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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2
Test concentrations with justification for top dose:
In phase A, Salmonella typhimurium TA100 was exposed to 5 different cocentrations of test substance (C1-C5), prepared with a 10 dilution factor, As cytotoxicity may vary in the presence of metabolic activation systems, the test was carried out in presence and in absence of S9 (-S9; +S9). The highest concentration (C1) was 5 mg/plate, the highest allowed in the test. The solution resulted dissolved.

In phase B, the 4 remaining bacteria strains were exposed to 5 different concentrations (C1-C5) of test substance prepared with a 10 dilution factor, in presence and in absence of a metabolic activation system (-S9; +S9). The concentrations were selected according to the preliminary cytotoxicity test. Since no cytotoxicity was observed at 5 mg.plate the highest concentration allowed in the assay, this solution was used as the first concentration (C1) to test in phase B (AMES test).
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
no
True negative controls:
no
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
9-aminoacridine
2-nitrofluorene
other: Sodium Azide; Nitrofurantoine; 4-Nitro-1,2-phenilendiammine

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
not valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
not valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1535
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
not valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
not valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Vehicle controls validity:
not valid
Untreated negative controls validity:
valid
Positive controls validity:
valid

Applicant's summary and conclusion

Conclusions:
Positive results from the bacterial reverse mutation test indicate that a substance induses point mutations by base substitutions or frameshifts in the genome of either Salminella typhimurium and.or Escherichia coli.
Negative results indicate that under the test conditions, the test substance is not mutagenic in the tested species.
On the basis of the results obtained, it can be concluded that, under the test conditions applied, the test item "Sargassum Extract powder" is considered not to be mutagenic.