Reaction mass of (2R,5R)-2-isopropyl-5-methylcyclohexanone and (2S,5R)-2-isopropyl-5-methylcyclohexanone

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

other: component of reaction mass

Adequacy of study:

key study

Study period:

from 2012-05-23 to 2012-09-14

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study according to OECD TG 471

Data source

Reference

Reference Type:

secondary source

Title:

No information

Author:

ECHA disseminated dossier

Year:

2012

Bibliographic source:

Dossier CAS 14073-97-3

Report date:

2012

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:

Automatically generated during migration to IUCLID 6, no data available

IUPAC Name:

Automatically generated during migration to IUCLID 6, no data available

Details on test material:

- Name of test material (as cited in study report): Menthone-L/Isomenthone-D

Method

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

S9-mix

Test concentrations with justification for top dose:

Experiment I (pre-experiment, plate incorporation test): 3, 10, 33, 100, 333, 1000, 2500 and 5000 µg/plate
Experiment II (pre-incubation test):
TA1535, TA1537, TA100: 1, 3, 10, 33, 100, 333, 1000, 2500 and 5000 µg/plate
TA98, WP2 uvrA: 3, 10, 33, 100, 333, 1000, 2500 and 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: The solvent was chosen because of its solubility properties and its relative non-toxicity to the bacteria

Controls

Untreated negative controls:

yes

Remarks:

concurrent untreated

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

Positive controls:

yes

Positive control substance:

other: 1342 4-nitro-phenylene-diamine, 2-aminoanthracene

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation); preincubation

DURATION
- Preincubation period: 60 min
- Exposure duration: 48 h

NUMBER OF CELLS EVALUATED: 10^8-10^9 cells/mL

DETERMINATION OF CYTOTOXICITY
- Method: a reduction in the number of spontaneous revertants or a clearing of the bacterial background lawn.

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 WP2 uvrA) 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

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1000-5000 µg/plate Experiment I, 333-2500 µg/plate Experiment II

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1000-5000 µg/plate Experiment I, 333-2500 µg/plate Experiment II

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1000-5000 µg/plate Experiment I, 333-5000 µg/plate Experiment II

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

1000-5000 µg/plate Experiment I, 100-2500 µg/plate Experiment II

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 5

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

2500-5000 µg/plate Experiment I, 333-5000 µg/plate Experiment II (-S9-mix), 1000-5000 µg/plate Experiment II (+S9-mix)

Any other information on results incl. tables

The plates incubated with the test item showed reduced background growth at the following concentrations (µg/plate):

Strain	Experiment I		Experiment II
	without S9 mix	with S9 mix	without S9 mix	with S9 mix
TA1535	1000 – 5000	1000 – 5000	333 – 2500	333 – 2500
TA1537	1000 – 5000	1000 – 5000	333 – 2500	333 – 2500
TA98	1000 – 5000	1000 – 5000	333 – 5000	333 – 5000
TA100	1000 – 5000	1000 – 5000	333 – 2500	333 – 2500
WP2 uvrA	2500, 5000	2500, 5000	333 – 5000	1000 - 5000

 

Toxic effects, evident as a reduction in the number of revertants (below the indication factor of 0.5), occurred in the test groups at the following concentrations (µg/plate):

 

Strain	Experiment I		Experiment II
	without S9 mix	with S9 mix	without S9 mix	with S9 mix
TA1535	1000 – 5000	2500, 5000	1000, 2500	1000, 2500
TA1537	1000 – 5000	1000 – 5000	333 – 2500	1000, 2500
TA98	5000	5000	1000 – 5000	1000 – 5000
TA100	2500, 5000	1000 – 5000	1000, 2500	100, 2500
WP2 uvrA	/	2500, 5000	1000 – 5000	1000 - 5000

/ no toxic effects observed

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

It can be stated that during the described mutagenicity test and under the experimental conditions reported, the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used.

Executive summary:

This study was performed to investigate the potential of Menthone-L/Isomenthone-D to induce gene mutations in the plate incorporation test (experiment I) and the preincubation test (experiment II) using the Salmonella typhimurium strains TA 1535, TA 1537, TA 98, and TA 100, and the Escherichia coli strain WP2 uvrA.

The assay was performed in two independent experiments both with and without liver microsomal activation. Each concentration, including the controls, was tested in triplicate. The test item was tested at the following concentrations:

Pre-Experiment/Experiment I, all strains: 3; 10; 33; 100; 333; 1000; 2500; and 5000 µg/plate

Experiment II, TA 1535, TA 1537 TA 100: 1; 3; 10; 33; 100; 333; 1000; and 2500 µg/plate

TA 98; WP2 uvrA: 3; 10; 33; 100; 333; 1000; 2500; and 5000 µg/plate

At higher concentrations the background growth was reduced with and without metabolic activation in all strains in both independent experiments. Toxic effects, evident as a reduction in the number of revertants (below the indication factor of 0.5), occurred in the test groups with and without metabolic activation in all strains in both independent experiments.

No substantial increase in revertant colony numbers of any of the five tester strains was observed following treatment with Menthone-L/Isomenthone-D at any dose level, neither in the presence nor absence of metabolic activation (S9 mix). There was also no

tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledged border of biological relevance. Appropriate reference mutagens were used as positive controls and showed a distinct increase of induced revertant colonies.

In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used.Therefore, Menthone-L/Isomenthone-D is considered to be non-mutagenic in this Salmonella typhimurium and Escherichia coli reverse mutation assay.