Registration Dossier

Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Study period:
16/01/2002-18/01/2002
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
comparable to guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2002
Report Date:
2002

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Specific details on test material used for the study:
Preparation : By mixing 300 mg of the test substance with 6 mL of distilled water, the highest concentration (5000 µg / 0.1 µL / plate) was prepared. This solution was serially diluted to half its concentration to prepare the others concentrations.

Method

Target gene:
Not specified
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A
Metabolic activation:
with and without
Metabolic activation system:
S9mix (from Sprague dawley rats + 9 mL of distilled water contaiing S9 cofactors)
Test concentrations with justification for top dose:
312.5 ; 625 ; 1250 ; 2500 ; 5000 µg/0.1 µL/plate
Vehicle / solvent:
distilled water
Controls
Untreated negative controls:
yes
Remarks:
Distilled water
Negative solvent / vehicle controls:
not specified
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
9-aminoacridine
sodium azide
other: 2-(2-furyk)-3-(5-nitro-2furyl) acrylamide (AF2) and 2-aminoanthracène (2-AA)
Details on test system and experimental conditions:
Culture media :
- Nutrient broth
Nutrient broth No.2 was dissolved in distilled water to prepare a 2.5% culture medium and 20mL of the medium added in each Erlenmeyer flask was sterilized for 15 min. at 121°C.
- Minimum glucose agar medium
TESMEDIA AN (Wako Pure Chemical Industries) was used. Each plate was marked by writing an ID number on the top of the rid.
- Top agar
For four Salmonella typhimurium strains, 10-part of 0.6 % agar containing 0.5 % Na i, 1-part of 0.5 mM D-biotin and. 1-part of 0.5 mM L-histidine were mixed.
For Escherichia coli; 10-part of agar and 1-part of 0.5mM L-tryptophan were mixed
Evaluation criteria:
Assessment
Positive reaction (+) : The number of revertant colonied per plate was more than twice that for the negative control group and this increased number of revertant colonies was reproducible and dose-dependent.
Negative reaction (—) : Other reactions
Growth inhibition : The background lawn for the test substance group was clearly rougher or clearer compared to that of the negative control group.
Statistics:
Not specified

Results and discussion

Test resultsopen allclose all
Key result
Species / strain:
S. typhimurium TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not applicable
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:
not specified
Vehicle controls validity:
not applicable
Untreated negative controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 98
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not applicable
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:
not specified
Vehicle controls validity:
not applicable
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Not specified

Applicant's summary and conclusion

Executive summary:

Based on these findings, it was concluded that under the conditions established for the present study, DIPOTASSIUM GLYCYRRHIZINATE was judged as non-mutagen.