3-nitro-p-toluic acid

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:

2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: well performed OECD study with GLP

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

3-nitro-p-toluic acid

EC Number:

202-549-3

EC Name:

3-nitro-p-toluic acid

Cas Number:

96-98-0

Molecular formula:

C8H7NO4

IUPAC Name:

4-methyl-3-nitrobenzoic acid

Details on test material:

purity: 98.0 %

Method

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

E. coli WP2 uvr A

Metabolic activation:

with and without

Metabolic activation system:

rat S9-mix

Test concentrations with justification for top dose:

5.0, 2.5, 1.25, 0.625 and 0.312 mg/plate

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

9-aminoacridine

2-nitrofluorene

sodium azide

other: 2-Aminoanthracene,

Details on test system and experimental conditions:

Plate incorporation method was carried out with concentrations of 5.0, 2.5, 1.25, 0.625 and 0.312 mg/plate; where the test item, solvent, positive control and the tester strains along with S9/Phosphate Buffer Saline were mixed with 2 mL soft agar and poured on to Minimal Glucose Agar plates. Five concentrations of the test item were plated, with each of the following tester strains: TA98, TA100, TA1535, TA1537 and E. coli WP2 uvrA (pKM 101) with and without metabolic activator. Plates were incubated at 37°C for 48 hrs.

Statistics:

The data of number of revertants were subjected to computer statistical processing using Graphpad prism software version 5 wherever possible.
. Differences between the solvent control, treatment with different concentrations of test item and positive control groups were tested by one-way ANOVA with Dunnett’s ‘t’ test at a 5% level (p<0.05) of significance.

Results and discussion

Test results

Test results 1

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

not determined

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Test results 2

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

positive

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):
positive

3-Nitro-p-toluic acid is found to be mutagenic at and up to the highest concentration of 5 mg/plate in Bacterial Reverse Mutation Test in the presence and absence of metabolic activator

Executive summary:

The test item 3-Nitro-p-toluic acid wasevaluated for mutagenicity in Bacterial Reverse Mutation Test as per the OECD guideline for the testing of chemicals No. 471, “Bacterial Reverse Mutation Test”, adopted on21^stJuly 1997.

The test item 3-Nitro-p-toluic acid was assessed for its mutagenic effects using Salmonella typhimurium strains: TA98, TA100, TA1535, TA1537 and E. coli WP2 uvrA (pKM101) strain. The test item was tested at the concentrations of 5.0, 2.5, 1.25, 0.625 and 0.312 mg/plate using Dimethyl Sulphoxide (DMSO) as solvent based on the initial cytotoxicity test. The study was conducted, with and without the metabolic activator (S9 fraction). The S9 fraction was prepared from Sodium Phenobarbitone and β-Naphthoflavone induced rat liver. Solvent control and appropriate positive controls (2-nitrofluorene, sodium azide and 9-Aminoacridine, 4-nitroquinoline 1-oxide for trials “without metabolic activator” and 2-Aminoanthracene for trials “with metabolic activator”) were tested simultaneously. One trial was carried out for this study in triplicates with Plate Incorporation method (Trial I). Data was statistically analyzed and expressed as mean ±SD.

From the experimental results obtained, the mean numbers of revertant colonies at and below 5 mg/plate showed positive results in plate incorporation method compared to solvent control, in the presence and absence of metabolic activation. There was significant increase in number of revertant colonies tested at different concentrations.

From the results obtained, the test item 3-Nitro-p-toluic acid is found to be mutagenic at and up to the highest concentration of 5 mg/plate in Bacterial Reverse Mutation Test in the tester strainSalmonella typhimurium: TA98, TA100, TA1535, TA1537 andEscherichia coliWP2 uvrA (pKM101)in the presence and absence of metabolic activator in plate incorporation method under laboratory conditions applied.