o-toluidine

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: guideline study with restrictions

Data source

Reference

Reference 1

Reference Type:

publication

Title:

Mutation tests with Salmonella using the plate-incorporation assay

Author:

Rexroat MA and Probst GS

Year:

1985

Bibliographic source:

Progress in Mutation Research 5, 201-212

Reference 2

Reference Type:

publication

Title:

o-TOLUIDINE CAS No: 95-53-4 SIDS Initial Assessment Report.

Author:

OECD SIDS

Year:

2006

Bibliographic source:

UNEP Publications

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

Toxicity was not reached, no data on purity of the test substance

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

o-toluidine

EC Number:

202-429-0

EC Name:

o-toluidine

Cas Number:

95-53-4

Molecular formula:

C7H9N

IUPAC Name:

2-methylaniline

Test material form:

not specified

Details on test material:

- Name of test material (as cited in study report): o-toluidine
- Analytical purity: no data

Method

Target gene:

his+

Species / strain

Species / strain / cell type:

other: TA 98, TA 100, TA 1535, TA 1537, TA 1538

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9 mix liver homogenates from Aroclor 1254 induced rats

Test concentrations with justification for top dose:

0, 50, 100, 500, 1000, 5000 µg/plate in DMSO

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

other: 9-aminoacridine; 2-Nitrofluorene; N-Methyl-N'-nitro-N-nitrososguanidine. 2-Aminoanthracene

Details on test system and experimental conditions:

plate-incorporation assay

Evaluation criteria:

Criteria for a positive rsponse: A chemical was judged to have induced a positive response when a dose -related increase in revertants was observed in which the number of revertants exceeded the control values by at least tow-fold in at least two successive concentrations of the test chemical

Results and discussion

Test results

Species / strain:

other: TA 98, TA 100, TA 1535, TA 1537, TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Remarks:

> 5000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Additional information on results:

The positive controls increased mutant counts to well over those of the negative controls, and thus demonstrated the system's sensitivity and the
activity of the S9 mix.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Tab 1. Evaluation of o-toluidine for induction of bacterial mutation using the Ames test

 

Treatment	µg/plate	Revertant colony counts (mean ± SD)^a
		TA1535	TA1537	TA1538	TA98	TA100
Test without metabolic activation
DMSO^b	0.05 ml	18 ± 5	6 ± 1	15 ± 3	27 ± 6	141 ± 12
DMSO^c	0.05 ml	18 ± 2	8 ± 4	13 ± 1	23 ± 2	138 ± 13
o-toluidine	50	18 ± 6	6 ± 1	13 ± 3	25 ± 5	146 ± 7
	100	25 ± 3	10 ± 3	11 ± 4	32 ± 7	141 ± 16
	500	28 ± 3	8 ± 4	14 ± 3	20 ± 1	140 ± 18
	1000	27 ± 5	8 ± 2	12 ± 6	24 ± 3	130 ± 6
	5000	35 ± 11	6 ± 1	16 ± 2	22 ± 7	153 ± 12
MNNG^d	2.5	1728 ± 131
MNNG	5	3319 ± 56
9AmAc^d	50		141 ± 28
9AmAc	100		1433 ± 47
2-NF^d	0.5			105 ± 4	64 ± 10
2-NF	5			900 ± 36	603 ± 66
Test with metabolic activation
DMSO^b	0.05 ml	20 ± 1	8 ± 2	23 ± 3	31 ± 11	102 ± 7
DMSO^c	0.05 ml	17 ± 1	7 ± 1	20 ± 3	32 ± 1	118 ± 3
o-toluidine	50	15 ± 1	9 ± 4	19 ± 7	29 ± 3	118 ± 13
	100	13 ± 4	8 ± 3	19 ± 4	32 ± 6	107 ± 4
	500	13 ± 4	4 ± 1	19 ± 2	36 ± 1	117 ± 5
	1000	16 ± 2	8 ± 2	21 ± 3	33 ± 1	127 ± 3
	5000	14 ± 3	12 ± 2	22 ± 3	40 ± 9	142 ± 8
2-AA^d	2.5	176 ± 15	259 ± 22	1700 ± 99	1922 ± 20	2370 ± 37
2-AA	5	202 ± 30	156 ± 38	1791 ± 88	2905 ± 53	2849 ± 100

 a Mean ± SD deviation of counts from triplicate plates. Values represent corrected counts fro 100% of the plate area.

 ^{b DMSO control value for the tester strain plated at the initiation of plating ; c DMSO control value fo tester strain plated at the termination of plating; d In the nonactivated test MNNG served as the positive control for strains TA 1535 and TA 100; 9 AmAc was the positve control for the strain TA1537; and 2 NF served as the positive control for the strains TA1538 and TA 98. In the activated test, 2AA served as the positive control for all test strains.}

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

Executive summary:

o-toluidine was tested for the induction of bacterial mutation using five histidine auxotrophs of Salmonella typhimurium TA135, TA1537, TA1538, TA100, TA98 according to OECD guideline 471 (plate incorporation methodology) with acceptable deviations (Toxicity was not reached, no data on purity of the test substance). The test was conducted with and without metabolic activation using an S9 fraction prepared from the livers of Aroclor-1254-induced rats. N-Methyl-N´-nitro-N-nitrosoguanidine (MNNG), 2-nitrofluorene (2NF), and 9-aminoacridine (9AmAc) served as the positive controls for the nonactivated test, while 2-aminoanthracene (2AA) served as the positive control for the activated test. Either with or without metabolic activation no revertants were induced by treatment with o-toluidine.