2-octadecyl-1H-thioxantheno[2,1,9-def]isoquinoline-1,3(2H)-dione

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:

2005

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Study according to current guideline and GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

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-octadecyl-1H-thioxantheno[2,1,9-def]isoquinoline-1,3(2H)-dione

EC Number:

248-702-8

EC Name:

2-octadecyl-1H-thioxantheno[2,1,9-def]isoquinoline-1,3(2H)-dione

Cas Number:

27870-92-4

Molecular formula:

C36H45NO2S

IUPAC Name:

14-octadecyl-8-thia-14-azapentacyclo[10.6.2.0²,⁷.0⁹,¹⁹.0¹⁶,²⁰]icosa-1(19),2,4,6,9,11,16(20),17-octaene-13,15-dione

Details on test material:

- Analytical purity: >/= 98 %

Method

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

Rat liver S9 mix

Test concentrations with justification for top dose:

0; 3; 1 0; 33; 100; 333; 1000; 2500; and 5000 µg/plate

Vehicle / solvent:

DMSO (MERCK, D-64293 Darmstadt; purity > 99 %).

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

methylmethanesulfonate

other: 4-nitro-o-phenylene-diamine (4-NOPD); 2-aminoanthracene (2-AA)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium; in agar (plate incorporation); preincubation; in suspension; as impregnation on paper disk

DURATION
- Preincubation period: 60 minutes
- Exposure duration: >48 h

NUMBER OF REPLICATIONS: 3

DETERMINATION OF CYTOTOXICITY
- Method: other: evaluation of back ground lawn and number of spontaneous revertant colonies

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.

Results and discussion

Test results

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

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.

Executive summary:

This study was performed to investigate the potential of the test item to induce gene mutations in 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 rat liver microsomal activation. Each concentration, including the controls, was tested in triplicate. The test item was tested at the following concentrations:

0; 3; 1 0; 33; 1 00; 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. Toxic effects, evident as a reduction in the number of revertants, were observed at the higher concentrations with and without metabolic activation in strains TA 1537, TA 98, and TA 100 in experiment I.

No toxic effects were observed in experiment II.

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.

Conclusion

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.