Sodium bis[4-hydroxy-3-[(2-hydroxy-1-naphthyl)azo]-N-(3-methoxypropyl)benzenesulphonamidato(2-)]cobaltate(1-)

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The test item did not produce mutagenic effects in bacteria 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

Study period:

2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

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:

rat Liver S9-mix

Test concentrations with justification for top dose:

0; 33; 1 00; 333; 1 000; 2500; and 5000 µg/plate

Vehicle / solvent:

DMSO

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

methylmethanesulfonate

other: 4-nitro-o-phenylene-diamine (4-NOPD); 2-aminoanthracene (2-AA)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation); preincubation;

DURATION
- Preincubation period: 60 minutes
- Exposure duration:48 hours

NUMBER OF REPLICATIONS: 3

DETERMINATION OF CYTOTOXICITY
- Method: evaluation of background lawn

Evaluation criteria:

A test item is considered positive if a dose related increase in the number of revertants exceeding the threshold of twice or thrice the colony count of the corresponding solvent control is observed at more than one concentration. Furthermore, a biologically relevant and reproducible increase exceeding the threshold at one test concentration is considered as positive.
A test item producing neither a dose related increase in the number of revertants nor a biologically relevant positive response at any one of the test points is considered nonmutagenic in this system.
A biologically relevant response is described as follows:
An increase is considered relevant in the strains TA 98, TA 100, and WP2 uvrA the number of reversions will be at least twice as high and in the strains TA 1535 and TA 1537 at least three times higher as compared to the spontaneous reversion rate.
Also, a dose-dependent and reproducible increase in the number of revertants is regarded as an indication of possibly existing mutagenic potential of the test item regardless whether the highest dose induced the above described enhancement factors or not.

Statistics:

No statistical evaluation of the data is required.

Species / strain:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 5000µg/plate in experiment II

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

with S-9 Mix

 

	Revertants/plate
	mean from three plates
Concentration	TA 1535	TA 1535	TA 1537	TA 1537	TA 98	TA 98	TA 100	TA 100	WP2 uvrA	WP2 uvrA
µg/plate	I	II	I	II	I	II	I	II	I	II
Negative control	14	14	14	7	28	19	-	178	39	52
Solvent control	13	16	10	10	33	28	-	175	40	43
Positive control##	119	110	67	43	445	286	-	508	172	165
33	17	11	6	8	28	26	-	157	44	54
100	10	9	8	11	36	24	-	154	47	47
333	14	11	8	8	29	26	-	168	34	52
1000	11	9	9	9	47	35	-	212	50	53
2500	15	12	15	7	54	41	-	207	43	52
5000	8	6	0	2	17	32	-	197	26	50

 

## 2-aminoanthracene (2.5 µg/plate; 10.0 µg/plate in strain TA 102)

 

without S-9 Mix

 

 

	Revertants/plate
	mean from three plates
Concentration	TA 1535	TA 1535	TA 1537	TA 1537	TA 98	TA 98	TA 100	TA 100	WP2 uvrA	WP2 uvrA
µg/plate	I	II	I	II	I	II	I	II	I	II
Negative control	13	14	12	9	20	21	-	147	35	48
Solvent control	12	12	8	9	17	20	-	100	35	46
Positive control##	918	775	65	45	157	168	-	833	858	417
33	10	9	9	9	21	17	-	104	43	61
100	11	6	8	9	22	18	-	118	46	58
333	7	10	8	8	22	19	-	127	43	56
1000	9	9	8	8	24	21	-	123	39	53
2500	7	5	5	4	18	14	-	46	31	42
5000	2	4	0	2	4	11	-	30	23	38

 

##Sodium azide (10 µg/plate) strains TA 1535 and TA 100;

4-Nitro-o-phenylene-diamine (10 µg/plate) strains TA 1537 and TA 98;

Methyl-methane-sulfonate (1µL/plate) strain TA 102

Conclusions:

Interpretation of results (migrated information):
negative

The test item did not iduce gene muatations in bacteria with and without metabolic activation by rat liver S9.

Executive summary:

This study was performed to investigate the potential of the test item to induce gene mutations according to the plate incorporation test (experiment I) and the pre-incubation test (experiment II) using the Salmonella typhimurium strains TA 1535, TA 1537, TA 98, and TA 100, and the Escherichia coli strain WP2 uvrA.

The assay was performed in two independent experiments both with and without liver microsomal activation.

Each concentration, including the controls, was tested in triplicate.

The test item was tested at the following concentrations:

33; 1 00; 333; 1 000; 2500; and 5000 µg/plate

Some of the plates showed reduced background growth at high concentrations with and without metabolic activation in experiment II. No visible reduction of the background growth was observed with and without metabolic activation in experiment I. Distinct toxic effects, evident as a reduction in the number of revertants, occurred in almost all of the strains at 2500 and 5000 µg/plate.

No substantial and reproducible increase in revertant colony numbers of any of the five tester strains was observed following treatment with the test item at any dose level, neither in the presence nor absence of metabolic activation (S9 mix). There was also no tendency of higher mutation rates with increasing concentrations in the range below the generally acknowledged border of biological relevance.

Appropriate reference mutagens were used as positive controls and showed a distinct increase of induced revertant colonies

In conclusion, it can be stated that during the described mutagenicity test and under the experimental conditions reported, the test item did not induce gene mutations by base pair changes or frameshifts in the genome of the strains used.

Therefore, the test item is considered to be non-mutagenic in this Salmonella typhimurium and Escherichia coli reverse mutation assay.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Mode of Action Analysis / Human Relevance Framework

not applicable

Justification for classification or non-classification

No classification

No adverse effects were detected.