2-methylpent-2-enal

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1996-10-23 to 1998-10-13

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP and guideline study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1998

Report date:

1998

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

May 1983/Revised Draft, March 1996

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 472 (Genetic Toxicology: Escherichia coli, Reverse Mutation Assay)

Version / remarks:

May 1983/Revised Draft, March 1996

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)

Version / remarks:

December 1992

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

2-methylpent-2-enal

EC Number:

210-789-5

EC Name:

2-methylpent-2-enal

Cas Number:

623-36-9

Molecular formula:

C6H10O

IUPAC Name:

2-methylpent-2-enal

Method

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 S-9 mix

Test concentrations with justification for top dose:

1st and 2nd experiment: 0; 20; 100; 500; 2500; 5000 µg/plate (all strains)
3rd experiment: 0; 1000; 2000; 3000; 4000; 5000 µg/plate (TA 100 only)

Vehicle / solvent:

DMSO

Controls

Controls 1

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene (2-AA)

Remarks:

S. typhimurium TA 1535, TA 100, TA 1537, TA 98 and E. coli WP2 uvrA with S-9 mix

Controls 2

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: N-methyl-N' -nitro-N-nitrosoguanidine (MNNG)

Remarks:

S. typhimurium TA 1535, TA 100 without S-9 mix

Controls 3

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylendiamine (NOPD)

Remarks:

S. typhimurium TA98 without S-9 mix

Controls 4

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

S. typhimurium TA1537 without S-9 mix

Controls 5

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

N-ethyl-N-nitro-N-nitrosoguanidine

Remarks:

E. coli WP2 uvrA without S-9 mix

Details on test system and experimental conditions:

METHOD OF APPLICATION: standard plate test
DURATION
- Exposure duration: 48 - 72 h at 37 °C
NUMBER OF REPLICATIONS: 3 per dose

METHOD OF APPLICATION: liquid suspension assay (pre-incubation test)
DURATION
- Preincubation period: 90 min at 37 °C
- Exposure duration: 48 - 72 h at 37 °C
NUMBER OF REPLICATIONS: 3 per dose

DETERMINATION OF CYTOTOXICITY:
- Method: relative total growth, background lawn

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 numbber 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.

Statistics:

NA

Results and discussion

Test results

Test results 1

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:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 5000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 4

Species / strain:

other: TA 1535, TA 1537, TA 98, E. coli WP2 uvrA

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 5000 µg/plate using the strains TA 1537, TA 98, and E. coli WP2 uvrA

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

Stability: No substance precipitation was found.

Standard plate test:
No increase in the number of his+ or trp+ revertants was found in the Standard plate test in all tested strains with and without S-9 mix.

Liquid suspension assay:
Tests without S-9 mix:
TA 100: Mutagenicity was observed from abaut 500 µg - 1000 µg/plate (factor 1.4 - 1.8) onward with a maximum increase in the number of his revertants by a factor of 3.4 - 3.7 at 2500 µg - 3000 µg/plate.
TA 1535, TA 1537, TA 98, E. coli WP2 uvrA: No increase in the number of his+ and trp+ revertants.
Tests with S-9 mix:
TA 100: Positive reaction from abaut 2000 µg - 2500 µg/plate (factor 1.4 - 1.8) onward with an increase in the number of mutant colonies by a factor of 1.6 - 1.8 at 2500 µg - 5000 µg/plate (1st liquid suspension assay) or of 3.1 at 5000 µg/plate (2nd liquid suspension assay)

Remarks on result:

other: other: standard plate test

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
positive

Under the experimental conditions chosen, it is concluded that 2-Methylpenten-2-al-1 is a mutagenic agent in a bacterial reverse mutation test in vitro.

Executive summary:

The substance 2-Methylpenten-2-al-1 was tested for mutagenicity in the Salmonella typhimurium/ Escherichia coli reverse mutation assay both in the standard plate test and in the liquid suspension assay (= preincubation method) with and without the addition of a metabolizing system obtained from rat liver (S-9 mix) using the Salmonella strains TA 1535, TA 100, TA 1537, TA 98 and Escherichia coli WP2 uvrA.

In the standard plate test, no increase in the number of revertants were found in all tested strains with and without S-9 mix.

In the liquid suspension assay in the tests without S-9 mix, at the tested strain TA100, mutagenicity was observed from about 500 - 1000 µg/plate (factor 1.4 - 1.8) onward with a maximum increase in the number of his+ revertants by a factor of 3.4 - 3.7 at 2500 - 3000 µg/plate. In the strains TA1535, TA1537, TA 98 and E. coli WP2 uvrA, no increase in the number of his+ and trp+ revertants was observed.

In the liquid suspension assay in the tests with S-9 mix, at the tested strain TA100, positive reaction from about 2000 - 2500 µg/plate (factor 1.4 - 1.8) onward with an increase in the number of mutant colonies by a factor of 1.6 - 1.8 at 2500 - 5000 µg/plate (1st liquid suspension assay) or of 3.1 at 5000 µg/plate (2nd liquid suspension assay). In the strains TA1535, TA1537, TA 98 and E. coli WP2 uvrA, no increase in the number of his+ and trp+ revertants was observed.

Thus, under the experimental conditions chosen here, it is concluded that 2-Methylpenten-2-al-1 rein is a mutagenic agent in a bacterial reverse mutation test in vitro.