[No public or meaningful name is available]

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

March 2008

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2008

Report date:

2008

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

Micromethod Ames's test

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Avena Sativa leaf/stem extract

IUPAC Name:

Avena Sativa leaf/stem extract

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

The test substance is a dry extract containing maltodextrine. This compound is not expected to interfere with the results of the test as it is an inert substance.

Method

Target gene:

His locus

Species / strain

Species / strain / cell type:

other: Salmonella typhimurium TA1537, TA98, TA100

Details on mammalian cell type (if applicable):

rfa mutation for all strains; pKM 101 ampicillin resistance plasmid for strains TA100 and TA 98

Additional strain / cell type characteristics:

DNA polymerase A deficient

Metabolic activation:

with and without

Metabolic activation system:

S9 fraction of rat liver

Test concentrations with justification for top dose:

0.29, 0.86, 2.57, 7.72, 23.15, 69.44, 208.33, 625, 1250, 2500 µg/plate
Solubility was the limiting factor for maximum dose.

Vehicle / solvent:

DMSO

Controls

Negative solvent / vehicle controls:

yes

True negative controls:

yes

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

other: 2-anthramine

Details on test system and experimental conditions:

Incubation during 48h.
Each dose is performed in triplicate, per strain and type of treatment.

Rationale for test conditions:

Reference to the guideline study

Evaluation criteria:

Mean number of spontaneous revertants per plate

Statistics:

Yes, method not specified

Results and discussion

Test results

Test results 1

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:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 3

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with

Genotoxicity:

positive

Remarks:

significant increase of revertants at 69.04 µg/plate but induction ratio of 3 was not reached

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 4

Species / strain:

S. typhimurium TA 100

Metabolic activation:

without

Genotoxicity:

ambiguous

Remarks:

increase in revertants at 625 to 2500 µg/plate but induction ratio of 2 not reached

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 5

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with

Genotoxicity:

positive

Remarks:

significant increase in revertants at 2500 µg/plate but induction ratio of 2 not reached

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Validity criteria were fulfilled.
Results on TA100, without metabolic activation at the three highest doses: statistically significant increase in the mean number of revertants in presence of test item. But induction ratio of 2 was not reached and the mean number of revertants were within the limits of historical data for negative control in the same experimental conditions. However, taking into account the absence of toxicity of test item at the doses tested, the clear dose-response relationship obseved and the fact that the maximum tested dose was limited by the solubility of test item, results were considered equivocal. To confirm or invalidate the mutagenicity of test item in this strain, an additional assay under the same experimental conditions but using a narrower range of doses (e.g. 3000-2500-2000-1500-1000-750-500-250) should be undertaken.

Remarks on result:

other: no biologically significant

Remarks:

No dose-response relationship

Applicant's summary and conclusion

Conclusions:

The test item S02542 provided by Institut de Recherche Pierre Fabre induced an equivocal result on Salmonella typhimurium strain TA100, in absence of metabolic activation, in a screening micromethod assay of the Ames's test without repetition.
In return, no mutagenic activity was observed in the Salmonella typhimurium strains TA1537 and TA98 in absence or in presence of metabolic activation system, or in strain TA100 in presence of metabolic activation.
An additional assay should be performed, under the same experimental conditions, in strain TA100 in absence of metabolic activation, using a narrower dose range between 3000 and 250 µg/mL.