(E)-3-methyl-4-(2,6,6-trimethylcyclohex-2-en-1-yl)but-3-en-2-one

Genetic toxicity: in vitro

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:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

test procedure in accordance with generally accepted scientific standards and described in sufficient detail

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1999

Report date:

1999

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

The preliminary toxicity study was not performed in duplicates and can not count as a full repeat experiment. Seeing the results obtained, it is not considered to have an effect on the outcome of the study.

Principles of method if other than guideline:

The test system was exposed to the test article via the plate incorporation methodology originally described by Ames et al. (1975) and updates by Maron and Ames (1983).

GLP compliance:

yes

Remarks:

Wagner III VO and Caruthers SM

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Ionone, methyl-

EC Number:

215-635-0

EC Name:

Ionone, methyl-

Cas Number:

1335-46-2

Molecular formula:

C14H22O

IUPAC Name:

Ionone, methyl

Specific details on test material used for the study:

Lot No: 9709000929
Purity: 98%

Method

Target gene:

his

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:

Aroclor-1254 induced rat liver S9 mix

Test concentrations with justification for top dose:

in the preliminary mutagenicity test: <= 5000 µg/plate methyl ionone
in the mutagenicity assay: 25 - 5000 µg/plate methyl ionone

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Controls

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

not specified

Positive control substance:

not specified

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

Results and discussion

Test results

Test results 1

Key result

Species / strain:

other: S. typhimurium TA98, TA100, TA1535, TA1537 and E.coli WP2

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at the highest doses

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Test results 3

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

≥1800μg per plate +/- S9

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Test results 4

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Test results 5

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

≥1800μg per plate

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: no

Applicant's summary and conclusion

Conclusions:

A bacterial reverse mutation assay was conducted on Salmonella typhimurium strains TA98, TA100, TA1535 and TA1537, and Escherichia coli strain WP2uvrA in the presence and absence of S9 activation. Methyl ionone in dimethyl sulfoxide was tested at 25, 75, 200, 600, 1800, and 5000 ug/plate, and no positive response was observed. Methyl ionone was concluded to be negative in the bacterial reverse mutation assay.

Executive summary:

The test article, methyl ionone, was tested in the bacterial reverse mutation assay using S. typhimurium tester strains TA98, TA100, TA1535, TA1537 and E. coli tester strain WP2uvrA in the presence and absence of Aroclor-induced rat liver S9. The assay was performed in two phases, using the plate incorporation method. The first phase, the preliminary toxicity assay, was used to establish the dose range for the mutagenicitiy assay. The second phase, the mutagenicity assay, was used to evaluate the mutagenic potential of the test article. Dimethyl sulfoxide was selected as the solvent of choice based on solubility of the test article and compatibility with the target cells. The test article was soluble in dimethyl sulfoxide at a maximum concentration of approx. 500 mg/mL. In the preliminary assay, the maximum dose tested was 5000 ug/plate; this dose was achieved using a concentration of 100 mg/mL and a 50 uL plating aliquot. No precipitate was observed. Toxicity was observed at greater than or equal to 6667 ug/plate and at 5000 ug/plate with tester strain TA100 in the absence and presence of S9 activation, respectively. Toxicity was observed at greater than or 1000 ug/plate and at greater than or equal to 3333 ug/plate in the absence of S9 activation with tester strains TA1535 and TA1537, resp. Based on the findings of the toxicity assay, the maximum dose plated in the mutagenicity assay was 5000 ug/plate. In the mutagenicity assay, no positive response was observed. Under the conditions of this study, test article, methyl ionone, was concluded to be negative in the Bacterial Reverse Mutation Assay.