2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one

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:

2002

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Report date:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one

EC Number:

400-600-6

EC Name:

2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one

Cas Number:

71868-10-5

Molecular formula:

C15 H21 N O2 S

IUPAC Name:

2-methyl-1-[4-(methylsulfanyl)phenyl]-2-(morpholin-4-yl)propan-1-one

Method

Target gene:

His: Salmonella
Trp: E. coli

Species / strain

Species / strain / cell type:

other: Salmonella typhimurium strains TA 1535, TA 1537, TA 98, and TA 100, and the Escherichia coli strain WP2 uvrA.

Metabolic activation:

with and without

Metabolic activation system:

Phenobarbital/beta-Naphthoflavone induced rat liver S9-mix

Test concentrations with justification for top dose:

33; 100; 333; 1000; 2500; and 5000 µg/plate

Vehicle / solvent:

Dimethylsulfoxide (DMSO)

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: see: "Details on test system and conditions"

Details on test system and experimental conditions:

DOSE SELECTION
In the pre-experiment the concentration range of the test item was 3 - 5000 µg/plate. The pre-experiment is reported as experiment I since no relevant toxic effects were observed and 5000 µg/plate were chosen as maximal concentration.

The test item was assessed for its potential to induce gene mutations according to the plate incorporation test (experiment I) and the pre-incubation
test (experiment II). The assay was performed in two independent experiments both with and without liver microsomal activation.

DURATION
- Preincubation period: 60 minutes
- Exposure duration: 72 hours

NUMBER OF REPLICATIONS: 3

-POSITIVE CONTROLS:
Without metabolic activation

Strains: TA 1535, TA 100
Name: sodium azide, NaN3
Purity: at least 99 %
Dissolved in: water deionised
Concentration: 10 µg/plate

Strains: TA1537,TA98
Name: 4-nitro-o-phenylene-diamine, 4-NOPD
Purity: > 99.9 %
Dissolved in: DMSO (MERCK, D-64293 Darmstadt; purity > 99 %)
Concentration: 10 µg/plate in TA 98, 50 µg/plate in TA 1537

Strains: WP2 uvrA
Name: methyl methane sulfonate, MMS
Purity: > 99.0 %
Dissolved in: water deionised
Concentration: 4 µI/plate

With metabolic activation

Strains: TA 1535, TA 1537, TA 98, TA 100, WP2 uvrA
Name: 2-aminoanthracene, 2-AA
Purity: 97.5 %
Dissolved in: DMSO (MERCK, D-64293 Darmstadt; purity > 99 %)
Concentration: 2.5 µg/plate, 10 µg/plate in strain WP2 uvrA

Evaluation criteria:

The Salmonella typhimurium and Escherichia coli reverse mutation assay is considered acceptable if it meets the following criteria:
- regular background growth in the negative and solvent control
- the spontaneous reversion rates in the negative and solvent control are in the range of our historical data
- the positive control substances should produce a significant increase in mutant colony frequencies
A test item is considered as a mutagen if a biologically relevant increase in the number of revertants exceeding the threshold of twice (strains TA 98, TA 100, and WP2 uvrA) or thrice (strains TA 1535 and TA 1537) the colony count of the corresponding solvent control is observed.
A dose dependent increase is considered biologically relevant if the threshold is exceeded
at more than one concentration.
An increase exceeding the threshold at only one concentration is judged as biologically relevant if reproduced in an independent second experiment.
A dose dependent increase in the number of revertant colonies below the threshold is regarded as an indication of a mutagenic potential if reproduced in an independent second experiment. However, whenever the colony counts remain within the historical range of negative and solvent controls such an increase is not considered biologically relevant.

Statistics:

No statistical evaluation of the data is required.

Results and discussion

Test results

Species / strain:

other: Salmonella typhimurium strains TA 1535, TA 1537, TA 98, and TA 100, and the Escherichia coli strain WP2 uvrA.

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

Additional information on results:

ADDITIONAL INFORMATION ON CYTOTOXICITY: No relevant toxic effects were observed and 5000 µg/plate were chosen as maximal concentration.

PRECIPITATION: The test item precipitated in the overlay agar at 3 µg/plate and above. The undissolved particles had no influence on the data recording.

MUTAGENICITY: No substantial increase in revertant colony numbers of any of the five tester strains was observed following treatment 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.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table of Test Results: Number of revertants in the control or after treatment with the testsubstance:

Standard plate test (33 - 5000 µg/plate)
Strain	Metabolic activation system	mean revertants in Controls	maximum revertant factor	dose dependency	Assessment
TA 1535	no	16	0.7	no	negative
	yes	13	1.1	no	negative
TA 1537	no	8	0.8	no	negative
	yes	14	09.	no	negative
TA 98	no	19	0.9	no	negative
	yes	31	1.0	no	negative
TA 100	no	138	1.0	no	negative
	yes	163	1.1	no	negative
E. coli WP2 uvrA	no	50	1.0	no	negative
	yes	41	1.2	no	negative
Preincubation test (33 - 5000 µg/plate)
Strain	Metabolic activation system	mean revertants in Controls	maximum revertant factor	dose dependency	Assessment
TA 1535	no	12	1.4	no	negative
	yes	14	1.0	no	negative
TA 1537	no	6	1.1	no	negative
	yes	7	1.0	no	negative
TA 98	no	22	0.5	no	negative
	yes	25	1.0	no	negative
TA 100	no	116	0.9	no	negative
	yes	148	1.1	no	negative
E. coli WP2 uvrA	no	30	0.9	no	negative
	yes	35	1.3	no	negative

Applicant's summary and conclusion

Conclusions:

The test material failed to induce statistically significant reverse mutations in bacteria under the conditions of the test.