Dimethyl (p-methoxybenzylidene)malonate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Dimethyl (p-methoxybenzylidene)malonate

EC Number:

231-185-8

EC Name:

Dimethyl (p-methoxybenzylidene)malonate

Cas Number:

7443-25-6

Molecular formula:

C13H14O5

IUPAC Name:

1,3-dimethyl 2-[(4-methoxyphenyl)methylidene]propanedioate

Test material form:

solid

Specific details on test material used for the study:

On the day of the experiment, the test item was dissolved in DMSO (MERCK, D-64293 Darmstadt; purity > 99 %). The solvent was chosen because of its solubility properties and its relative non-toxicity to the bacteria.
No precipitation of the test item occurred up to the highest investigated dose.

Method

Target gene:

Salmonella typhimurium; STRAINS TA 1535, TA1537, TA 98, TA 100, and E. coli WP2 uvrA

Test concentrations with justification for top dose:

To establish a dose response effect 6 dose levels with adequately spaced intervals were tested: 33, 100, 333, 1000, 2500 and 5000 µg/plate. The maximum dose level was 5000 µg/plate.

Vehicle / solvent:

DMSO

Details on test system and experimental conditions:

Negative controls:
Concurrent untreated and solvent controls were performed.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

S. typhimurium TA 1535

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

Test results 2

Key result

Species / strain:

S. typhimurium TA 1537

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

Test results 3

Key result

Species / strain:

S. typhimurium TA 98

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

Test results 4

Key result

Species / strain:

S. typhimurium 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

Test results 5

Key result

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:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

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, the test item is considered to be non-mutagenic in this Salmonella typhimurium and Escherichia coli reverse mutation assay.

Executive summary:

This study was performed to investigate the potential of Sanduvor PR-25 to induce gene mutations according to the plate incorporation test (experiment I) and the pre-incubation 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: 33; 100; 333; 1000; 2500; and 5000 µg/plate. The plates incubated with the test item showed normal background growth up to 5000 µg/plate with and without metabolic activation in both independent experiments. Distinct toxic effects, evident as a reduction in the number of revertants, occurred in the Salmonella strains with and without metabolic activation at higher concentrations.

No substantial increase in revertant colony numbers of any of the five tester strains was observed following treatment with the test item 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.