Reaction mass of ethyl 2-ethyl-6,6-dimethylcyclohex-2-enecarboxylate and ethyl 2,3,6,6-tetramethylcyclohex-2-enecarboxylate

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:

1st August to 09 October 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

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:

Ethyl 2-ethyl-6,6-dimethylcyclohex-2-ene-1-carboxylate

EC Number:

261-020-5

EC Name:

Ethyl 2-ethyl-6,6-dimethylcyclohex-2-ene-1-carboxylate

Cas Number:

57934-97-1

Molecular formula:

C13H22O2

IUPAC Name:

ethyl 2-ethyl-6,6-dimethylcyclohex-2-ene-1-carboxylate

Constituent 2

Reference substance name:

Ethyl 2,3,6,6-tetramethylcyclohex-2-ene-1-carboxylate

EC Number:

278-776-7

EC Name:

Ethyl 2,3,6,6-tetramethylcyclohex-2-ene-1-carboxylate

Cas Number:

77851-07-1

Molecular formula:

C13H22O2

IUPAC Name:

ethyl 2,3,6,6-tetramethylcyclohex-2-ene-1-carboxylate

Specific details on test material used for the study:

Test material name: Givescone
Batch No.: 9000375280
Appearance: colourless to yellow pale liquid
Expiration date: March 10, 2002

Method

Species / strain

Species / strain / cell type:

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

Metabolic activation:

with and without

Metabolic activation system:

S-9 mix

Test concentrations with justification for top dose:

33; 100; 333; 1000; 2500; and 5000 microg/plate

Controls

Controls 1

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-phylene-diamine

Controls 2

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Results and discussion

Test results

Key result

Species / strain:

other: TA1535, TA1537, TA98, TA100 and TA102

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

Any other information on results incl. tables

Distinct toxic effects, evident as a reduction in the number of revertants, occured in the test groups with and without metabolic activation at the following concentrations:

	Experiment I (microg/plate)		Experiment II (microg/plate)
	without S9 mix	with S9 mix	without S9 mix	with S9 mix
TA1535	5000	5000	333, 2500 -5000	2500 - 5000
TA1537	100, 1000 - 5000	2500 - 5000	333 - 5000	1000 - 5000
TA98	/	/	333 - 5000	333 - 5000
TA100	333 - 5000	1000 - 5000	33 - 5000	333 - 5000
TA102	333 - 5000	/	100 -5000	333 - 5000

/ : no toxic effect received

The plates incubated with the test item showed irregular background growth at 1000 microg/plate and above with and without S9 mix in all strains.

No substancial increase in revertant colony numbers of any of the five tester strains was observed following treatment with Givescone at any dose level, neither in the presence nor in absence of metabolic activation (s9 mix). There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledge border of biological relevance.

Appropriate reference mutagens were used as postive controls and showed a disctinct increase of induced revertant colonies.

Applicant's summary and conclusion

Conclusions:

In conlusion it can be stated that during the described mutagenicity test an under the experimental conditions, the test item did not induce gene mutations by base pair of changes or framesshifts in the genome of strains used.
Therefore the Givescone is considered to be non mutagenic in the Salmonella Typhimurium reverse mutation assay.

Executive summary:

This study was perfomred to investigate the potential of Givescone to induce gene mutations according to the plate incorporation test (experiment I) and the pre-incubation test (experimemt II) using the Salmonella Typhimurium strains TA1535, TA1537, TA98, TA100 and TA102.

The assay was performed in two independant experiments both with and without liver microsomal activation. Each concentration, including the controls, was tested in triplicate.

The plates incubated with the test item showed irregular background growth at 1000 microg/plate and above with and without S9 mix in all strains.

No substancial increase in revertant colony numbers of any of the five tester strains was observed following treatment with Givescone at any dose level, neither in the presence nor in absence of metabolic activation (s9 mix). There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledge border of biological relevance.

Appropriate reference mutagens were used as postive controls and showed a disctinct increase of induced revertant colonies.

In conlusion it can be stated that during the described mutagenicity test an under the experimental conditions, the test item did not induce gene mutations by base pair of changes or framesshifts in the genome of strains used. Therefore the Givescone is considered to be non mutagenic in the Salmonella Typhimurium reverse mutation assay.