2-ethylbutyric acid

Genetic toxicity: in vitro

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 guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Test guideline 2

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

Test material information

Constituent 1

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 / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

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 results

Test results 1

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

Test results 2

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

Test results 3

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

Test results 4

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.