Phenethyl pivalate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

In a bacterial reverse mutation assay, conducted similarly to OECD 471 Guideline and to GLP, , Phenethyl pivalate was not considered as mutagenic in S. typhimurium (TA1535, TA1537, TA1538, TA98 and TA100) strains with or without metabolic activation. The QSAR on TA102 in the absence and presence of S(-mix are both predicted to be negative with strong confidence.

Link to relevant study records

Reference

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:

22 May 1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study conducted similarly to OECD 471 Guideline with deviations: strains E. coli WP2 or S. typhimurium TA102 not used; purity of test item, evaluation and acceptance criteria and individual plate counts not reported

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

strains E. coli WP2 or S. typhimurium TA102 not used; purity of test item, evaluation and acceptance criteria and individual plate counts not reported

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Target gene:

None

Species / strain / cell type:

S. typhimurium, other: TA 1535, TA 1537, TA 1538, TA 98 and TA 100

Details on mammalian cell type (if applicable):

Not applicable

Additional strain / cell type characteristics:

other: examined for the number of spontaneous revertants, histidine requirement and sensitivity to ampicillin, crystal violet and UV radiation.

Metabolic activation:

with and without

Metabolic activation system:

10 % S9 mix; S9 fraction prepared from liver homogenates of male Wistar rats intraperitoneally induced with Aroclor 1254 (500 mg/kg bw) as a 20 % (w/v) dilution in soya bean oil

Test concentrations with justification for top dose:

Preliminary toxicity test with strain TA 98:
- Approximately 0.009, 0.09, 0.9 and 9 mg/plate

Mutagenicity test:
- 3.7, 11.1, 33.3, 100 and 300 µg/plate, with and without S9 mix in TA 1535, TA 1537, TA 1538, TA 98 and TA 100 strains

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Methanol
- Test substance preparation: Appropriate test solutions in methanol (0, 37, 111.1, 333.3, 1000 and 3000 µg/mL) were prepared immediately before use.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

methanol

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: sodium azide (0.5 µg/plate (in 0.1 mL water)) for strains TA 1535 and TA 100 ; hycanthone methanesulphonate (12.5 µg/plate (in 0.1 mL water)) for strains TA 1537, TA 1538 and TA 98

Remarks:

without S-9 mix

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

methanol

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene (0.5 µg/plate (in 0.1 mL DMSO) for all strains

Remarks:

with S-9 mix

Details on test system and experimental conditions:

SOURCE OF TEST SYSTEM: - All Salmonella typhimurium strains received from Dr. B.N. Ames, Berkeley, California, U.S.A.

METHOD OF APPLICATION: In agar (plate incorporation)

DURATION
- Incubation period: Plates were incubated at 37 °C for three days

NUMBER OF REPLICATIONS:
- 3 plates/dose for treatment, vehicle and positive controls

DETERMINATION OF CYTOTOXICITY
- Method: Toxicity was determined based on background lawn of bacterial growth.

OTHER:
- Colony counting: After incubation, the colonies (revertants which are histidine independent) were counted and the background lawn of bacterial growth was examined microscopically.

Evaluation criteria:

None

Statistics:

None

Species / strain:

S. typhimurium, other: TA 1535, TA 1537, TA 1538, 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 applicable

Positive controls validity:

valid

Additional information on results:

CYTOTOXICITY:
- In a preliminary toxicity test, 0.9 mg/plate was still toxic whereas 0.09 mg/plate did not show a growth-inhibiting effect. Therefore 0.3 mg/plate was chosen as the highest dosage level for the mutagenicity study.

MUTAGENICITY TEST:
- The toxicity of the test substance for the bacteria appeared not to prevent adequate mutagenicity testing: at the higher dosage levels Phenethyl pivalate was clearly toxic for the bacteria, but at lower levels the background lawn of bacterial growth in control and test plates was comparable.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

See the attached document for information on tables of results

Conclusions:

Interpretation of results (migrated information):
negative with metabolic activation
negative without metabolic activation

Under the test conditions, Phenethyl pivalate is not considered as mutagenic in S. typhimurium (TA1535, TA1537, TA1538, TA98 and TA100) strains.

Executive summary:

In a reverse gene mutation assay in bacteria, performed similarly to the OECD Guideline 471 and in compliance with GLP, strains of Salmonella typhimurium (TA1535, TA1537, TA1538, TA98 and TA100) were exposed to Phenethyl pivalate at the following concentrations:

Preliminary toxicity test with strain TA 98:

- Approximately 0.009, 0.09, 0.9 and 9 mg/plate

Mutagenicity test:

- 3.7, 11.1, 33.3, 100 and 300 µg/plate, with and without S9 mix in TA 1535, TA 1537, TA 1538, TA 98 and TA 100 strains

Metabolic activation system used in this test 10 % S9 mix; S9 fraction prepared from liver homogenates of male Wistar rats intraperitoneally induced with Aroclor 1254 (500 mg/kg bw) as a 20 % (w/v) dilution in soya bean oil. Vehicle and positive control groups were also included in mutagenicity tests.

In a preliminary toxicity test, 0.9 mg/plate was still toxic whereas 0.09 mg/plate did not show a growth- inhibiting effect. Incorporation of the test product with the bacteria at levels up to 300 µg/plate did not increase the numbers of his+ revertants with any of the five tester strains, either in the presence or in the absence of S-9 mix. The toxicity of the test substance for the bacteria appeared not to prevent adequate mutagenicity testing: at the higher dosage levels Phenethyl pivalate was clearly toxic for the bacteria, but at lower levels the background lawn of bacterial growth in control and test plates was comparable. The positive and vehicle controls induced the appropriate responses in the corresponding strains indicating the validity of the study.

 

Under the test conditions, Phenethyl pivalate is not considered as mutagenic in this bacterial system.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

Justification for selection of genetic toxicity endpoint
GLP study conducted similarly to OECD 471 Guideline with deviations

Justification for classification or non-classification

Based on negative results in a reliable reverse mutation assay in five strains of S. typhimurium, classification under the EU DSD or CLP regulations is not required.