6,18-dihydrodinaphtho[2,3-i:2',3'-i']benzo[1,2-a:4,5-a']dicarbazole-5,7,12,17,19,24-hexone

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

FAT 46014/G and its metabolites did not induce gene mutations in the strains of S. typhimurium used.

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:

1993

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

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

Name: FAT 46014/G
Purity: 99.8 %

Target gene:

Histidine requiring genes of Salmonella strains

Species / strain / cell type:

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

Details on mammalian cell type (if applicable):

None

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

rat liver S9 mix

Test concentrations with justification for top dose:

Range in the cytotoxicity test
20.6 - 5000 µg/plate
Range in the mutagenicity test
61.7 - 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: Dimethylsulfoxide (Suspension)

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

sodium azide

Remarks:

without microsomal activation

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

mitomycin C

Remarks:

Without microsomal activation

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

2-nitrofluorene

Remarks:

Without microsomal activation

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

Remarks:

Without microsomal activation

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene

Remarks:

With microsomal activation

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

cyclophosphamide

Remarks:

With microsomal activation

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

Preliminary Toxicity/Ranqe-Findinq test
A toxicity test (check for reduction in the number of revertant colonies) was carried out with strain TA 100 without and with microsomal activation at six concentrations of the test substance and one negative control according to standard operating procedures of genetic toxicology. The highest concentration applied was 5000 µg/plate. The five lower concentrations decreased by a factor of 3. The plates were inverted and incubated for about 48 hours at 37 ± 1.5 °C in darkness Thereafter, they were evaluated by counting the colonies and determining the background lawn. One plate per test substance concentration, as well as each negative control was used.

Mutagenicity test
The mutagenicity test was performed with strains TA 98, TA 100, TA 102, TA 1535 and TA 1537 without and with microsomal activation according to standard operating procedures of genetic toxicology. Each of the five concentrations of the test substance, a negative and a positive control were tested, using three plates per test substance concentration as well as each positive and negative control with each tester strain. The highest concentration applied was 5000 µg/plate (because of lack of toxicity in the range finding test) and the four lower concentrations were each decreased by a factor of 3. The plates were inverted and incubated for about 48 hours at 37 ± 1.5 °C in darkness. Thereafter, they were evaluated by counting the number of colonies and determining the background lawn.

Evaluation criteria:

The test substance is considered to be mutagenic in this test system if the following conditions are met:
At least a reproducible meaningful increase of the mean number of revertants per plate above that of the negative control at any concentration for one or more of the following strains: S. typhimurium TA 98, TA 100, TA 102, TA 1535 and TA 1537. Generally a concentration-related effect should be demonstrable.

Statistics:

In deviation to the OECD guideline a statistical analysis was not performed. At present the use of statistical methods concerning this particular test system is not generally recommended. No appropriate statistical method is available

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

None

None

Conclusions:

Interpretation of results:
negative

Based on the results of these experiments and on standard evaluation criteria, it is concluded that FAT 46014/G and its metabolites did not induce gene mutations in the strains of S. typhimurium used.

Executive summary:

A study was performed to investigate the potential of FAT 46014/G to induce gene mutations in vitro gene mutation (Ames) test using the Salmonella typhimurium strains TA 1535, TA 1537, TA 9B, and TA 100. Cibanon Gelb 3R (FAT 46014/G) was tested for mutagenic effects without and with metabolic activation at five concentrations in the range of 61.7 to 5000 µg/plate. In the original experiment carried out without and with metabolic activation, none of the tested concentrations of Cibanon Gelb 3R (FAT 46014/G) led to an increase in the incidence of histidine-prototrophic mutants by comparison with the negative control. In the confirmatory experiment performed without metabolic activation, again, none of the tested concentrations of Cibanon Gelb 3R (FAT 46014/G) led to an increase in the incidence of histidine-prototrophic mutants by comparison with the negative control. In the mutagenicity tests without and with metabolic activation, normal background growth was observed. The number of revertant colonies was not reduced. The test substance exerted no toxic effect on the growth of the bacteria. Based on the results of these experiments and on standard evaluation criteria, it is concluded that Cibanon Gelb 3R (FAT 46014/G) and its metabolites did not induce gene mutations in the strains of S. typhimurium used.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

In a key study, FAT 46014/G was tested to detect the mutagenic potential in Ames test. FAT 46014/G was tested for mutagenic effects without and with metabolic activation at five concentrations in the range of 61.7 to 5000 µg/plate. In the experiment carried out with and without metabolic activation, none of the tested concentrations of FAT 46014/G led to an increase in the incidence of histidine-prototrophic mutants by comparison with the negative control. In the confirmatory experiment performed without metabolic activation, again, none of the tested concentrations of FAT 46014/G led to an increase in the incidence of histidine-prototrophic mutants by comparison with the negative control. In the mutagenicity tests without and with metabolic activation, normal background growth was observed. The number of revertant colonies was not reduced. The test substance exerted no toxic effect on the growth of the bacteria. In a supporting study, the substance FAT 46014/D was tested with the Salmonella typhimurium strains TA 1535, TA 1537, TA 98 and TA 100 at concentrations from 0.2 to 2000 ug per Petri dish both in the presence and absence of metabolic activation. No mutagenic effect was observed. In another supporting study, FAT 46014/E was tested for mutagenic effects on histidine-auxotrophic mutants of Salmonella typhimurium. The investigations were performed with the following concentrations of the trial substance with and without microsomal activation: 25, 75, 225, 675 and 2025 µg/0.1 ml. In the experiments performed with and without microsomal activation, comparison of the number of back-mutant colonies in the controls and the cultures treated with the various concentrations of FAT 46014/E revealed no marked deviations. No evidence of the induction of point mutations by FAT 46014/E or by the metabolites of the substance formed as a result of microsomal activation was detectable in the strains of S . typhimurium used in these experiments. Based on the results of these experiments and on standard evaluation criteria, it is concluded that FAT 46014/G and its metabolites did not induce gene mutations in the strains of S. typhimurium used.

Justification for selection of genetic toxicity endpoint
GLP guideline study

Justification for classification or non-classification

FAT 46014/G and its metabolites did not induce gene mutations in the strains of S. typhimurium used.