2-methylvaleraldehyde

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:

2007-04-02 to 2007-05-21

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented GLP study which meets basic scientific principles of OECD TG 471.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Qualifier:

no guideline followed

Deviations:

not applicable

Principles of method if other than guideline:

Liquid fluctuation test based on the method of Gee, P. et al. (1998), Mut. Res., 412, 115 - 130 (incubation in liquid medium in microwell plates using Ames II-compliant tester strains)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

2-methylvaleraldehyde

EC Number:

204-605-2

EC Name:

2-methylvaleraldehyde

Cas Number:

123-15-9

Molecular formula:

C6H12O

IUPAC Name:

2-methylpentanal

Details on test material:

- Name of test material: Methylpentanal Roh

Method

Target gene:

In the Salmonella typhimurium strains (TA 98, TA Mix 7001-7006) the amino acid histidine locus is the target gene, in which induced back mutations will transform the histidine auxotrophy (his-) to histidine prototrophy (his+). The Salmonella typhimurium histidine (his) reversion system measures his- => his+ reversions. The Salmonella typhimurium strains are constructed to differentiate between base pair (TA-Mix) and frameshift (TA 98) mutations.

Species / strain

Species / strain 1

Species / strain / cell type:

S. typhimurium TA 98

Additional strain / cell type characteristics:

other: rfa, uvrB

Species / strain 2

Species / strain / cell type:

S. typhimurium, other: TA Mix (TA 7001 - 7006)

Additional strain / cell type characteristics:

other: rfa, uvrB

Metabolic activation:

with and without

Metabolic activation system:

S9 mix (from liver homogenate of Aroclor 1254 treated rats)

Test concentrations with justification for top dose:

6, 30, 150, 750, 3750, 7500 µg/mL

Vehicle / solvent:

Vehicle used: DMSO

Controls

Untreated negative controls:

yes

Remarks:

sterility control/contaminants

Negative solvent / vehicle controls:

yes

Remarks:

vehicle control/spontaneous mutation rate

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-nitrofluorene (2-NF) and 4-nitroquinoline-N-oxide (4-NQO) were used in the experiments for direct mutagenicity and 2-aminoanthracene (2-AA) was used in the experiments with S9 mix.

Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation
Liquid exposure (liquid fluctuation test with and without S9 mix):
- without S9-mix: 240 μL Bacteria suspension and 10 μL test substance or positive control substance or vehicle
- exposure with S9-mix: 200 μL Bacteria suspension, 40 μL S9 mix (final concentration of 4.8% [v/v] S9 fraction), 10 μL test substance or positive control substance or vehicle
- Incubation period: 90 min at 37 °C under agitation
- Number of plates: 48 wells in triplicate plates per dose or per control (strains: TA 98, TA Mix; doses: 0, 6, 30, 150, 750, 3750 and 7500 μg/mL)
Prototrophic selection:
- Addition of Ames II Reversion Indicator medium (2.8 mL)
- Distribution in 50 µl Aliquots on Revertant Colony Selection Plate (RCSP)
- Incubation at 37°C for about 48 hours in the dark
- Number of positive wells (yellow) were counted


DETERMINATION OF CYTOTOXICITY: yes

Evaluation criteria:

Mutagenicity:
- Increase in the mean number of positive wells in dose groups versus the mean values of the concurrent negative control
- Increase in the mean of revertant wells in dose groups

Toxicity:
- Decrease in the number of positive wells
- Clearing or diminution of the background lawn

Solubility:
- Precipitation of the test substance

Criteria:
- Acceptance:
-Number of revertant wells in the negative controls was within the range of the historical negative control data
-Sterility controls revealed no indication of bacterial contamination
-Positive controls both with and without S9 mix induced a significant increase in the number of positive wells within the range
of the historical positive control data or above
- Assessment:
-Test chemical is considered positive if a dose-related and reproducible increase in the number of positive wells by a factor of about 2 or above in at least one tester strain either without S9 mix or after adding a metabolizing system
-Test substance is considered non-mutagenic if the number of revertant wells for all tester strains were within the historical negative control range

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium, other: TA Mix (TA 7001-7006)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: No test substance precipitation was found with and without metabolic activation.

COMPARISON WITH HISTORICAL CONTROL DATA: Yes
- Positive controls: Number of revertant wells were within the historical control range (TA98, TA Mix)
- Negative controls: Number of revertant wells were within the historical control range (TA98) or were adjacent to it (TA Mix)

ADDITIONAL INFORMATION: No bacteriotoxic effect was observed up to the highest applied test substance concentration.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.