2-Propenal, 3-(5,5-dimethyl-1,3-dioxan-2-yl)-2-methyl-, (2E)-

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

2-Propenal, 3-(5,5-dimethyl-1,3-dioxan-2-yl)-2-methyl-: a stereoisomer of 2-Propenal, 3-(5,5-dimethyl-1,3-dioxan-2-yl)-2-methyl-, (E)- is not considered to be mutagenic in a bacterial reverse mutation study (OECD 471).

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP compliant guideline study, available as unpublished report, restriction in design (no E.coli WP2 or S.typhimurium TA 102 used and only one positive control used to test efficacy of the S9-mix), but adequate for assessment

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

, no E.coli WP2 or S.typhimurium TA 102 used and only one positive control used to test efficacy of the S9-mix.

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Target gene:

His-locus

Species / strain / cell type:

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

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

Aroclor 1254-induced rat liver S9 mix

Test concentrations with justification for top dose:

- Experiment 1: 20, 100, 500, 2500, 5000 µg/plate
- Experiment 2: 15, 50, 150, 500, 1500 µg/plate

Vehicle / solvent:

- Vehicle used: DMSO

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Remarks:

10 µg/plate

Positive control substance:

other: 2-aminoanthracene

Remarks:

all strains with metabolic activation

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Remarks:

5 µg/plate

Positive control substance:

other: N-methyl-N'-nitro-N-nitrosoguanidine

Remarks:

TA 100, TA 1535; without metabolic activation

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Remarks:

10 µg/plate

Positive control substance:

other: 4-nitro-o-phenylendiamine

Remarks:

TA 98; without metabolic activation

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Remarks:

100 µg/plate

Positive control substance:

9-aminoacridine

Remarks:

TA 1537; without metabolic activation

Details on test system and experimental conditions:

EXPERIMENT 1
- METHOD OF APPLICATION: in agar (plate incorporation)
- DURATION: Exposure duration: 48 h
- NUMBER OF REPLICATIONS: 3 test plates per dose or per control
- DETERMINATION OF CYTOTOXICITY: Method: reduced his- background growth, decrease in the number of his + revertants

EXPERIMENT 2
- METHOD OF APPLICATION: preincubation
- DURATION: Preincubation period: 20 min; Exposure duration: 48 h
- NUMBER OF REPLICATIONS: 3 test plates per dose or per control
- DETERMINATION OF CYTOTOXICITY: Method: reduced his- background growth, decrease in the number of his + revertants

Evaluation criteria:

In general, a substance to be characterized as positive in the Ames test has to fulfill the following requirements:
- doubling of the spontaneous mutation rate (control)
- dose-response relationship
- reproducibility

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:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Solvent solubility: Complete solubility of the test substance in DMSO

ADDITIONAL INFORMATION ON CYTOTOXICITY:
A bacteriotoxic effect (reduced his- background growth, decrease in the number of his+ revertants) was observed depending on the strain and test conditions in the standard plate test at dose ≥ 2500 µg/plate and in the preincubation test at 1500 µg/plate.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative

It is concluded that there is no evidence of induction of gene mutations by the test substance in the absence and presence of a metabolic activation system in the four S. typhimurium strains used in this study.

Executive summary:

In an OECD 471 guideline study, the substance was tested for its mutagenic potential based on the ability to induce point mutation in selected loci of several strains of Salmonella typhimurium (TA 1535, TA 100, TA 1537, TA98) in a reverse mutation assay. Bacteria were exposed to 20 -5000 µg test substance/plate in a standard plate test and in a preincubation test in the presence and absence of a metabolizing system (rat liver S-9 mix). A bacteriotoxic effect was observed depending on the strain and test conditions at doses ≥2500 µg/plate (standard plate test) and at 1500 µg/plate (preincubation test). An increase in the number of his+ revertants was not observed in the standard plate test or in the preincubation test either without S9 mix or after the addition of a metabolizing system. It was therefore concluded that the test substance is not mutagenic under these experimental conditions.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

No studies on the genotoxic properties of 2-Propenal, 3-(5,5-dimethyl-1,3-dioxan-2-yl)-2-methyl-, (E)- were available. However, Article 13 of REACH states that, in case no appropriate animal studies are available for assessment, information should be generated whenever possible by means other than vertebrate animal tests, i.e. applying alternative methods such as in vitro tests, QSARs, grouping and read-across. A bacterial reverse mutation assay with 2-Propenal, 3-(5,5-dimethyl-1,3-dioxan-2-yl)-2-methyl-(MBDA) a stereoisomer of 2-Propenal, 3-(5,5-dimethyl-1,3-dioxan-2-yl)-2-methyl-, (E)- is available.

In an OECD 471 guideline study, MBDA was tested for its mutagenic potential based on the ability to induce point mutation in selected loci of several strains of Salmonella typhimurium (TA 1535, TA 100, TA 1537, TA98) in a reverse mutation assay. Bacteria were exposed to 20 -5000 µg test substance/plate in a standard plate test and in a preincubation test in the presence and absence of a metabolizing system (rat liver S-9 mix) (BASF 1989). A bacteriotoxic effect was observed depending on the strain and test conditions at doses ≥2500 µg/plate (standard plate test) and at 1500 µg/plate (preincubation test). An increase in the number of his+ revertants was not observed in the standard plate test or in the preincubation test either without S9 mix or after the addition of a metabolizing system. It was therefore concluded that the test substance is not mutagenic under these experimental conditions.

Justification for selection of genetic toxicity endpoint
One bacterial reverse mutation study with a steroisomer of 2-Propenal, 3-(5,5-dimethyl-1,3-dioxan-2-yl)-2-methyl-, (E)- is available. This study is adequate for covering this endpoint.

Justification for classification or non-classification

2-Propenal, 3-(5,5-dimethyl-1,3-dioxan-2-yl)-2-methyl-, a steroisomer of 2-Propenal, 3-(5,5-dimethyl-1,3-dioxan-2-yl)-2-methyl-, (E)- is non-mutagenic in a bacterial reverse mutation assay. It is expected that 2-Propenal, 3-(5,5-dimethyl-1,3-dioxan-2-yl)-2-methyl-, (2E)- will also be non-mutagenic in the strains tested. Based on this classification for genetic toxicity is not warranted in accordance with EU Directive 67/548 (DSD) and EU Classification, Labeling and Packaging of Substances and Mixtures (CLP) Regulation No. 1272/2008.