Pyridine-2,6-dicarboxylic acid

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

The test item Dipicolinic acid (DPA) showed no increase in the number of revertants in all bacteria strains in both experiments.

All negative and all strain-specific positive control values were within the laboratory his-torical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly.

Based on the results of this study it is concluded that Dipicolinic acid (DPA) is not muta-genic in the Salmonella typhimurium test strains TA97a, TA98, TA100, TA102 and TA1535 in the absence and presence of metabolic activation under the experimental conditions in the present study.

In all experiments, no precipitation of the test item Dipicolinic acid (DPA) was observed at any of the tested concentrations up to 5000 µg/plate.

In the first experiment, the test item caused no cytotoxicity towards all bacteria strains

In the second experiment, the test item caused cytotoxicity towards all bacteria strains in the highest concentrations (5000 µg/plate).

The confirmation tests of the genotype did not show any irregularities. The control of the titre was above the demanded value of 109 bacteria/mL.

All of the means of all replicates of the spontaneous revertants (in negative and solvent controls) were within the range of the historical data of the test facility. All numbers of re-vertant colonies of the positive controls were within the range of the historical data of the laboratory (historical data of the laboratory chapter 15, page 39) and were increased in comparison with the negative controls, which demonstrated the mutagenic potential of the diagnostic mutagens.

Since all criteria for acceptability have been met, the study is considered valid

Link to relevant study records

Reference

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

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

Target gene:

Mutation
Name
hisD6610
hisD3052
hisG46
hisG428
uvrB
rfa
pKM101
pAQ1

Species / strain / cell type:

S. typhimurium TA 97

Additional strain / cell type characteristics:

not specified

Species / strain / cell type:

S. typhimurium TA 98

Additional strain / cell type characteristics:

not specified

Species / strain / cell type:

S. typhimurium TA 100

Additional strain / cell type characteristics:

not specified

Species / strain / cell type:

S. typhimurium TA 102

Additional strain / cell type characteristics:

not specified

Species / strain / cell type:

S. typhimurium TA 1535

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9-Miix

Test concentrations with justification for top dose:

In a non-GLP pre-test, the solubility of the test item was tested in a concentration of 50 g/L in demineralized water, dimethyl sulfoxide (DMSO) and ethanol.
DMSO was chosen as vehicle, because the test item was sufficiently soluble, and this solvent does not have any effects on the viability of the bacteria or the number of sponta-neous revertants in the tested concentrations.
On the day of the start of the first and the second experiment, a stock solution containing 50 g/L of the test item in DMSO was prepared. The test item solution was not sterile filtrat-ed before use.
The stock solution was used to prepare the geometric series of the concentrations to be tested. The following nominal concentrations were prepared for the first experiment:
5000 µg/plate, 1500 µg/plate, 500 µg/plate, 150 µg/plate and 50 µg/plate.
The following nominal concentrations were prepared for the second experiment:
5000 µg/plate, 2500 µg/plate, 1250 µg/plate, 625 µg/plate, 313 µg/plate and 156 µg/plate.

Vehicle / solvent:

DMSO

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

sodium azide

benzo(a)pyrene

other: 4-Nitro-1,2-phenylene Diamine and Amino-Anthracene

Evaluation criteria:

The colonies were counted visually and the numbers were recorded. A spreadsheet soft-ware (Microsoft Excel®) was used to calculate mean values and standard deviations of each treatment, solvent control and positive control.
The mean values and standard deviations of each threefold determination was calculated as well as the increase factor f(l) of revertant induction (mean revertants divided by mean spontaneous revertants) of the test item solutions and the positive controls. Additionally, the absolute number of revertants (Rev. Abs.) (mean revertants minus mean spontaneous revertants) was given.
A substance is considered to have mutagenic potential, if a reproducible increase of re-vertant colonies per plate exceeding an increase factor of 2 in at least one strain can be observed. A concentration-related increase over the range tested is also taken as a sign of mutagenic activity.

Key result

Species / strain:

S. typhimurium TA 97

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: the test item caused cytotoxicity towards all bacteria strains in the highest concentrations (5000 µg/plate)

Vehicle controls validity:

valid

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:

other: the test item caused cytotoxicity towards all bacteria strains in the highest concentrations (5000 µg/plate)

Vehicle controls validity:

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:

other: the test item caused cytotoxicity towards all bacteria strains in the highest concentrations (5000 µg/plate)

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 102

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: the test item caused cytotoxicity towards all bacteria strains in the highest concentrations (5000 µg/plate)

Vehicle controls validity:

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:

other: the test item caused cytotoxicity towards all bacteria strains in the highest concentrations (5000 µg/plate)

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Conclusions:

The test item Dipicolinic acid (DPA) showed no increase in the number of revertants in all bacteria strains in both experiments.
All negative and all strain-specific positive control values were within the laboratory historical control data ranges indicating that the test conditions were adequate and that the metabolic activation system functioned properly.
Based on the results of this study it is concluded that Dipicolinic acid (DPA) is not mutagenic in the Salmonella typhimurium test strains TA97a, TA98, TA100, TA102 and TA1535 in the absence and presence of metabolic activation under the experimental conditions in the present study.
In all experiments, no precipitation of the test item Dipicolinic acid (DPA) was observed at any of the tested concentrations up to 5000 µg/plate.
In the first experiment, the test item caused no cytotoxicity towards all bacteria strains
In the second experiment, the test item caused cytotoxicity towards all bacteria strains in the highest concentrations (5000 µg/plate).
The confirmation tests of the genotype did not show any irregularities. The control of the titre was above the demanded value of 109 bacteria/mL.
All of the means of all replicates of the spontaneous revertants (in negative and solvent controls) were within the range of the historical data of the test facility. All numbers of revertant colonies of the positive controls were within the range of the historical data of the laboratory (historical data of the laboratory chapter 15, page 39) and were increased in comparison with the negative controls, which demonstrated the mutagenic potential of the diagnostic mutagens.
Since all criteria for acceptability have been met, the study is considered valid.

Executive summary:

Two valid experiments were performed.

 

The study procedures described in this report were based on the most recent OECD and EC guidelines.

The test item Dipicolinic acid (DPA) was tested in the Salmonella typhimurium reverse mutation assay with five strains of Salmonella typhimurium (TA97a, TA98, TA100, TA102 and TA1535).

The test was performed in two experiments in the presence and absence of metabolic activation, with +S9 standing for presence of metabolic activation, and –S9 standing for absence of metabolic activation.

 

In the first experiment,the test item (dissolved in DMSO) was tested up to concentrations of 5000 µg/plate in the absence and presence of S9-mix in the strains TA97a, TA98, TA100, TA102 and TA1535 using the plate incorporation method.

The test item showed no precipitates on the plates at any of the concentrations.

The bacterial background lawn was not reduced at any of the concentrations and no relevant decrease in the number of revertants was observed in all bacteria strains. The test itemshowed no signs of toxicity towards the bacteria strains in both the absence and presence of metabolic activation.

The results of this experiment showed that none of the tested concentrations showed a significant increase in the number of revertants in all tested strains, in the presence and the absence of metabolic activation.

 

Based on the first experiment,the test item was tested up to concentrations of 5000  µg/plate in the absence and presence of S9-mix in all bacteria strains using the pre-incubation method.

The test item showed no precipitates on the plates at any of the concentrations.

In the highest concentration, no bacterial background lawn and no bacterial growth was observed.

The results of this experiments showed that the test item caused no increase in the number of revertants in all bacteria strains compared to the solvent control, in both the absence and presence of metabolic activation. The test item did not induce a dose-related increase in the number of revertants colonies in all strains, in the presence and absence of metabolic activation.

Based on the results of this study it is concluded that Dipicolinic acid (DPA) is not mutagenic in the Salmonella typhimuriumstrains TA97a, TA98, TA100, TA102 and TA1535 in the absence and presence of metabolic activation under the experimental conditions in this study.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on AMES Test Dipicolinic acid is not considered to warrant classification according to EU CLP (1272/2008) criteria.