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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
study well documented, meets generally accepted scientific principles, acceptable for assessment
Remarks:
No reference to OECD guideline. Deviation from OECD guideline with the use of 4-o-Tolylazo-o-toluidine as positive control.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1975
Report Date:
1975

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
Only 4 strains of bacteria were used. Strain TA1538 was used and Strain TA98 was not. Positive controls deviate from those recommended in guidelines.
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Purity: 98.3%

Method

Species / strain
Species / strain / cell type:
S. typhimurium, other: strains TA100, TA1535, TA1537, TA1538
Metabolic activation:
with and without
Metabolic activation system:
Phenobarbitol-stimulated rat liver homogenate
Test concentrations with justification for top dose:
1, 10, 50, 100, 250, 500, 750, 1000 micrograms/plate. Test done in duplicate.
Controls
Untreated negative controls:
yes
Negative solvent / vehicle controls:
no
Positive controls:
yes
Positive control substance:
other: with activation-4-o-Tolylazo-o-toluidine, without activation-N-methyl-N'-nitro-N-nitrosoguanidine
Details on test system and experimental conditions:
METHOD:
In the absence of a metabolic activation system, approximately 5x10e8 bacteria were added to 2 mL of top agar (0.6% Difco agar, 0.6% NaCl, 0.050 mM of L-histidine, 0.05 mM of biotin). After the test chemical was added to the top agar, the solution was mixed and poured onto the surface of a minimal agar plate with Vogel-bonner E medium containing 1.5% agar and 2% glucose.

In the presence of the metabolic activation system, the metabolic system (0.25 mL) was added directly to the top agar immediately before it was poured over the minimal agar plate. The plates were incubated at 37°C for 40 hours. The number of histidine-positive revertant colonies on each plate was counted.

NUMBER OF REPLICATIONS: 2

Results and discussion

Test resultsopen allclose all
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
with
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1538
Metabolic activation:
without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium, other: TA1535, TA1537, TA100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Untreated negative controls validity:
valid
Positive controls validity:
valid

Any other information on results incl. tables

Metabolic Activation

Amount of Cmpd per Plate (ug)

TA100 his+ revertants/plate

TA1535 his+ revertants/plate

TA1537 his+ revertants/plate

TA1538 his+ revertants/plate

-

1

85

8

1

5

-

10

82

11

6

5

-

50

86

9

3

4

-

100

79

7

8

7

-

250

 

 

 

11

-

500

90

13

10

10

-

750

 

 

 

9

-

1000

97

9

25

10

 

 

 

 

 

 

+

1

87

11

10

13

+

10

95

9

9

16

+

50

82

10

7

18

+

100

98

10

6

19

+

250

 

 

 

42

+

500

104

10

9

88

+

750

 

 

 

99

+

1000

112

12

10

140

 

 

 

 

 

 

Negative control

 

 

 

 

 

-

0

72

11

5

9

+

0

84

11

6

15

 

 

 

 

 

 

4-o-Tolylazo-toluidine

 

 

 

 

 

-

25

 

 

 

10

+

25

 

 

 

195

 

 

 

 

 

 

N-methyl-N’-nitro-N-nitrosoguanidine

 

 

 

 

 

-

2

 

600

 

 

Applicant's summary and conclusion

Conclusions:
oPDA was mutagenic in strain TA1538 with activation but not mutagenic in this strain without metabolic activation. All other strains were negative for mutagenicity both with and without metabolic activation.
Executive summary:

oPDA was tested in four strains of Salmonella (TA1535, TA1537, TA1538, and TA100). All assays were conducted in the presence or absence of a phenobarbital-stimulated rat liver homogenate activation system. Dose levels tested included 1, 10, 50, 100, 250, 500, 750, and 1000 microgram/plate. oPDA was mutagenic in strain TA1538 with activation but not mutagenic in this strain without metabolic activation. All other strains were negative for mutagenicity both with and without metabolic activation.