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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
2001
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2001
Report date:
2001

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Qualifier:
according to guideline
Guideline:
JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals
Version / remarks:
T31-18: Chemical Substance Control Law of Japan
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay

Test material

Constituent 1
Chemical structure
Reference substance name:
2-ethylbutyric acid
EC Number:
201-796-4
EC Name:
2-ethylbutyric acid
Cas Number:
88-09-5
Molecular formula:
C6H12O2
IUPAC Name:
2-ethylbutyric acid
Test material form:
not specified

Method

Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
S9-mix
Test concentrations with justification for top dose:
0, 313, 625, 1250, 2500, 5000 µg/plate
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
no
True negative controls:
no
Positive controls:
yes

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
At 5000 ug/plate with metabolic activation
Vehicle controls validity:
not applicable
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
At 5000 ug/plate with metabolic activation
Vehicle controls validity:
not applicable
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
At 5000 ug/plate with metabolic activation
Vehicle controls validity:
not applicable
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
At 5000 ug/plate with metabolic activation
Vehicle controls validity:
not applicable
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
No gene mutation was observed in any Salmonella typhimurium or Escherichia coli strain, however, microbial toxicity was observed at 5000 µg/plate in Salmonella typhimurium TA1535, TA1537, TA98, and TA100 with metabolic activation.

Applicant's summary and conclusion

Conclusions:
2-Ethylbutyric acid was concluded not to be mutagenic with and without metabolic activation in Salmonella typhimurium and Escherichia coli at ≤5000 µg/plate.
Executive summary:

A bacterial reverse mutation assay (Ames test) was performed to determine the genetic toxicity of 2-ethylbutyric acid at 0, 313, 625, 1250, 2500, 5000 µg/plate. The following species and strains were exposed for the purpose of the experiment, with and without metabolic activation (S9-mix): Salmonella typhimurium TA1535, TA1537, TA98, and TA100 and Escherichia coli WP2 urvA. Positive and negative (dimethyl sulfoxide solvent) control groups were prepared and run in parallel. The experiment was undertaken according to Good Laboratory Practise (GLP), OECD Guideline 471 (Bacterial Reverse Mutation Assay), and T31-18: Chemical Substance Control Law of Japan.

The positive and negative controls demonstrated that the test system was valid. Microbial toxicity was observed at 5000 µg/plate in Salmonella typhimurium TA1535, TA1537, TA98, and TA100 with metabolic activation, however, no genetic mutation was observed in any strain with and without metabolic activation between 0 - 500 µg/plate. 2-Ethylbutyric acid was subsequently concluded not to be mutagenic at ≤5000 µg/plate.

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