2,5-xylidine

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Salmonella Mutagenicity Tests of test chemical was performed in Salmonella strain TA98, TA100, TA1535, TA 1537 and TA97 in the presence and absence of S9 metabolic activation system produced mutation, therefore it is considered to be positive for gene mutation in vitro.

Link to relevant study records

Reference

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:

data from handbook or collection of data

Justification for type of information:

Data is from publication

Qualifier:

according to guideline

Guideline:

other: As mentioned below

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Target gene:

Histidine

Species / strain / cell type:

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

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

10%HLI and 10%RLI

The S-9 (9000g supernatant) fractions of Aroclor 1254-induced, male Sprague- Dawley rat and male Syrian hamster livers were prepared. The S-9 mixes were prepared immediately prior to use and contained either 10% or 30% S-9; occasionally, other levels were used.

Test concentrations with justification for top dose:

Dose :
0, 33, 100, 333, 1000 and 1666 µg/plate

Vehicle / solvent:

Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: The test chemical was soluble in DMSO

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

Remarks:

Dimethyl Sulfoxide

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

Control for- test without S9 activation (TA 1535 and TA 100)

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

Remarks:

Dimethyl sulfoxide

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

Absence of metabolic activation (TA 97 and TA 1537)

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

Remarks:

Dimethyl sulfoxide

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 4-nitro-o-phenylenediamine

Remarks:

With metabollic activation (TA 98)

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

yes

Remarks:

Dimethyl Sulfoxide

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

Control for- test with HLI and RLI S9 activation

Rationale for test conditions:

Not specified

Evaluation criteria:

A chemical was judged mutagenic (+) or weakly mutagenic (+ W) if it produced a reproducible dose-related reponse over the solvent control in replicate trials.
The chemicals were decoded by the chemical repository only after a determination had been made regarding their mutagenicity or nonmutagenicity. The plate count means are presented in Appendix 2 so that the reader has the opportunity of performing his or her own evaluation of the data.

Statistics:

Not specified

Species / strain:

other: S. typhimurium TA 1535, 100, 97, 98

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Species / strain:

other: S. typhimurium TA 1537, 100, 98

Metabolic activation:

with

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Species / strain:

other: S. typhimurium TA 1535, 1537, 100, 97

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Species / strain:

other: S. typhimurium TA 1535, 97

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Strain: TA 100

Dose	NA (-)		10% HLI (+)		10% RLI (+W)
µg/plate	Mean	SEM	Mean	SEM	Mean	SEM
0.000	152	13.9	173	2.4	143	15.5
33.000	137	18.8	271	21.4	194	3.8
100.000	133	2.9	301	4.1	213	2.9
333.000	116	6.4	409	14.1	254	3.4
1000.000	139	10.8	451	9.0	265	13.7
1666.000	23S	5.0	446	17.0	235	13.2
POS	500	4.1	1007	31.3	953	15.3

               

Strain:TA1537

Dose	10% HLI (+)		10% RLI (-)
µg/plate	Mean	SEM	Mean	SEM
0.000	5	1.7	12	0.3
33.000	9	2.8	9	0.9
100.000	11	1.5	12	1.7
333.000	19	3.3	13	1.5
1000.000	25	0.7	17	0.9
1666.000	43	4.6	14	0.7
POS	322	21.1	153	5.0

 

 

Strain:TA97

Dose	NA (?)		10% HLI (+W)		10% RLI (-)
µg/plate	Mean	SEM	Mean	SEM	Mean	SEM
0.000	118	9.3	196	3.5	183	16.9
33.000	181	4.4	214	17.8	178	2.5
100.000	187	5.9	213	3.5	179	12.5
333.000	179	4.7	264	6.0	158	6.1
1000.000	157	13.1	272	17.7	187	16.2
1666.000	81S	12.3	290	21.0	82S	21.2
POS	652	9.1	777	23.3	638	5.9

 

 

 

Strain:TA98

Dose	NA (-)		10% HLI (+)		10% RLI (+)
µg/plate	Mean	SEM	Mean	SEM	Mean	SEM
0.000	30	1.2	42	3.5	40	0.0
33.000	28	4.2	46	2.8	36	4.1
100.000	31	2.8	59	3.0	46	2.7
333.000	25	3.1	105	4.1	67	3.2
1000.000	24	5.3	187	8.2	97	15.0
1666.000	5S	1.3	292	4.5	92	8.1
POS	814	36.0	549	23.5	403	37.4

Strain : TA 1535

Dose	No Activation (Negative)		10% HLI (Negative)		10% RLI (Negative)
Protocol	Preincubation		Preincubation		Preincubation
ug/Plate	Mean	± SEM	Mean	± SEM	Mean	± SEM
0	34	3.3	12	1.2	13	1.5
33	35	1.9	11	1.3	14	0.9
100	36	4.9	10	1.9	10	1.5
333	30	0.3	15	0.3	12	2
1000	36	2.6	13	0.3	9	0.9
1666	2s	0.6	10	0.6	12	2.1
Positive Control	468	11.5	269	9.5	245	15.9

Abbreviations:
RLI = induced male Sprague Dawley rat liver S9
HLI = induced male Syrian hamster liver S9
s = Slight Toxicity; p = Precipitate; x = Slight Toxicity and Precipitate; T = Toxic; c = Contamination

Conclusions:

Salmonella Mutagenicity Tests of test chemical was performed in Salmonella strain TA98, TA100, TA1535, TA 1537 and TA97 in the presence and absence of S9 metabolic activation system produced mutation, therefore it is considered to be positive for gene mutation in vitro.

Executive summary:

Gene mutation toxicity study was performed to determine the mutagenic nature of the test chemical. The study was performed using Salmonella typhimurium strains TA98, TA97, TA100, TA1537 and TA1535 in the presence and absence of 10% Hamster Liver Infusion S9 and 10% Rat Liver Infusion S9 metabolic activation system. The chemical was dissolved in DMSO as solvent and used at dose levels 0, 33.0, 100.0, 333.0, 1000.0 and 1666.0 µg/plate by the preincubation method. Sodium azide, 9-aminocridine, 4-nitro-o-phenylenediamine and 2-aminoanthracene were used as positive control substances in the presence and absence of metabolic activation.

Genetic toxicity of test chemical to Salmonella typhimurium strain TA1535, TA100, TA97 and TA 98 was observed to be negative without S9 metabolic activation. Salmonella typhimurium strain TA1537, TA100 and TA 98 was observed to be negative with hamster, liver, S-9, aroclor 1254 (10%) induced metabolic activation. Salmonella typhimurium Strain TA1537, TA100, TA 1535 and TA 97 was observed to be negative with rat, liver, s-9, aroclor 1254 (10%) induced metabolic activation.

From the above observations it can be concluded that the test chemical is weakly mutagenic in nature.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (positive)

Additional information

Data available for the target chemical was reviewed to determine the mutagenic nature of the test chemical. The studies are as mentioned below:

Gene mutation toxicity study was performed to determine the mutagenic nature of the test chemical. The study was performed using Salmonella typhimurium strains TA98, TA97, TA100, TA1537 and TA1535 in the presence and absence of 10% Hamster Liver Infusion S9 and 10% Rat Liver Infusion S9 metabolic activation system. The chemical was dissolved in DMSO as solvent and used at dose levels 0, 33.0, 100.0, 333.0, 1000.0 and 1666.0 µg/plate by the preincubation method. Sodium azide, 9-aminocridine, 4-nitro-o-phenylenediamine and 2-aminoanthracene were used as positive control substances in the presence and absence of metabolic activation.

Genetic toxicity of test chemical to Salmonella typhimurium strain TA1535, TA100, TA97 and TA 98 was observed to be negative without S9 metabolic activation. Salmonella typhimurium strain TA1537, TA100 and TA 98 was observed to be negative with hamster, liver, S-9, aroclor 1254 (10%) induced metabolic activation. Salmonella typhimurium Strain TA1537, TA100, TA 1535 and TA 97 was observed to be negative with rat, liver, s-9, aroclor 1254 (10%) induced metabolic activation.

From the above observations it can be concluded that the test chemical is weakly mutagenic in nature.

In another study, Gene mutation toxicity study was performed to determine the mutagenic nature of the test chemical. The study was performed using Salmonella typhimurium strains TA98, TA100 and TA1537 in the presence and absence of Rat Liver Infusion S9 metabolic activation system. The chemical was dissolved in DMSO as solvent and used at dose levels 0.1 ml by the salmonella/microsome method.

Salmonella typhimurium strains TA98 and TA1537 did not show mutagenic nature in the absence of S9 metabolic activation. Whereas, 58 revertants /µmole/plate were observed in the agar plate and weakly positive results were observed in Salmonella typhimurium strain TA100 in the he presence of S9 metabolic activation system. Therefore the test chemical is considered to be mutagenic in nature.

Based on the data available for the test chemical, the test chemical induced mutation in the Salmonella typhimurium strain TA98, TA97, TA100, TA1535 or TA1537 both in the presence and absence of S9 metabolic activation system and hence is likely to be mutagenic under the conditions of this study.

Justification for classification or non-classification

Based on the observations made, the test chemical exibits gene mutation in vitro . Hence it is likely to classify as a gene mutant in vitro as per the criteria mentioned in CLP regulation.