3-(1-(4-amino-3-methyl-5-sulphonatophenyl)-1-(4-amino-3-sulphonatophenyl)methylene)cyclohexa-1,4-dienesulphonic acid

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, gene mutation was predicted for 2-amino-5-[(4-amino-3-sulfonatophenyl)(3-sulfocyclohexa-2,5-dien-1-ylidene) methyl]-3-methylbenzenesulfonate. The study assumed the use of Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 with S9 metabolic activation system. 2-amino-5- [(4-amino-3-sulfonatophenyl) (3-sulfocyclohexa-2,5-dien-1-ylidene) methyl]-3-methylbenzene sulfonate was predicted to not induce gene mutation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in the presence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Based on the predicted result it can be concluded that the substance is considered to be not toxic as per the criteria mentioned in CLP regulation.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Justification for type of information:

Data is from OECD QSAR Toolbox version 3.3 and the supporting QMRF report has been attached

Qualifier:

according to guideline

Guideline:

other: Refer below principle

Principles of method if other than guideline:

Prediction is done using OECD QSAR Toolbox version 3.3, 2017

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

- Name of the test material: 2-amino-5-[(4-amino-3-sulfonatophenyl)(3-sulfocyclohexa-2,5-dien-1-ylidene)methyl]-3-methylbenzenesulfonate
- IUPAC name: 2-amino-5-[(4-amino-3-sulfonatophenyl)(3-sulfocyclohexa-2,5-dien-1-ylidene)methyl]-3-methylbenzenesulfonate
- Molecular formula: C20H17N3O9S3.2Na
- Molecular weight: 585.5443 g/mol
- Substance type: Organic
- Smiles: C1(S(=O)(=O)O)=C\C(=C(\c2cc(S(=O)(=O)[O-])c(c(c2)C)N)c2cc(S(=O)(=O)[O-])c(cc2)N)C=CC1=N.[Na+].[Na+]

Target gene:

Histidine

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and TA 102

Details on mammalian cell type (if applicable):

Not applicable

Additional strain / cell type characteristics:

not specified

Cytokinesis block (if used):

No data

Metabolic activation:

with

Metabolic activation system:

S9 metabolic activation system

Test concentrations with justification for top dose:

No data

Vehicle / solvent:

No data

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

not specified

Positive control substance:

not specified

Details on test system and experimental conditions:

No data

Rationale for test conditions:

No data

Evaluation criteria:

Prediction is done considering a dose dependent increase in the number of revertants/plate

Statistics:

No data

Species / strain:

S. typhimurium, other: TA 1535, TA 1537, TA 98, TA 100 and TA 102

Metabolic activation:

with

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

No data

Remarks on result:

other: No mutagenic potential

The prediction was based on dataset comprised from the following descriptors: "Gene mutation"
Estimation method: Takes highest mode value from the 7 nearest neighbours
Domain  logical expression:Result: In Domain

((((((((((("a" or "b" or "c" or "d" )  and ("e" and ( not "f") )  )  and ("g" and ( not "h") )  )  and ("i" and ( not "j") )  )  and ("k" and ( not "l") )  )  and ("m" and ( not "n") )  )  and ("o" and ( not "p") )  )  and "q" )  and "r" )  and ("s" and ( not "t") )  )  and ("u" and "v" )  )

Domain logical expression index: "a"

Referential boundary: The target chemical should be classified as Alkene OR Alkyl arenes OR Allyl OR Aniline OR Aryl OR Cycloalkene OR Dianilines OR Sulfonic acid by Organic Functional groups ONLY

Domain logical expression index: "b"

Referential boundary: The target chemical should be classified as Alkene OR Alkyl arenes OR Allyl OR Cycloalkene OR Dianilines OR Overlapping groups OR Sulfonic acid by Organic Functional groups (nested) ONLY

Domain logical expression index: "c"

Referential boundary: The target chemical should be classified as Aliphatic Carbon [CH] OR Aliphatic Carbon [-CH2-] OR Aliphatic Carbon [-CH3] OR Aliphatic Nitrogen, one aromatic attach [-N] OR Alkenyl sufide [-S=C] OR Aromatic Carbon [C] OR Hydroxy, sulfur attach [-OH] OR Miscellaneous sulfide (=S) or oxide (=O) OR Olefinic carbon [=CH- or =C<] OR Suflur {v+4} or {v+6} OR Sulfinic acid [-S(=O)OH] OR Sulfonate, aromatic attach [-SO2-O] by Organic functional groups (US EPA) ONLY

Domain logical expression index: "d"

Referential boundary: The target chemical should be classified as Amine OR Aromatic compound OR Primary amine OR Primary aromatic amine OR Sulfonic acid OR Sulfonic acid derivative by Organic functional groups, Norbert Haider (checkmol) ONLY

Domain logical expression index: "e"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OASIS v.1.3

Domain logical expression index: "f"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >>  Michael-type addition, quinoid structures OR AN2 >>  Michael-type addition, quinoid structures >> Quinoneimines OR AN2 >>  Michael-type addition, quinoid structures >> Quinones OR AN2 >> Carbamoylation after isocyanate formation OR AN2 >> Carbamoylation after isocyanate formation >> N-Hydroxylamines OR AN2 >> Nucleophilic addition to alpha, beta-unsaturated carbonyl compounds OR AN2 >> Nucleophilic addition to alpha, beta-unsaturated carbonyl compounds >> alpha, beta-Unsaturated Aldehydes OR AN2 >> Schiff base formation OR AN2 >> Schiff base formation >> alpha, beta-Unsaturated Aldehydes OR Michael addition OR Michael addition >> Quinone type compounds OR Michael addition >> Quinone type compounds >> Quinone methides OR Non-covalent interaction OR Non-covalent interaction >> DNA intercalation OR Non-covalent interaction >> DNA intercalation >> Acridone, Thioxanthone, Xanthone and Phenazine Derivatives OR Non-covalent interaction >> DNA intercalation >> Aminoacridine DNA Intercalators OR Non-covalent interaction >> DNA intercalation >> Fused-Ring Primary Aromatic Amines OR Non-covalent interaction >> DNA intercalation >> Quinones OR Non-specific OR Non-specific >> Incorporation into DNA/RNA, due to structural analogy with  nucleoside bases    OR Non-specific >> Incorporation into DNA/RNA, due to structural analogy with  nucleoside bases    >> Specific Imine and Thione Derivatives OR Radical OR Radical >> Generation of reactive oxygen species OR Radical >> Generation of reactive oxygen species >> Thiols OR Radical >> Radical mechanism by ROS formation OR Radical >> Radical mechanism by ROS formation >> Acridone, Thioxanthone, Xanthone and Phenazine Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) OR Radical >> Radical mechanism via ROS formation (indirect) >> Conjugated Nitro Compounds OR Radical >> Radical mechanism via ROS formation (indirect) >> Fused-Ring Primary Aromatic Amines OR Radical >> Radical mechanism via ROS formation (indirect) >> Hydrazine Derivatives OR Radical >> Radical mechanism via ROS formation (indirect) >> N-Hydroxylamines OR Radical >> Radical mechanism via ROS formation (indirect) >> p-Aminobiphenyl Analogs OR Radical >> Radical mechanism via ROS formation (indirect) >> Quinones OR Radical >> Radical mechanism via ROS formation (indirect) >> Single-Ring Substituted Primary Aromatic Amines OR Radical >> Radical mechanism via ROS formation (indirect) >> Specific Imine and Thione Derivatives OR Radical >> ROS formation after GSH depletion OR Radical >> ROS formation after GSH depletion (indirect) OR Radical >> ROS formation after GSH depletion (indirect) >> Quinoneimines OR Radical >> ROS formation after GSH depletion >> Quinone methides OR SN1 OR SN1 >> Alkylation after metabolically formed carbenium ion species OR SN1 >> Alkylation after metabolically formed carbenium ion species >> Polycyclic Aromatic Hydrocarbon Derivatives OR SN1 >> Nucleophilic attack after carbenium ion formation OR SN1 >> Nucleophilic attack after carbenium ion formation >> Acyclic Triazenes OR SN1 >> Nucleophilic attack after carbenium ion formation >> N-Nitroso Compounds OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Fused-Ring Primary Aromatic Amines OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> N-Hydroxylamines OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> p-Aminobiphenyl Analogs OR SN1 >> Nucleophilic attack after metabolic nitrenium ion formation >> Single-Ring Substituted Primary Aromatic Amines OR SN1 >> Nucleophilic attack after nitrenium and/or carbenium ion formation OR SN1 >> Nucleophilic attack after nitrenium and/or carbenium ion formation >> N-Nitroso Compounds OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation OR SN1 >> Nucleophilic attack after reduction and nitrenium ion formation >> Conjugated Nitro Compounds OR SN1 >> Nucleophilic substitution on diazonium ions OR SN1 >> Nucleophilic substitution on diazonium ions >> Specific Imine and Thione Derivatives OR SN2 OR SN2 >> Alkylation, direct acting epoxides and related OR SN2 >> Alkylation, direct acting epoxides and related >> Epoxides and Aziridines OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation OR SN2 >> Alkylation, direct acting epoxides and related after P450-mediated metabolic activation >> Polycyclic Aromatic Hydrocarbon Derivatives OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom OR SN2 >> Alkylation, nucleophilic substitution at sp3-carbon atom >> Sulfonates and Sulfates OR SN2 >> Direct acting epoxides formed after metabolic activation OR SN2 >> Direct acting epoxides formed after metabolic activation >> Quinoline Derivatives OR SN2 >> SN2 at an activated carbon atom OR SN2 >> SN2 at an activated carbon atom >> Quinoline Derivatives by DNA binding by OASIS v.1.3

Domain logical expression index: "g"

Referential boundary: The target chemical should be classified as No alert found by DNA binding by OECD

Domain logical expression index: "h"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> P450 Mediated Activation to Isocyanates or Isothiocyanates OR Acylation >> P450 Mediated Activation to Isocyanates or Isothiocyanates >> Formamides OR Michael addition OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Arenes OR Michael addition >> P450 Mediated Activation to Quinones and Quinone-type Chemicals >> Polycyclic (PAHs) and heterocyclic (HACs) aromatic hydrocarbons-Michael addition OR Michael addition >> Polarised Alkenes-Michael addition OR Michael addition >> Polarised Alkenes-Michael addition >> Alpha, beta- unsaturated ketones OR Schiff base formers OR Schiff base formers >> Direct Acting Schiff Base Formers OR Schiff base formers >> Direct Acting Schiff Base Formers >> Alpha-beta-dicarbonyl OR SN1 OR SN1 >> Carbenium Ion Formation OR SN1 >> Carbenium Ion Formation >> Polycyclic (PAHs) and heterocyclic (HACs) aromatic hydrocarbons-SN1 OR SN1 >> Iminium Ion Formation OR SN1 >> Iminium Ion Formation >> Aliphatic tertiary amines OR SN1 >> Nitrenium Ion formation OR SN1 >> Nitrenium Ion formation >> Aromatic azo OR SN1 >> Nitrenium Ion formation >> Primary aromatic amine OR SN1 >> Nitrenium Ion formation >> Tertiary aromatic amine OR SN2 OR SN2 >> Direct Acting Epoxides and related OR SN2 >> Direct Acting Epoxides and related >> Sulfuranes OR SN2 >> SN2 at an sp3 Carbon atom OR SN2 >> SN2 at an sp3 Carbon atom >> Sulfonates by DNA binding by OECD

Domain logical expression index: "i"

Referential boundary: The target chemical should be classified as No alert found by Protein binding by OECD

Domain logical expression index: "j"

Referential boundary: The target chemical should be classified as Michael addition OR Michael addition >> Polarised Alkenes OR Michael addition >> Polarised Alkenes >> Polarised alkene - cyano OR Michael addition >> Polarised Alkenes >> Polarised alkene - ketones OR Michael addition >> Polarised Alkenes >> Polarised alkene - pyridines OR Michael addition >> Quinones and Quinone-type Chemicals OR Michael addition >> Quinones and Quinone-type Chemicals >> Quinone-imine by Protein binding by OECD

Domain logical expression index: "k"

Referential boundary: The target chemical should be classified as No Data by Ultimate biodeg

Domain logical expression index: "l"

Referential boundary: The target chemical should be classified as > 100 days OR 0 to 1 day OR 1 to 10 days OR 10 to 100 days by Ultimate biodeg

Domain logical expression index: "m"

Referential boundary: The target chemical should be classified as No alert found by Protein binding alerts for skin sensitization by OASIS v1.3

Domain logical expression index: "n"

Referential boundary: The target chemical should be classified as Acylation OR Acylation >> Direct acylation involving a leaving group OR Acylation >> Direct acylation involving a leaving group >> Azlactones and unsaturated lactone derivatives  OR Michael Addition OR Michael Addition >> Michael addition on conjugated systems with electron withdrawing group OR Michael Addition >> Michael addition on conjugated systems with electron withdrawing group >> Conjugated systems with electron withdrawing groups  OR Nucleophilic addition OR Nucleophilic addition >> Addition to carbon-hetero double bonds OR Nucleophilic addition >> Addition to carbon-hetero double bonds >> Azomethyme type compounds  OR Nucleophilic addition >> Addition to carbon-hetero double bonds >> Ketones OR Schiff base formation OR Schiff base formation >> Schiff base formation with carbonyl compounds OR Schiff base formation >> Schiff base formation with carbonyl compounds >> Aldehydes OR SN2 OR SN2 >> Interchange reaction with sulphur containing compounds OR SN2 >> Interchange reaction with sulphur containing compounds >> Thiols and disulfide compounds  by Protein binding alerts for skin sensitization by OASIS v1.3

Domain logical expression index: "o"

Referential boundary: The target chemical should be classified as No alert found by Protein binding alerts for Chromosomal aberration by OASIS v1.1

Domain logical expression index: "p"

Referential boundary: The target chemical should be classified as AN2 OR AN2 >> Nucleophilic addition to pyridonimine tautomer of aminopyridoindoles or aminopyridoimidazoles OR AN2 >> Nucleophilic addition to pyridonimine tautomer of aminopyridoindoles or aminopyridoimidazoles >> Heterocyclic Aromatic Amines OR Ar OR Ar >> Radical-type addition to imino tautomer of acridines OR Ar >> Radical-type addition to imino tautomer of acridines >> Benzoquinolines and Acridines OR Radical mechanism OR Radical mechanism >> ROS generation and direct attack of hydroxyl radical to the C8 position of nucleoside base OR Radical mechanism >> ROS generation and direct attack of hydroxyl radical to the C8 position of nucleoside base >> Heterocyclic Aromatic Amines OR SE reaction (CYP450-activated heterocyclic amines) OR SE reaction (CYP450-activated heterocyclic amines) >> Direct attack of arylnitrenium cation to the C8 position of nucleoside base OR SE reaction (CYP450-activated heterocyclic amines) >> Direct attack of arylnitrenium cation to the C8 position of nucleoside base >> Heterocyclic Aromatic Amines OR SN2 OR SN2 >> Ring opening nucleophilic subsitution involving proteins and arene oxide derivatives OR SN2 >> Ring opening nucleophilic subsitution involving proteins and arene oxide derivatives >> Benzoquinolines and Acridines OR SNAr OR SNAr >> Nucleophilic subsitution on activated Csp2-atoms in quinolines OR SNAr >> Nucleophilic subsitution on activated Csp2-atoms in quinolines >> Benzoquinolines and Acridines OR SR reaction (peroxidase-activated heterocyclic amines) OR SR reaction (peroxidase-activated heterocyclic amines) >> Direct attack of arylnitrenium radical to the C8 position of nucleoside base OR SR reaction (peroxidase-activated heterocyclic amines) >> Direct attack of arylnitrenium radical to the C8 position of nucleoside base >> Heterocyclic Aromatic Amines by Protein binding alerts for Chromosomal aberration by OASIS v1.1

Domain logical expression index: "q"

Referential boundary: The target chemical should be classified as Class 5 (Not possible to classify according to these rules) by Acute aquatic toxicity classification by Verhaar (Modified) ONLY

Domain logical expression index: "r"

Referential boundary: The target chemical should be classified as Very fast by Bioaccumulation - metabolism half-lives ONLY

Domain logical expression index: "s"

Referential boundary: The target chemical should be classified as Non-Metals by Groups of elements

Domain logical expression index: "t"

Referential boundary: The target chemical should be classified as Alkali Earth OR Alkaline Earth OR Halogens OR Metalloids OR Rare Earth OR Transition Metals by Groups of elements

Domain logical expression index: "u"

Parametric boundary:The target chemical should have a value of log Kow which is >= -2.38

Domain logical expression index: "v"

Parametric boundary:The target chemical should have a value of log Kow which is <= 0.683

Conclusions:

2-amino-5- [(4-amino-3-sulfonatophenyl) (3-sulfocyclohexa-2,5-dien-1-ylidene) methyl]-3-methylbenzene sulfonate was predicted to not induce gene mutation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in the presence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Executive summary:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, gene mutation was predicted for 2-amino-5-[(4-amino-3-sulfonatophenyl)(3-sulfocyclohexa-2,5-dien-1-ylidene) methyl]-3-methylbenzenesulfonate. The study assumed the use of Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 with S9 metabolic activation system. 2-amino-5- [(4-amino-3-sulfonatophenyl) (3-sulfocyclohexa-2,5-dien-1-ylidene) methyl]-3-methylbenzene sulfonate was predicted to not induce gene mutation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in the presence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Based on the predicted result it can be concluded that the substance is considered to be not toxic as per the criteria mentioned in CLP regulation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Gene mutation in vitro:

Prediction model based estimation and data from read across chemicals have been reviewed to determine the mutagenic nature of

2-amino-5-[(4-amino-3-sulfonatophenyl)(3-sulfocyclohexa-2,5-dien-1-ylidene) methyl]-3-methylbenzenesulfonate. The studies are as mentioned below:

Based on the prediction done using the OECD QSAR toolbox version 3.3 with log kow as the primary descriptor and considering the five closest read across substances, gene mutation was predicted for 2-amino-5-[(4-amino-3-sulfonatophenyl)(3-sulfocyclohexa-2,5-dien-1-ylidene) methyl]-3-methylbenzenesulfonate. The study assumed the use of Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 with and without S9 metabolic activation system. 2-amino-5- [(4-amino-3-sulfonatophenyl) (3-sulfocyclohexa-2,5-dien-1-ylidene) methyl]-3-methylbenzene sulfonate was predicted to not induce gene mutation in Salmonella typhimurium strains TA 1535, TA 1537, TA 98, TA 100 and TA 102 in the presence and absence of S9 metabolic activation system and hence, according to the prediction made, it is not likely to classify as a gene mutant in vitro.

Gene mutation toxicity was predicted for 2-amino-5-[(4-amino-3-sulfonatophenyl)(3-sulfocyclohexa-2,5-dien-1-ylidene)methyl]-3-methylbenzenesulfonate using the battery approach from Danish QSAR database (2017). The study assumed the use of Salmonella typhimurium bacteria in the Ames test. The end point for gene mutation has been modeled in the Danish QSAR using the three software systems Leadscope, CASE Ultra and SciQSAR. Based on predictions from these three systems, a fourth and overall battery prediction is made. The battery prediction is made using the so called Battery algorithm. With the battery approach it is in many cases possible to reduce “noise” from the individual model estimates and thereby improve accuracy and/or broaden the applicability domain. Gene mutation toxicity study as predicted by Danish QSAR for 2-amino-5-[(4-amino-3-sulfonatophenyl)(3-sulfocyclohexa-2,5-dien-1-ylidene)methyl]-3-methylbenzenesulfonate is negative and hence the chemical is predicted to not classify as a gene mutant in vitro.

The ability of 2-amino-5-[(4-amino-3-sulfonatophenyl)(3-sulfocyclohexa-2,5-dien-1-ylidene)methyl]-3-methylbenzenesulfonate to induce chromosomal aberration was predicted using Chinese hamster ovary (CHO) cells using Danish QSAR database (2017). The end point for chromosome aberrations has been modeled in the Danish QSAR using the three software systems Leadscope, CASE Ultra and SciQSAR. Based on predictions from these three systems, a fourth and overall battery prediction is made. The battery prediction is made using the so called Battery algorithm. With the battery approach it is in many cases possible to reduce “noise” from the individual model estimates and thereby improve accuracy and/or broaden the applicability domain. 2-amino-5-[(4-amino-3-sulfonatophenyl)(3-sulfocyclohexa-2,5-dien-1-ylidene)methyl]-3-methylbenzenesulfonate does notinduce chromosome aberrations in Chinese hamster ovary (CHO) cells and hence is predicted to not classify as a gene mutant in vitro.

In a study for structurally and functionally similar read across chemical by Zeiger et al (Environmental and Molecular Mutagenesis, 1988), o-Amino benzenesulfonic acid (RA CAS no 88 -21 -1) was studied for its ability to induce mutations in strains of Salmonella typhimurium. The test compound was dissolved in DMSO and was tested at concentration of 10, 33, 100, 333, 1000, 3333, 3334 or 6667 µg/plate using Salmonella typhimurium TA100, TA1535, TA97 and TA98 in the presence and absence of 10 % and 30 % rat and hamster liver S9 metabolic activation system. Preincubation assay was performed with a preicubation for 20 mins. The plates were observed for histidine independence after 2 days incubation period. Concurrent solvent and positive controls were included in the study. o-Amino benzenesulfonic acidis not mutagenic to theSalmonella typhimurium TA100, TA1535, TA97 in the presence and absence of rat and hamster liver S9 metabolic activation system. Some mutagenic activity is noted for the strain TA98 in the absence of S9 metabolic activation system. Since the test chemical does not exhibit gene mutation activity in the presence of S9 metabolic activation system and hence the test chemical is considered to be non mutagenic in vitro.

In a study by Fluck et al (Chemical Biological Interactions, 1976) for structurally and functionally similar read across chemical, Differential growth inhibition of two E. coli cultures (DNA polymerase deficient strain P3478 and parent strain P3110) was evaluated as a rapid screening technique for evaluating the mutagenic nature of Methane sulphonic acid (RA CAS no 75 -75 -2). In a typical assay, Methane sulphonic acid was applied to two plates containing the pol A⁺organism and two plates containing the pol A^-organism. The plates were then incubated for 16 hrs and the zones of inhibition were measured. Methane sulphonic acid did not cause growth inhibition due to DNA damage in two strains ofEscherichia coliexposed to 50 µL/plate without S9 metabolic activation and hence is negative foe gene mutation in vitro.

In a study by Szybalski ( Annals New York Academy of Sciences, 1958), Gene mutation toxicity study was performed to determine the mutagenic nature of Methane sulphonic acid. Genetic toxicity test was performed on strain of Escherichia coli (strain Sd-4-73) by paper disk method. Paper-disk method was performed to check for the ability of E. coli Sd-4-73 to show reversion from streptomycin dependence to independence. Overnight culture of strain Sd-4-73 grown at 36°C in aerated nutrient broth containing 20 µg/ml of streptomycin was used as a inoculum. The culture was centrifuged and washed at least twice with saline or distilled water to remove the extraneous streptomycin, and was resuspended in saline to a concentration of approximately 10⁹cells/ml. 0.1-ml aliquot of this suspension was mixed with 2.5 ml of molten soft nutrient agar (0.7 per cent agar) and poured over a base of 20 ml of 1.5 per cent nutrient agar. After the soft layer was solidified, the mutagen was applied in form of small drops or crystal. Additional plates were prepared with small inocula (one fifth and one twenty-fifth of the original) so as not to miss the optimum cell density; the number of cells per plate was rather critical, the yield of mutant colonies being reduced either by crowding or by insufficient population size. After the soft agar layer had set, the mutagen, in the form of a microdrop of solution (0.01 to 0.025 ml.) or a small crystal, was applied to a small filter-paper disk resting on the agar. To determine whether the substance was inhibitory for the assay organism at the concentration employed, the procedure was repeated on a nutrient agar plate containing 100 µg/ml of streptomycin and seeded with approximately 10⁷bacteria. Mutagenicity was manifested as a zone of streptomycin- independent mutant colonies around a filter-paper disk saturated with the mutagenic agent and resting on the surface of streptomycin-free nutrient agar seeded heavily with a streptomycin-dependent parental population. Methane sulphonic aciddid not induce mutation from streptomycin dependence to independence in Escherichia coli (strain Sd-4-73) and hence it is not likely to classify as a gene mutant in vitro.

Based on the data available for the target chemical and its read across, 2-amino-5-[(4-amino-3-sulfonatophenyl) (3-sulfocyclohexa-2,5-dien-1-ylidene) methyl]-3-methylbenzenesulfonate does not exhibit gene mutation in vitro. Hence the test material is not likely to classify as a gene mutant as per the criteria mentioned in CLP regulation.

Justification for classification or non-classification

Based on the data available for the target chemical and its read across, 2-amino-5-[(4-amino-3-sulfonatophenyl) (3-sulfocyclohexa-2,5-dien-1-ylidene) methyl]-3-methylbenzenesulfonate does not exhibit gene mutation in vitro. Hence the test material is not likely to classify as a gene mutant as per the criteria mentioned in CLP regulation.