(R)-thiazolidine-4-carboxylic acid

Genetic toxicity: in vitro

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

Report date:

2020

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

(R)-thiazolidine-4-carboxylic acid

EC Number:

252-106-3

EC Name:

(R)-thiazolidine-4-carboxylic acid

Cas Number:

34592-47-7

Molecular formula:

C4H7NO2S

IUPAC Name:

(R)-thiazolidine-4-carboxylic acid

Test material form:

solid: particulate/powder

Method

Target gene:

histidine

Species / strain

Species / strain 1

Species / strain / cell type:

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

Species / strain 2

Species / strain / cell type:

E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

liver S9 fraction

Test concentrations with justification for top dose:

On the basis of the results obtained in the preliminary toxicity test, in Main Assay I, using
the plate incorporation method, the test item was assayed with all tester strains at the
following dose levels: 5000, 2500, 1250, 625 and 313 µg/plate.

Details on test system and experimental conditions:

A preliminary toxicity test was undertaken in order to select the concentrations of the test
item to be used in the Main Assays. In this test a wide range of dose levels of the test item,
set at half-log intervals, were used. Treatments were performed both in the absence and
presence of S9 metabolism using the plate incorporation method; a single plate was used
at each test point and positive controls were not included. Toxicity was assessed on the
basis of a decline in the number of spontaneous revertants, a thinning of the background
lawn or a microcolony formation.

Two Main Assays were performed including negative and positive controls in the absence
and presence of an S9 metabolising system. Three replicate plates were used at each test
point.
In addition, plates were prepared to check the sterility of the test item suspensions and
the S9 mix and dilutions of the bacterial cultures were plated on nutrient agar plates to
establish the number of bacteria in the cultures.
The Main Assay I was performed using a plate-incorporation method. The components
of the assay (the tester strain bacteria, the test item and S9 mix or phosphate buffer) were
added to molten overlay agar and vortexed. The mixture was then poured onto the surface
of a minimal medium agar plate and allowed to solidify prior to incubation.

Results and discussion

Test results

Test results 1

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Test results 2

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Test results 3

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Test results 4

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Test results 5

Species / strain:

E. coli WP2

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Additional information on results:

No toxicity was observed at any dose level with any tester strain, in the absence or presence
of S9 metabolic activation.
As no relevant increase in revertant numbers was observed at any concentration tested, a
Main Assay II was performed using the same concentrations and including a pre-incubation
step for all treatments. No toxicity or relevant increase in the number of revertant colonies
was observed in the pre-incubation assay, at any dose level, with any tester strain/treatment
condition combinations.
No precipitation of the test item was observed in any experiment, at any dose level, in the
absence or presence of S9 metabolic activation.
The test item did not induce two-fold increases in the number of revertant colonies in the
plate incorporation or pre-incubation assay, at any dose level, in any tester strain, in the
absence or presence of S9 metabolism.

Applicant's summary and conclusion

Conclusions:

It is concluded that the test item L(-)-Thiazolidine-4-carboxylic acid (TCA) does not induce
reverse mutation in Salmonella typhimurium or Escherichia coli in the absence or presence
of S9 metabolism, under the reported experimental conditions.