3,7-dimethylocta-1,3,6-triene

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

A study equivalent to OECD TG 471: Negative

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 Oct 2004 to 02 Nov 2004

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Target gene:

- S. typhimurium: Histidine gene
- Escherichia coli: Tryptophan gene

Species / strain / cell type:

S. typhimurium, other: TA 97a

Species / strain / cell type:

S. typhimurium TA 98

Species / strain / cell type:

S. typhimurium TA 100

Species / strain / cell type:

S. typhimurium TA 1535

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

Arochlor induced rat S9

Test concentrations with justification for top dose:

- Range finding assay
Test substance was tested in triplicate at six dose levels (50, 15.8, 5, 1.58, 0.5 and 0.16 µL/mL) along with a vehicle control. There values are equivalent to 5.0, 1.58, 0.5, 0.16, 0.05 and 0.016 µL/ plate.
In addition to a substantial decrease in the colony numbers, massive reductions in the background lawn were noted at doses 1-4. The toxicity level remained high at dose 5 but was reduced to moderate levels at dose 6. These doses were chosen based on maximizing the applied dose which minimizing the interference related to toxicity.

- Definitive assay
For the definitive assay, three doses were chosen: 0.016, 0.005 and 0.0016 µL/ plate.

Vehicle / solvent:

100% ethanol

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: See section 'any other information on materials and methods'

Details on test system and experimental conditions:

METHOD OF APPLICATION:
In agar (plate incorporation)

DURATION
Exposure duration: 48-72 hours

NUMBER OF REPLICATIONS: triplicates

OTHER:
All plates were counted using an automatic image analysis system. Negative control and test article treated plates were also examined for the presence of a bacterial lawn.

Evaluation criteria:

An induced positive result for any strain would be demonstrated by at least a two-fold increase in the number of revertant colonies per plate over the negative control values.

Key result

Species / strain:

S. typhimurium, other: TA 97a

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

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

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

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

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Key result

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

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:

not examined

Positive controls validity:

valid

Additional information on results:

RANGE-FINDING/SCREENING STUDIES:
Doses 5.0, 1.58, 0.5, 0.16 µg/ plate induced a complete reduction in the background lawn in both activation conditions. The spontaneous colony counts were also lower than normal. The lawn was also substantially affected at the 0.05 µL/ plate dose. No relevant effects were noted in the average colony counts at this dose. Strain TA 100 met all of the characteristic genotypic qualifications: it retained its characteristic sensitivity to positive controls, was resistant to Ampicillin, sensitive to crystal violet, tetracycline and UV irritation.

Genotypic characterization of the test strains.

Each strain was confirmed for genotypic markers and acceptable spontaneous reversion rates to ensure the strains maintained the characteristics which make them sensitive to mutagenic activity. Strain TA 102, which is is known to be resistant to tetracycline and UV, was used as genotypic control and appropriately grew in this genotypic test.

Conclusions:

The substance is not mutagenic in the Salmonella Typhimurium and Escherichia Coli reverse mutation assay performed equivalent to OECD 471.

Executive summary:

The mutagenic activity of the test substance was evaluated in a study equivalent to OECDTG 471 (1997) and according to GLP principles. A plate incorporation assay was performed in the absence and presence of Arochlor induced rat S9 mix. The dose levels were selected based on observed cytotoxicity in a dose range finding studies. The test substance was considered to be toxic in concentrations above 0.016 µg/plate. Solvent controls and positive controls were included. The substance did not induce a significant dose related increase in the number of revertant (His+) colonies in each of the four S. typhimurium tester strains (TA 97a, TA 98, TA 100 and TA 1535) and (Trp+) colonies in the E. coli tester strain (WP2 uvr A), both in the absence and presence of metabolic activation. Based on the results of this study it is concluded that the test substance is not mutagenic in the Salmonella typhimurium reverse mutation assay and Escherichia coli reverse mutation assay.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

The mutagenic activity of the test substance was evaluated in a study equivalent to OECDTG 471 (1997) and according to GLP principles. A plate incorporation assay was performed in the absence and presence of Arochlor induced rat S9 mix. The dose levels were selected based on observed cytotoxicity in a dose range finding studies. The test substance was considered to be toxic in concentrations above 0.016 µg/plate. Solvent controls and positive controls were included. The substance did not induce a significant dose related increase in the number of revertant (His+) colonies in each of the four S. typhimurium tester strains (TA 97a, TA 98, TA 100 and TA 1535) and (Trp+) colonies in the E. coli tester strain (WP2 uvr A), both in the absence and presence of metabolic activation. Based on the results of this study it is concluded that the test substance is not mutagenic in the Salmonella typhimurium reverse mutation assay and Escherichia coli reverse mutation assay.

Justification for classification or non-classification

Based on the negative results of the Ames test, the test substance does not need to be classified for genotoxicity in vitro according to EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008 and its updates.