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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
Study period:
1988
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The study methodology followed was equivalent or similar to OECD TG 471 and the study was conducted in accordance with the Principles of Good Laboratory Practice (GLP)
Cross-referenceopen allclose all
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1988
Report date:
1988

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Principles of method if other than guideline:
not applicable
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
Butyl propionate
EC Number:
209-669-5
EC Name:
Butyl propionate
Cas Number:
590-01-2
Molecular formula:
C7H14O2
IUPAC Name:
butyl propanoate
Details on test material:
- Name of test material (as cited in study report): n-butyl propionate
- Physical state: colourless, clear liquid
- Analytical purity: 99.825%
- Lot/batch No.: Ref. PRP/139/88
- Stability under test conditions: to be stable < 7.5 hours
- Storage condition of test material: stored in the dark at room temperature

Method

Target gene:
The bacterial reverse mutation test uses amino-acid requiring strains of Salmonella typhimurium and Escherichia coli to detect point mutations, which involve substitution, addition or deletion of one or a few DNA base pairs. The principle of this bacterial reverse mutation test is that it detects mutations which revert mutations present in the test strains and restore the functional capability of the bacteria to synthesize an essential amino acid. The revertant bacteria are detected by their ability to grow in the absence of the amino acid required by the parent test strain.
Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Details on mammalian cell type (if applicable):
- Type and identity of media: For detecting revertants of both the Salmonella and Escherichia tester strains, ready poured petri plates containing 25 ml of minimal agar medium were obtained form Gibco Europe Ltd., Paisley, Scotland.
- Properly maintained: yes
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
S9
Test concentrations with justification for top dose:
31.25, 62.5, 125, 250, 500, 1000, 2000 and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: acetone
- Justification for choice of solvent/vehicle: recommended vehicle by various regulatory agencies
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
no
True negative controls:
yes
Positive controls:
yes
Positive control substance:
other: Potassium dichromate, Benzo(a)pyrene, Sodium azide, 2-Aminoanthracene, 9-Aminoacridine, Neutral red and 2-Nitrofluorene
Details on test system and experimental conditions:
METHOD OF APPLICATION: in agar (plate incorporation) - 20 µl volumes of solutions of n-butyl propionate in acetone (1.56, 3.125, 6.25, 12.5, 25, 50, 100 or 250 mg/ml) were added to top agar mix to give final amounts of 31.25, 62.5, 125, 250, 500, 1000, 2000 or 5000 µg per plate both in the presence and in the absence of rat liver S9 fraction. The cultures were incubated at 37°C for 48-72 h before the revertant colonies were counted
Evaluation criteria:
There are several criteria for determining a positive result, such as a concentration-related increase over the range tested and/or a reproducible increase at one or more concentrations in the number of revertant colonies per plate in at least one strain with or without metabolic activation system. Biological relevance of the results should be considered first.
Statistics:
Standard statistical methods were employed

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:
no cytotoxicity
Vehicle controls validity:
not applicable
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
The test compound formed oily smears on the surface of the top agar at 5000 µg per plate showing that it was not miscible in the aqueous test system at this amount.The addition of 2500 µg per ml n-butyl propionate (equivalent to approx. 5000 µg per plate) caused the pH of the medium to change from 7.30 to 7.29.
Microscopical evaluation of the background lawn showed no evidence of cytotoxicity at amounts up to 5000 µg n-butyl propionate per plate either in the presence or in the absence of rat liver S9 fraction. The addition of n-butyl propionate to agar layer cultures of Salmonella tvphimurium TA 1535, TA 1537, TA 1538, TA 98 or TA 100 or Escherichia coli WP2 uvrA pKM101 did not increase the reverse mutation frequency in any of the strains either in the presence or in the absence of rat liver S9 fraction.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

None

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

Under the conditions of the study, it was concluded that n-butyl propionate did not induce reverse gene mutation in the selected bacterial tester strains and hence based on the Guidance to Regulation (EC) No. 1272/2008 on Classification, Labelling and Packaging of substances and mixtures, n-butyl propionate will not be classified for genotoxicity.
Executive summary:

The mutagenic activity of n-butyl propionate was investigated in agar layer cultures of selected bacterial tester strains of Salmonella typhimurium and Escherichia coli. Assays were performed both in the presence and in the absence of an S9 microsomal fraction obtained from a liver homogenate from rats pre-treated with Aroclor 1254.

Under the conditions of the study, it was concluded that n-butyl propionate did not induce reverse gene mutation in the selected bacterial tester strains and hence based on the Guidance to Regulation (EC) No. 1272/2008 on Classification, Labelling and Packaging of substances and mixtures, n-butyl propionate will not be classified for genotoxicity.