Sodium 1-(3,4-dihydro-6-methyl-2,4-dioxo-2H-pyran-3-ylidene)ethanolate

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:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Remarks:

Strain with AT base pair missing; not tested up to the maximum test concentration for soluble non-cytotoxic substances

Data source

Reference

Reference Type:

publication

Title:

Salmonella Mutagenicity Tests: III. Results From the Tesing of 255 Chemicals

Author:

Zeiger et al.

Year:

1987

Bibliographic source:

Environ Mutagen. 9:1-109

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

adopted 21 July 1997

Deviations:

yes

Remarks:

Strain with AT base pair missing; not tested up to maximum test concentration for soluble non-cytotoxic substances

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Sodium 1-(3,4-dihydro-6-methyl-2,4-dioxo-2H-pyran-3-ylidene)ethanolate

EC Number:

224-580-1

EC Name:

Sodium 1-(3,4-dihydro-6-methyl-2,4-dioxo-2H-pyran-3-ylidene)ethanolate

Cas Number:

4418-26-2

Molecular formula:

C8H7O4.Na

IUPAC Name:

sodium 1-(6-methyl-2,4-dioxo-2H-pyran-3(4H)-ylidene)ethanolate

Method

Target gene:

his operon

Species / strain

Species / strain / cell type:

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

Metabolic activation:

with and without

Metabolic activation system:

cofactor supplemented post-mitochondrial fraction (S9 mix), prepared from the livers of rats and hamsters treated with Aroclor 1254.

Test concentrations with justification for top dose:

33, 100, 333, 1000 and 1820 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: water

Controls

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive control substance:

other: -S9: sodium azide for TA100 and TA1535; 9-aminoacridine for TA1537; 4-nitro-o-phenylendiamine for TA98; +S9: 2 aminoanthracene (2.5 or 5 µg/plate) for all strains

Details on test system and experimental conditions:

METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 20 min
- Exposure duration: 48 h

NUMBER OF REPLICATIONS: Triplicates each in 2 independent experiments

DETERMINATION OF CYTOTOXICITY
- Method: relative total growth

Evaluation criteria:

A chemical was judged to be mutagenic or weakly mutagenic if it produced a reproducible, dose-related increase in his+ revertants over the corresponding solvent controls in replicate trials. A chemical was considered to be questionable if a reproducible increase of his+ revertants did not meet the criteria for either mutagenic or weakly mutagenic, or if only single doses produced an increase in his+ revertants in repeat trials.

Statistics:

Mean values and standard deviation were calculated.

Results and discussion

Test results

Test results 1

Key result

Species / strain:

other: TA 100, TAA 1535 and TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

-S9: ≥ 1000 µg/plate; + S9: ≥1820 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

RANGE-FINDING/SCREENING STUDIES: The test substance was tested inititally in a toxicity assay to determine the appropriate dose range (data not shown).

Any other information on results incl. tables

Table 1 Test Results

With or without S9-Mix	Test substance concentration	Mean number of revertant colonies per plate
	(μg/plate)	(average of 3 plates ± Standard deviation)
		Base-pair substitution type		Frameshift type
		TA 100	TA1535	TA98	TA1537
–	0	122 ± 24.2	5 ± 1.7	14 ± 2.5	4 ± 2.0
–	33	107 ± 2.9	6 ± 0.9	12 ± 0.7	5 ± 1.2
–	100	115 ± 14.1	6 ± 1.3	11 ± 0.3	5 ± 2.2
–	333	104 ± 5.5	3 ± 0.9	12 ± 0.6	5 ± 0.6
–	1000	100 ± 5.8	4 ± 1.2	8 ± 1.9	3 ± 0.9
–	1820	85 ± 9.5	4 ± 1.0	8 ± 0.9	4 ± 1.8
Positive controls, –S9	Name	SA	SA	4-NOP	9-AA
	Mean No. of colonies/plate (average of 3 ± SD)	571 ± 9.9	168 ± 5.9	407 ± 11.3	1088 ± 11.7
+	0	158 ± 5.0	6 ± 2.3	26 ± 4.5	6 ± 1.8
+	33	148 ± 12.2	4 ± 1.2	17 ± 4.2	6 ± 1.2
+	100	161 ± 14.7	5 ± 0.6	26 ± 1.0	5 ± 1.2
+	333	146 ± 12.7	7 ± 2.0	17 ± 1.5	4 ± 1.2
+	1000	134 ± 28.7	5 ± 0.3	17 ± 2.6	7 ± 1.7
+	1820	138 ± 23.6	6 ± 1.3	11 ± 2.0	5 ± 1.7
Positive controls, +S9 (rat)	Name	2AA	2AA	2AA	2AA
	Mean No. of colonies/plate (average of 3 ± SD)	3149 ± 19.0	80 ± 4.7	1621 ± 71.4	129 ± 9.2

Applicant's summary and conclusion

Conclusions:

Dehydroacetic acid, sodium salt DHA-Na (with or without metabolic activation) was not mutagenic in this Ames test.

Executive summary:

Dehydroacetic acid, sodium salt DHA-Na assessed in an Ames test at concentrations up to 1820µg/plate (with or without metabolic activation ) was shown to be not mutagenic.