4,7-dimethyloct-6-en-3-one

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

The study was conducted between 29 October 2003 and 11 November 2003.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2004

Report date:

2004

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

4,7-dimethyloct-6-en-3-one

EC Number:

219-845-3

EC Name:

4,7-dimethyloct-6-en-3-one

Cas Number:

2550-11-0

Molecular formula:

C10H18O

IUPAC Name:

4,7-dimethyloct-6-en-3-one

Test material form:

liquid

Specific details on test material used for the study:

Identity: Dimethyl Octenone
Batch No.: 9000523220
Aggregate State at Room Temperature: Liquid
Colour: Colorless to pale yellow
Purity: 96.5%

Method

Target gene:

Salmonella typhimurium: Histidine

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9 mix

Test concentrations with justification for top dose:

Test for Mutagenicity (Experiment 1 - Range-Finding Test) – Plate Incorporation Method: 3, 10, 33, 100, 333, 1000, 2500 and 5000 µg/plate.
Test for Mutagenicity (Experiment 2 - Main Test) – Pre-Incubation Method: 10, 33, 100, 333, 1000, 2500 and 5000 µg/plate.
Top dose represents standard maximum concentration.

Vehicle / solvent:

Ethanol

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

methylmethanesulfonate

other: 4-nitro-o-phenylene-diamine, (4-NOPD)

Remarks:

additional positive control: 2-aminoanthracene

Details on test system and experimental conditions:

For each strain and dose level (including the controls) three plates were used.
The following materials were mixed in a test tube and poured onto the selective agar plates:
- 100 μL Test solution at each dose level, solvent (negative control) or reference mutagen solution (positive control),
- 500 μL 89 mix (for test with metabolic activation) or 89 mix substitution buffer (for test without metabolic activation),
- 100 μL Bacteria suspension (cf. test system, pre-culture of the strains),
- 2000 μL Overlay agar
In the pre-incubation assay 100 μL test solution, 500 μL 89 mix I 89 mix substitution buffer and 100 μL bacterial suspension were mixed in a test tube and incubated at 37°C for 60 minutes. After pre-incubation 2.0 ml overlay agar (45° C) was added to each tube. The mixture was poured on minimal agar plates.
After solidification the plates were incubated upside down for at least 48 hours at 37° C in the dark.

Rationale for test conditions:

Strains TA 1537 and TA 98 are used to indicate frame shift mutations; Strains TA 1535, TA 102 and TA 100 are used to indicate base-pair substitution mutations.

Evaluation criteria:

A test item is considered as a mutagen if a biologically relevant increase in the number of revertants exceeding the threshold of twice (strains TA 98, TA 100, and TA 102) or thrice (strains TA 1535 and TA 1537) the colony count of the corresponding solvent control is observed.
A dose dependent increase is considered biologically relevant if the threshold is exceeded at more than one concentration.
An increase exceeding the threshold at only one concentration is judged as biologically relevant if reproduced in an independent second experiment.
A dose dependent increase in the number of revertant colonies below the threshold is regarded as an indication of a mutagenic potential if reproduced in an independent second experiment. However, whenever the colony counts remain within the historical range of negative and solvent controls such an increase is not considered biologically relevant.

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

Vehicle controls validity:

valid

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

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 4

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 5

Key result

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

During the described mutagenicity test and under its experimental conditions, the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used. Therefore, DIMETHYL OCTENONE is considered to be non-mutagenic.

Executive summary:

DIMETHYL OCTENONE was tested up to 5000 μg/plate and found to be negative with and without metabolic activation (S9 mix) in five strains of Salmonella typhimurium (TA 1535, TA 1537, TA 98, TA 100, and TA 102); DIMETHYL OCTENONE is therefore considered to be non-mutagenic.