Cysteine hydrochloride

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:

in or before 1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented study. However the short comings are: no GLP, purity not given although ch ecked, description of applied test substance concentration is not given.

Data source

Reference

Reference Type:

publication

Title:

Primary Mutagenicity Screening of Food Additives Currently Used in Japan

Author:

Ishidate M, Sofuni T, Yoshikawa K, Hayashi M, Nohmi T, Sawada M, Matsuoka A

Year:

1984

Bibliographic source:

Fd Chem. Toxic. 22: 623-636

Materials and methods

Principles of method if other than guideline:

reverse mutation assays using TA 2637, TA 92, TA 1535, TA 100, TA 1537, TA 94 and TA 98 strains
of Salmonella typhimurium according to Ames et al. 1975

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

L-Cysteine Hydrochloride Monohydrate

Cas Number:

175.63

Molecular formula:

C3H7NO2S·HCl·H2O

IUPAC Name:

L-Cysteine Hydrochloride Monohydrate

Test material form:

solid: granular

Method

Species / strain

Species / strain / cell type:

other: Salmonella typhimurium strains TA92, TA1535, TA100, TA1537, TA94 and TA98 with and without S9 activation. Additionally the substance was tested with TA 2637.

Metabolic activation:

with and without

Metabolic activation system:

The liver microsome fraction (S-9) was prepared from the liver of Fischer rats (Charles River Japan
Co.) pretreated 5 days before with polychlorinated biphenyls.

Test concentrations with justification for top dose:

duplicate plates for each of six different concentrations. However concentrations not stated for the
strains which gave negative results.

Vehicle / solvent:

phosphate buffer

Controls

Negative solvent / vehicle controls:

yes

Remarks:

phosphate buffer was used as solvent

Details on test system and experimental conditions:

DURATION
- Preincubation period: 20 min at 37°C before plating
- Duplicate plates were used for each of six different concentrations of the sample
- Exposure duration: 2 days at 37°C.
- Number of revertant (his+) colonies was scored.
- Result was found positive if number of colonies was twice the number in the control/solvent control.

Results and discussion

Remarks on result:

other: Positive response in 2 out of 6 tested strains: 291/plate at 1.0 mg/plate in TA100 with S-9 mix; 598/plate in TA2637 at 10.0 mg/plate with S-9 mix; 601/plate at 2.0 mg/plate in TA2637 without S-9 mix.

Applicant's summary and conclusion

Conclusions:

L-Cystein monohydrochloride was tested in the Salmonella/microsome test (Ames-test) with 5 strains, TA92, TA1535, TA 100, TA 1537, Ta 98, TA 94 and TA 2637, up to concentrations of 20 mg per plate. L-Cystein was assessed positive.
L-Cysteine monohydrochloride was assessed as positive in the Ames test.

Executive summary:

L-Cysteine monohydrochloride was tested in the Salmonella/microsome test (Ames-test) with 5 strains, TA92, TA1535, TA 100, TA 1537, Ta 98, TA 94 and TA 2637, up to concentrations of 20 mg per plate.
L-Cysteine monohydrochloride induced 401 revertants (110 in controls) at 10.0 mg/plate in TA 100 with S-9 mix, and induced 613 revertants (15 in control) at 10.0 mg/plate and 616 revertants (15 in control) at 2.0 mg/plate in TA 2637 with and without S-9 mix respectively.
L-Cysteine monohydrochloride was assessed as positive under the conditions of this Ames test.