N-phenyl-N-[(trichloromethyl)thio]benzenesulphonamide

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / micronucleus study

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study according to GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2013

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: OECD Guideline for the testing of chemicals 487. In vitro mammalian cell micronucleus test OECD (2010)

Deviations:

no

Principles of method if other than guideline:

The purpose of this study was to investigate whether Vulkalent E (N-phenyl-N-[(trichloromethyl)thio]benzenesulphonamide, CAS no.: 2280-49-1) can induce chromosome breakage (structural chromosomal aberrations) or misdistribution of chromosomes leading to aneuploidy, both of which are measured by an increase of the frequency of micronuclei containing mammalian cells in the absence and presence of an extrinsic metabolizing system.

Vulkalent E, dissolved in tetrahydrofuran, was examined for mutagenic activity in the micronucleus test in vitro. The 4 hours treatment was conducted with concentrations of 0.01, 0.05, 0.1, 0.25, 0.5, 0.75, 1, 2.5 and 5 μg/mL without S9 mix and of 0.5, 1, 2.5, 5, 10, 15, 20, 25 and 100 μg/mL with S9 mix.

The in vitro mammalian cell micronucleus test was conducted according to the OECD Guideline for the testing of chemicals 487 (2010).

GLP compliance:

yes

Type of assay:

in vitro mammalian cell micronucleus test

Test material

Test material information

Constituent 1

Reference substance name:

N-phenyl-N-[(trichloromethyl)thio]benzenesulphonamide

EC Number:

218-915-0

EC Name:

N-phenyl-N-[(trichloromethyl)thio]benzenesulphonamide

Cas Number:

2280-49-1

Molecular formula:

C13H10Cl3NO2S2

IUPAC Name:

N-phenyl-N-[(trichloromethyl)sulfanyl]benzenesulfonamide

Test material form:

not specified

Details on test material:

Purity: 99.8%

Method

Target gene:

When cytogenetic damages leading to chromosomal breakage (clastogenic effects) or
misdistribution of chromosomes (aneugenic effects) are induced during mitosis, chromosomal
fragments or a whole chromosome may be separated from the main nucleus. In interphase the
separated fragment or chromosome can form a tiny nucleus (micronucleus) that exists
independently of the main nucleus in the cytoplasm.
Micronuclei can be seen in a wide variety of cell types. In the micronucleus test employed in
the present study in vitro cultivated V79 cells were used. V79 cells were derived from fetal
lung tissue of Chinese hamsters and are one of the cell lines most widely used for
mutagenicity studies (3). In common with all cell lines they do not possess the full ability of
mammals to activate promutagenic and procarcinogenic compounds. To overcome this
deficiency the compounds are tested in the presence of an exogenous metabolizing system.
Postmitochondrial supernatant fraction from liver of Aroclor 1254-treated male rats and a
NADPH-generating system have been successfully used in prokaryotic and eukaryotic in vitro
systems for the activation of various compounds.

Species / strain

Species / strain / cell type:

Chinese hamster lung fibroblasts (V79)

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

Postmitochondrial supernatant fraction from liver of Aroclor 1254-treated male rats (S9).

Test concentrations with justification for top dose:

Vulkalent E, dissolved in tetrahydrofuran, was examined for mutagenic activity in the
micronucleus test in vitro. The 4 hours treatment was conducted with concentrations of 0.01,
0.05, 0.1, 0.25, 0.5, 0.75, 1, 2.5 and 5 μg/mL without S9 mix and of 0.5, 1, 2.5, 5, 10, 15, 20,
25 and 100 μg/mL with S9 mix.

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

yes

Positive controls:

yes

Positive control substance:

cyclophosphamide

mitomycin C

Results and discussion

Test results

Species / strain:

Chinese hamster lung fibroblasts (V79)

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Any other information on results incl. tables

Vulkalent E, dissolved in tetrahydrofuran, was examined for mutagenic activity in the

micronucleus test in vitro. The 4 hours treatment was conducted with concentrations of 0.01,

0.05, 0.1, 0.25, 0.5, 0.75, 1, 2.5 and 5 μg/mL without S9 mix and of 0.5, 1, 2.5, 5, 10, 15, 20,

25 and 100 μg/mL with S9 mix.

Without S9 mix cytotoxic effects were observed at 0.25 μg/mL and above after 4 hours

treatment. With S9 mix cytotoxic effects were observed at 15 μg/mL and above. Precipitation

in the medium could be observed starting at 100 μg/mL.

Therefore, concentrations of 0.1, 0.25 and 0.5 μg/mL (without S9 mix, 4 hours treatment) 2.5,

10 and 15 μg/mL (with S9 mix, 4 hours treatment) were chosen for reading. Higher

concentrations were excluded from evaluation for micronuclei due to excessive cytotoxicity.

Solvent control (tetrahydrofuran) and appropriate positive controls with known mutagens

(mitomycin C, cyclophosphamide) demonstrated the suitability and sensitivity of the test

system.

The micronucleus test showed a biologically relevant increase in the frequencies of

micronucleus containing V79 cells treated with the test item in the absence or in the presence

of S9 mix (4 hours treatment). Thus, an independent repeat experiment with extended

treatment time in the absence of S9 mix was not performed in accordance with OECD 487.

Evaluation of the data indicates that Vulkalent E is a mutagen in the micronucleus test in

vitro, when tested up to cytotoxic concentrations in the absence or presence of metabolic

activation.

Applicant's summary and conclusion

Executive summary:

The micronucleus test showed a biologically relevant increase in the frequencies of

micronucleus containing V79 cells treated with the test item in the absence or in the presence

of S9 mix (4 hours treatment). Thus, an independent repeat experiment with extended

treatment time in the absence of S9 mix was not performed in accordance with OECD 487.

Evaluation of the data indicates that Vulkalent E is a mutagen in the micronucleus test in

vitro, when tested up to cytotoxic concentrations in the absence or presence of metabolic

activation.