Benzene-1,3-dicarbonitrile

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The mutagenicity in 1,3-dicyanobenzene was examined in a reverse mutation test using bacteria and a negative result was obtained.

With five strains of Salmonella typhimurium (TA100, TA1535, TA98, TA1537) and Escherichia coli WP2 uvrA serving as the test bacteria, a dose setting test and a main test were conducted using the plate method under the conditions in which an S9 mix was added and not added.When a dose setting test was performed at doses from 50 to 5000 μg per plate, antibacterial activity was not observed in any of the test bacteria in the S9 mix free test and in the S9 mix test. Therefore, the S9 mix free test and S9 mix test were conducted at doses set in a range from 313 to 5000 μg/plate.

As a result, no increase in the number of revertant colonies more than twice that of the solvent control value was observed at any dose in the five types of test bacteria used in the two tests. 1,3-dicyanobenzene was determined not to be mutagenic (negative) in the test systems used.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1994; specific dates not available.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

GLP study conducted by Japanese laboratories at the request of Japanese government. Report is translated by approved translation company.

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 472 (Genetic Toxicology: Escherichia coli, Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

Not specified

Target gene:

Histidine and Tryptophan

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:

S9 prepared by enzyme induction from seven-week-old Sprague-Dawley male rats using combined administration of phenobarbital (PB) and 5,6-benzoflavone (BF) (Kikkoman, Lot No. RAA-317, prepared on October 27, 1994) was used. The doses of PB and BF were PB 30 mg/kg on Day 1, PB 60 mg/kg on Day 2, PB 60 mg/kg and BF 80 mg/kg on Day 3, and PB 60 mg/kg on Day 4. Because all were intraperitoneally administered, rat dissection and S9 preparation were on Day 5.

Test concentrations with justification for top dose:

0, 50, 150, 500, 1500, 5000 μg per plate

Vehicle / solvent:

Acetone

Untreated negative controls:

no

Negative solvent / vehicle controls:

no

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

sodium azide

other: 2-(2-furyl)-3-(5-nitro-2-furyl) acrylamide, 2-Aminoanthracene

Details on test system and experimental conditions:

0.1 mL of the test substance preparation solution, 0.5 mL of phosphate buffer (0.5 mL S9 mix in the S9 mix addition test), 0.1 mL of the test bacteria solution, and 2 mL of top agar were mixed in a small test tube, and then poured into a synthetic medium plate and hardened. As control groups, several commonly used solvents and positive control substance solutions were used instead of the test substance preparation.
Culturing was conducted at 37°C for 48 hours, and the number of mutant colonies produced was calculated. The presence or absence of antibacterial activity was determined from the state of the fungal film on the surface of the agar observed with the naked eye or under a stereomicroscope. In the dose setting study, three plates each were used for the solvent and positive control groups and one for each dose. In this test, three samples were used for both control groups and each dose, and the average value and the standard deviation were obtained. The dose setting test was performed once, and the main test was performed twice on the same dose, and the reproducibility of the results was confirmed.

Rationale for test conditions:

As per guideline.

Evaluation criteria:

The test substance was determined to be mutagenic (positive) in this test system when, among the five types of test bacteria used, the average number of mutant colonies on the plate containing the test substance was higher than that of the solvent control in one or more test bacteria whether the S9 mix was added or the S9 mix was not added and when the increase was reproducible or dose-dependent.

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

True negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

True negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium 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

True negative controls validity:

not applicable

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not applicable

True negative controls validity:

not applicable

Positive controls validity:

valid

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:

not applicable

True negative controls validity:

not applicable

Positive controls validity:

valid

Additional information on results:

The DCB doses were tested with a common ratio of 2 in a range from 313 to 5000 μg per plate in both the S9 mix addition test and the S9 mix-free test. As a result, in these two tests, no increase in the number of mutant colonies more than twice that of the solvent control value was observed for the five types of test bacteria used in the S9 mix addition test and the S9 mix-free test.

In all of the DCB tests conducted, the positive control group showed an increase in the number of mutant colonies for all of the test bacteria, but the number of mutant colonies measured in the solvent control group was within the range of historical control values. This confirmed the effectiveness of the test system.

Dose Setting Test
When DCB was tested at a common ratio of about 3 in a range from 50 to 5000 μm per plate, no antibacterial activity was observed in any of the test bacteria in the S9 mix addition test and the S9-free test.

Therefore, the maximum dose in this study was 5000 μg per plate for both the S9 mix addition test and the S9 mix-free test.

Main Tests

The results from the two main tests are shown in Tables 2 and 3, respectively. The DCB doses were tested with a common ratio of 2 in a range from 313 to 5000 μg per plate in both the S9 mix addition test and the S9 mix-free test. As a result, in these two tests, no increase in the number of mutant colonies more than twice that of the solvent control value was observed for the five types of test bacteria used in the S9 mix addition test and the S9 mix-free test.

In all of the DCB tests conducted, the positive control group showed an increase in the number of mutant colonies for all of the test bacteria, but the number of mutant colonies measured in the solvent control group was within the range of historical control values. This confirmed the effectiveness of the test system.

Based on these results, 1,3-dicyanobenzene was determined to be non-mutagenic (negative) in the test system used.

Remarks on result:

other:

Remarks:

No mutagenic

Conclusions:

Based on these results, 1,3-dicyanobenzene was determined to be non-mutagenic (negative) in the test system used.

Executive summary:

The mutagenicity in 1,3-dicyanobenzene was examined in a reverse mutation test using bacteria and a negative result was obtained.

With five strains of Salmonella typhimurium (TA100, TA1535, TA98, TA1537) and Escherichia coli WP2 uvrA serving as the test bacteria, a dose setting test and a main test were conducted using the plate method under the conditions in which an S9 mix was added and not added.When a dose setting test was performed at doses from 50 to 5000 μg per plate, antibacterial activity was not observed in any of the test bacteria in the S9 mix free test and in the S9 mix test. Therefore, the S9 mix free test and S9 mix test were conducted at doses set in a range from 313 to 5000 μg/plate.

As a result, no increase in the number of revertant colonies more than twice that of the solvent control value was observed at any dose in the five types of test bacteria used in the two tests. 1,3-dicyanobenzene was determined not to be mutagenic (negative) in the test systems used.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)