Methyl stearate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

25 Mar - 02 Apr 1992

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP guideline study with acceptable restrictions (purity of test item not stated, incomplete strain selection, E. coli strain is missing)

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Version / remarks:

adopted in 1983

Deviations:

yes

Remarks:

purity of test item not given; incomplete strain selection since E. coli strain is missing

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Methyl stearate

EC Number:

203-990-4

EC Name:

Methyl stearate

Cas Number:

112-61-8

Molecular formula:

C19H38O2

IUPAC Name:

methyl stearate

Details on test material:

- Name of test material (as cited in study report): Stearinsäuremethylester
- Physical state: solid, white
- Substance type: Fatty acid methyl ester
- Analytical purity: not given
- Storage condition of test material: room temperature

Method

Target gene:

his operon

Species / strain

Species / strain 1

Species / strain / cell type:

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

Additional strain / cell type characteristics:

other: rfa-; uvrB- (R+ for TA 98 and TA 100)

Species / strain 2

Species / strain / cell type:

S. typhimurium TA 1538

Additional strain / cell type characteristics:

other: rfa-; uvrB-

Metabolic activation:

with and without

Metabolic activation system:

cofactor supplemented post-mitochondrial fraction (S9 mix) prepared from the livers of rats treated with Aroclor 1254.

Test concentrations with justification for top dose:

8, 40, 200, 1000 and 5000 µg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: acetone
To prevent toxic effects of the solvent medium the stock solution of the test substance was doubled and 50 µL/plate instead of 100 µL/plate was introduced in the test.

Controls

Untreated negative controls:

yes

Remarks:

culture media

Negative solvent / vehicle controls:

yes

Remarks:

Acetone

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2 µg/plate sodium azide (TA100 and 1535, -S9), 80 µg/plate 9-aminoacridine (TA1537, -S9), 40 µg/plate 4-nitro-o-phenylendiamine (TA98 and 1538, -S9), 2.5 µg/plate 2-aminoanthracene (TA1535, 1537, +S9), 5 µg/plate 2-aminoanthracene (TA98, 100, 1538, +S9)

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Exposure duration: 48 h
- Expression time (cells in growth medium): 48 h

NUMBER OF REPLICATIONS: 3

DETERMINATION OF CYTOTOXICITY
- Method: Inspection of the bacterial background lawn

OTHER: The spontaneous mutation rates of each tester strain were within the characteristic spontaneous mutation rates.
Two experiments were performed including negative and positive controls in the absence and presence of an S9 metabolising system.

Evaluation criteria:

The test material may be considered positive in this test system if the following criteria are met: For the test item to be considered mutagenic, two-fold (or more) increases in mean revertant numbers must be observed at two consecutive dose levels or at the highest practicable dose level only. In addition, there must be evidence of a dose-response relationship showing increasing numbers of mutant colonies with increasing dose levels. All cultures must demonstrate the characteristic mean number of spontaneous revertants in the vehicle controls.

Statistics:

Mean and standard deviation were calculated.

Results and discussion

Test results

Test results 1

Species / strain:

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

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 5000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Test results 2

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

at 5000 µg/plate

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

COMPARISON WITH HISTORICAL CONTROL DATA: Yes
ADDITIONAL INFORMATION ON CYTOTOXICITY: Slight cytotoxicity and precipitation were observed at 5000 µg/plate.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Mutagenicity on bacteria - experiment I 

With or without S9-Mix	Test substance concentration (μg/plate)	Mean number of revertant colonies per plate (average of 3 plates)
		TA 1535	TA100	TA1537	TA1538	TA98
	Buffer	14	132	12	9	21
-	Solvent (Acetone)	15	133	10	13	26
-	8	14	111	12	7	25
-	40	10	119	9	9	28
-	200	20	121	10	11	21
-	1000	15	115	7	11	16
	5000	7	115	10	8	16
Positive controls - S9	Name	SA	SA	9AA	4ND	4ND
	Concentrations (μg/plate)	2	2	80	40	40
	Number of colonies/plate	590	659	771	2408	1813
+	Buffer	16	158	11	28	35
+	Solvent (Acetone)	17	153	7	32	41
+	8	12	141	10	32	35
+	40	15	139	8	25	27
	200	17	156	12	38	37
+	1000	15	121	8	25	35
+	5000	8	96	10	27	22
Positive controls + S9	Name	2AA	2AA	2AA	2AA	2AA
	Concentrations (μg/plate)	2.5	5	2.5	5	5
	Number of colonies/plate	112	1532	137	1146	1555

9AA = 9-Aminoacridine

2AA = 2-Aminoanthracene

SA = Sodium Acide

4ND = 4-Nitro-o-phenylendiamine

  

Table 2: Mutagenicity on bacteria - experiment II

With or without S9-Mix	Test substance concentration (μg/plate)	Mean number of revertant colonies per plate (average of 3 plates)
		TA 1535	TA100	TA1537	TA1538	TA98
	Buffer	20	133	10	6	26
-	Solvent (Acetone)	20	123	12	6	16
-	8	13	126	11	7	29
-	40	15	121	9	11	23
-	200	16	128	8	11	27
-	1000	14	137	11	9	24
	5000	13	141	9	10	25
Positive controls - S9	Name	SA	SA	9AA	4ND	4ND
	Concentrations (μg/plate)	2	2	80	40	40
	Number of colonies/plate	465	652	978	2055	1816
+	Buffer	18	125	11	23	42
+	Solvent (Acetone)	23	102	7	23	35
+	8	22	125	4	33	41
+	40	16	125	4	26	30
	200	22	125	6	28	41
+	1000	18	122	7	38	39
+	5000	16	78	6	27	41
Positive controls + S9	Name	2AA	2AA	2AA	2AA	2AA
	Concentrations (μg/plate)	2.5	5	2.5	5	5
	Number of colonies/plate	104	1127	137	738	831

9AA = 9-Aminoacridine

2AA = 2-Aminoanthracene

SA = Sodium Acide

4ND = 4-Nitro-o-phenylendiamine

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative