Glutamic acid

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

June 30 - December 01, 2006

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Based on structural similarity, common metabolic pathway, environmental fate, comparable physico-chemical and (eco)toxicological properties, it is considered justified to use this study also for this substance. See the attached background document for detailed information. This study has been performed according to OECD and/or EC guidelines and according to GLP principles

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: Guidelines for Designation of Food Additives and for Revision of Standards for Use of Food Additives" (Japanese Ministry of Health and Welfare, Eika No. 29, March 22, 1996)

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: Guideline for Genotoxicity Tests on Drugs" (Pharmaceutical and Medical Safety Bureau, Japanese Ministry of Health and Welfare, Notification Iyakushin No. 1604, November 1, 1999)

Test guideline 3

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

Deviations:

no

Principles of method if other than guideline:

US Food and Drug Administration Redbook 2000: Toxicological Principles for the Safety Assessment of Food Ingredients IV.C.1.b. In vitro Mammalian Chromosomal Aberration Test" (July 7, 2000). The study conduct also complied with OECD 473.

GLP compliance:

yes

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

Sodium hydrogen glutamate

EC Number:

205-538-1

EC Name:

Sodium hydrogen glutamate

Cas Number:

142-47-2

Molecular formula:

C5H8NNaO4

IUPAC Name:

Sodium 2-amino-4-carboxybutanoate

Constituent 2

Reference substance name:

6106-04-3

Cas Number:

6106-04-3

IUPAC Name:

6106-04-3

Details on test material:

- Name of test material (as cited in study report): Monosodium L-glutamate monohydrate produced by a new method
- Substance type: hydrated form
- Physical state: White powder
- Stability under test conditions: stable
- Storage condition of test material: At room temperature under shading from light and well-closed conditions

Method

Species / strain

Species / strain / cell type:

mammalian cell line, other: Chinese Hamster Lung (CHL/IU)

Metabolic activation:

with and without

Metabolic activation system:

phenobarbital and 5,6-benzoflavone induced rat liver S9 mix

Test concentrations with justification for top dose:

Dose range finding/Growth inhibition test: without S9 mix: 0.030, 0.059, 0.12, 0.24, 0.48, 0.95 and 1.9 mg/ml (6h and 24h exposure; 24h fixation)
Dose range finding/Growth inhibition test: with S9 mix: 0.030, 0.059, 0.12, 0.24, 0.48, 0.95 and 1.9 mg/ml (6h exposure; 24h fixation)
Cytogenetic test: with and without S9 mix: 0.24, 0.48, 0.95 and 1.9 mg/ml (6h and 24 h exposure; 24h fixation)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: water for injection lP
- Justification for choice of solvent/vehicle: the test article was easily soluble in water (solubility: 740 mg/mL, 25°C).

Controls

Controls 1

Untreated negative controls:

yes

Remarks:

water for injection lP

Positive controls:

yes

Positive control substance:

mitomycin C

Remarks:

without S9 mix

Migrated to IUCLID6: in distilled water for injection JP

Controls 2

Positive controls:

yes

Positive control substance:

cyclophosphamide

Remarks:

with S9 mix

Migrated to IUCLID6: in distilled water for injection JP

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium
DURATION
- Preincubation period: 72h
- Exposure duration: 6h (with and without S9 mix), 24h (without S9 mix)
- Fixation time (start of exposure up to fixation or harvest of cells): 24h
SPINDLE INHIBITOR (cytogenetic assays): colcemid
STAIN (for cytogenetic assays): Giemsa solutions diluted with phosphate buffer
NUMBER OF REPLICATIONS: four in each group, duplicate in the positive control group
NUMBER OF CELLS EVALUATED: 200 metaphase chromosome spreads per culture
DETERMINATION OF CYTOTOXICITY
- Method: mitotic index of each culture was determined by counting the number of metaphases per 500
cells.
- Determination of polyploidy: yes
- Determination of endoreplication: no

Evaluation criteria:

Clastogenicity and polyploid induction of the test article were judged by considering the statistical analysis and biological significance.

Statistics:

The number of cells with structural chromosomal aberrations (excluding gaps) and polyploid cells in the treatment groups or the positive control
groups were statistically compared with the negative control group using Fisher's exact probability test (one-side, p<0.01). On the test systems in
which statistical significance was obtained, a dose-dependency of the induction of chromosomal aberrations was evaluated using the Cochran-
Armitage trend test (one-side, p<0.01).

Results and discussion

Test results

Species / strain:

mammalian cell line, other: Chinese Hamster Lung (CHL/IU)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: No precipitation was observed at the beginning and end of the treatment in the medium by the naked eye under any treatment
condition.
RANGE-FINDING/SCREENING STUDIES: No effects observed.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

The results obtained with the substance Monosodium glutamate are suitable for the regulatory purpose of REACH for the substance L-Glutamic acid:
There was no statistical significance of cells with structural chromosomal aberrations and polyploid cells at any treatment group.
Positive controls, MMC in the short-term without S9 mix and the continuous treatment and CP in the short-term treatment with S9 mix, significantly
induced structural chromosomal aberrations. It was therefore judged that this study adequately estimated the clastogenic potential of the test article.
Accordingly, it was concluded that Monosodium L-glutamate monohydrate produced by a new method did not induce chromosomal aberrations in
CHL/IU cells under the present test conditions.