6-methylhept-5-en-2-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

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes (incl. QA statement)

Remarks:

BASF Aktiengesellschaft Experimentelle Toxikogie und Ökologie Ludwigshafen

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

6-methylhept-5-en-2-one

EC Number:

203-816-7

EC Name:

6-methylhept-5-en-2-one

Cas Number:

110-93-0

Molecular formula:

C8H14O

IUPAC Name:

6-methylhept-5-en-2-one

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): 6-Methylhept-5-en-2-one (Methylheptenon)
- Test substance No.: 00/0874-1
- Physical state: colorless to yellowish liquid
- Analytical purity: 99.1%
- Purity test date: December 28, 2000
- Lot/batch No.: Continuous production
- Date of manufacture: November 14, 2000
- Storage condition of test material: refrigerator (N2 conditions)

Method

Target gene:

His, Trp gene

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:

20 - 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: Due to the limited solubility of the test substance in water, DMSO was selected as the vehicle, which had been demonstrated to be suitable in bacterial reverse mutation tests and for which historical control data are available.

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: TA1535, TA 100, TA 1537, TA 98: 2-aminoanthracene (2.5 µg/plate); E. coli WP2 uvrA: 2-aminoanthracene (60 µg/plate)

Remarks:

with metabolic activation

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

no

Positive control substance:

other: TA 1535, TA 100: N-methyI-N'-nitro-N-nitrosoguanidine (5 µg/plate); TA 98: 4-nitro-o-phenylendiamine (10 µg/plate); TA 1537: 9-aminoacridine (100 µg/plate); E. coli: 4-nitroquinoline-N-oxide (5 µg/plate)

Remarks:

without metabolic activation

Details on test system and experimental conditions:

METHOD OF APPLICATION:

1ST EXPERIMENT: in agar (plate incorporation)
(SPT)DURATION
- Exposure duration: 48 - 72 h, 37°C

2ND and 3RD EXPERIMENT: preincubation
(PIT)DURATION
- Preincubation period: 20 min, 37°C
- Exposure duration: 48 - 72 h, 37°C

DETERMINATION OF CYTOTOXICITY
- Method: decrease in the number of revertants, clearing or diminution of the background lawn (= reduced his- or trp- background growth), reduction in the titer

Evaluation criteria:

The test chemical is considered positive in this assay if the following criteria are met:- A dose-related and reproducible increase in the number of revertant colonies, i.e. about doubling of the spontaneous mutation rate in at least one tester strain either without S-9 mix or after adding a metabolizing system.A test substance is generally considered nonmutagenic in this test if:- The number of revertants for all tester strains were within the historical negative control range under all experimental conditions in two experiments carried out independently of each other.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other:

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

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

Additional information on results:

ADDITIONAL INFORMATION ON CYTOTOXICITY:
- A weak bacteriotoxic effect (slight decrease in the number of revertants and/or slight reduction in the titer) was occasionally abserved in the standard plate test depending on the strain and test conditions from about 2,500 µg/plate onward.
- In the preincubation assay bacteriotoxicity (reduced background growth, decrease in the number of revertants, reduction in the titer) was observed depending an the strain and test conditions from about 1,000 µg - 2,000 µg/plate onward.
- Precipitation: No test substance precipitation was found.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

An increase in the number of revertants was not observed both in the  standard plate test and in the preincubation test either without S-9 mix  or after the addition of a metabolizing system.
Thus, under the experimental conditions chosen here, it is concluded that 6-Methylhept-5-en-2-one is not a mutagenic agent in a bacterialreverse mutation test.

Applicant's summary and conclusion

Conclusions:

An increase in the number of revertants was not observed both in the standard plate test and in the preincubation test either without S-9 mix or after the addition of a metabolizing system. Thus, under the experimental conditions chosen here, it is concluded that 6-Methylhept-5-en-2-one (Methylheptenon) is not a mutagenic agent in a bacterial reverse mutation test and does not need to be classified for mutagenicity in accordance with the criteria outlined in Annex I of the CLP Regulation (1272/2008/EC).

Executive summary:

The substance 6-Methylhept-5-en-2-one (Methylheptenon) was tested for its mutagenic potential based on the ability to induce point mutations in selected loc of several bacterial strains, i.e. Salmonella typhimurium and Escherichia coli, in a reverse mutation assay. The strains tested were TA 1535, TA 100, TA 1537, TA 98 and E. coIi WP2 uvrA. These were tested in a standard plate test (SPT) and preincubation test (PIT) boths with and without metabolic activation (Aroclor-induced rat livers S-9 mix). Bacterial strains were exposed to 20 µg - 5,000 µg / plate (SPT), and 20 µg - 5,000 µg/plate (PIT), no precipitation of the test substance was found. A bacteriotoxic effect was observed under all test conditions, but no increase in the number of his+ or trp+ revertants was observed in the standard plate test or in the preincubation test either without S-9 mix or after the addition of a metabolizing system. Thus, according to the results of the present study, the test substance methylheptenon is not mutagenic in the Salmonella typhimurium/Escherichia coli reverse mutation assay under the experimental conditions chosen and does not need to be classified for mutagenicity in accordance with the criteria outlined in Annex I of the CLP Regulation (1272/2008/EC).