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Toxicological information

Genetic toxicity: in vitro

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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: Meets generally accepted scientific standards, well documented and acceptable for assessment.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes
Type of assay:
bacterial forward mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:

- Physical state: grey/green powder
- Analytical purity: 96%
- Lot/batch No.: 104
- Storage condition of test material: at 13 °C protected from light.

Method

Target gene:
several S. typhimurium strains
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Metabolic activation system:
rat liver microsomal preparation (S9-mix)
Test concentrations with justification for top dose:
0, 25, 79, 250, 790, 2500 µg/ml
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: water containing 0.15 % agar
Controls
Untreated negative controls:
yes
Remarks:
sterility control
Negative solvent / vehicle controls:
yes
Remarks:
distilled water containing 0.15 % agar
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: benzo[a]pyrene, 2-nitrofluorene, 2-aminoanthracene, 9-aminoacridine and sodium azide
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 2 days

NUMBER OF REPLICATIONS: 3
Evaluation criteria:
The assessment for the test was based on the number of revertant colonies per plate. In general, a substance to be characterized as positive in the Ames test has to fulfill the following requirements:
- doubling of the spontaneous mutation rate (control);
- dose-response relationship;
- reproducibility of the results.

Results and discussion

Test results
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
Remarks:
from 2500 µg/plate onwards
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

No increases in revertant colony numbers were obtained with any of the four bacterial strains tested, either in the presence or absence of S-9 mix. Inhibition of growth, observed as thinning of the background lawn of non-revertant cells and reduction in revertant colony numbers, occurred in all strains following exposure to 2500 µg per plate.

Marked increases in the number of revertant colonies were induced by the known mutagens benzo[a]pyrene, 2-nitrofluorene, 2-aminoanthracene, 9-aminoacridine and sodium azide when examined under similar conditions.


It was concluded that the test substance was devoid of mutagenic activity under the conditions of the test.

Applicant's summary and conclusion