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
phenobarbital and 5,6-benzoflavone induced rats livers: S9
Test concentrations with justification for top dose:
A highest dose of 78.1 μg/plate (based on the observed bacterial growth inhibition) and lower 5 doses of 39.1, 19.5, 9.77, 4.88 and 2.44 μg/plate (diluted in a geometric progression of 2) were employed without S9 mix in the main test. In the groups with S9 mix, a highest dose of 313 μg/plate (based on the observed bacterial growth inhibition) and lower 5 doses of 156, 78.1, 39.1, 19.5 and 9.77 μg/plate (diluted in a geometric progression of 2), were employed.
Vehicle / solvent:
DMSO
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
sodium azide
Remarks:
AF2, ICR-191 and 2AA
Details on test system and experimental conditions:
After 0.1 mL of the test substance solution, solvent or the positive control solution, 0.5 mL of 0.1 M sodium phosphate buffer (pH 7.4) or S9 mix and 0.1 mL of the bacterial culture were added to a test tube, the mixture was shaken at 37±0.5°C for 20 minutes. Two milliliters of the soft agar were then added to each tube and the mixture was poured onto a minimal glucose agar plate. The number of revertant colonies was counted after incubation at 37±0.5°C for 48 hours.

For the plates in which the bacterial growth inhibition was observed, the number of colonies was counted with a manual counter, and the other plates were counted by using a colony analyzer (CA-IID, System Science Ltd.)
Evaluation criteria:
The test substance was judged positive when the number of revertant colonies increased to twice or more that in the negative control in a concentration-dependent manner and also the reproducibility of the test results was obtained. In all other cases, it was judged negative.
Statistics:
Any statistical methods were not used.

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
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:
not examined
Positive controls validity:
valid
Additional information on results:
The number of revertant colonies in the test substance treatment groups was less than twice that in the solvent control in the groups with and without S9 mix. The bacterial growth inhibition was observed at 78.1 ug/plate in all test strains without S9 mix and more than 156 ug/plate in TA100, TA1535, TA98 and TAl537 and at 313 ug/plate in WP2uvrA with S9 mix. The precipitation of the test substance was not observed at any doses in the groups with and without S9 mix.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

The test substance was judged negative because the number of the revertant colonies in the test substance treatment groups in all test strains was less than twice that in the negative control regardless of the presence or absence of S9 mix. It was concluded that D. Damascone had no ability to induce mutations under the present test conditions.

Applicant's summary and conclusion