3',6'-bis(diethylamino)spiro[isobenzofuran-1(3H),9'-[9H]xanthene]-3-one

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from peer reviewed publication

Data source

Reference

Reference Type:

publication

Title:

Evaluation of Laser Dye Mutagenicity Using the Ames/Salmonella Microsome Test

Author:

Barbara J.Y. Wuebbles and James S. Felton

Year:

1985

Bibliographic source:

Environmental Mutagenesis 7511-522 (1985)

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Method as described by Ames et al 1975

Principles of method if other than guideline:

Gene mutation study was performed to evaluate the mutagenic nature of the test compound Rhodamine B using Salmonella typhimurium strain TA1538, TA98 and TA100

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

9-(2-carboxyphenyl)-3,6-bis(diethylamino)xanthylium chloride

EC Number:

201-383-9

EC Name:

9-(2-carboxyphenyl)-3,6-bis(diethylamino)xanthylium chloride

Cas Number:

81-88-9

Molecular formula:

C28H31N2O3.Cl

IUPAC Name:

9-(2-carboxyphenyl)-3,6-bis(diethylamino)xanthenium chloride

Test material form:

solid

Specific details on test material used for the study:

- Name of test material: Rhodamine B
- Molecular formula: C28H31N2O3Cl
- Molecular weight: 479.017 g/mol
- Substance type: Organic
- Physical state: No data available
- Purity: No data available
- Impurities (identity and concentrations): No data available

Method

Target gene:

Histidine

Species / strain

Species / strain / cell type:

S. typhimurium, other: TA1538 and TA100

Details on mammalian cell type (if applicable):

Not applicable

Additional strain / cell type characteristics:

not specified

Cytokinesis block (if used):

No data

Metabolic activation:

with and without

Metabolic activation system:

S9 protein was obtained from the liver of Aroclor-induced male Sprague-Dawley rats.

Test concentrations with justification for top dose:

0.1 mg/plate or 1 mg/plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO
- Justification for choice of solvent/vehicle: No data available

Controls

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

not specified

Positive control substance:

not specified

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

DURATION
- Preincubation period: No data available
- Exposure duration: 2 days (48 hrs)
- Expression time (cells in growth medium): 2 days (48 hrs)
- Selection time (if incubation with a selection agent): No data available
- Fixation time (start of exposure up to fixation or harvest of cells): No data available

SELECTION AGENT (mutation assays): No data available
SPINDLE INHIBITOR (cytogenetic assays): No data available
STAIN (for cytogenetic assays): No data available

NUMBER OF REPLICATIONS: Duplicate

NUMBER OF CELLS EVALUATED: No data available

DETERMINATION OF CYTOTOXICITY
- Method: mitotic index; cloning efficiency; relative total growth; other: No data available

OTHER EXAMINATIONS: No data available
- Determination of polyploidy: No data available
- Determination of endoreplication: No data available
- Other: No data available

OTHER: No data available

Rationale for test conditions:

No data

Evaluation criteria:

A sample was judged mutagenic if it produced greater than twice the spontaneous background colonies at more than one dose or at the highest dose tested.

Statistics:

To estimate mutagenic potency (revertant /µg) from linear dose-response curves, the method of Moore and Felton was used

Results and discussion

Test results

Species / strain:

S. typhimurium, other: TA1538 and TA100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

not specified

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: No data available
- Effects of osmolality: No data available
- Evaporation from medium: No data available
- Water solubility: No data available
- Precipitation: No data available
- Other confounding effects: No data available

RANGE-FINDING/SCREENING STUDIES: Spot test was performed with and without activation using the Salmonella typhimurium strains TA1538, TA98 and TA100. The spot test results were inconclusive. The dyes were then screened at 0.1 mg/plate and 1 mg/plate.

COMPARISON WITH HISTORICAL CONTROL DATA: No data available

ADDITIONAL INFORMATION ON CYTOTOXICITY: No data available

Applicant's summary and conclusion

Conclusions:

Rhodamine B does not induce gene toxicity in the Salmonella typhimurium strains TA1538, TA98 and TA100. Hence it is negative for gene mutation.

Executive summary:

Gene mutation study was performed to evaluate the mutagenic nature of Rhodamin B using Salmonella typhimurium strain TA1538 and TA100.

 

Bacteria were grown overnight in Oxoid nutrient broth, then refrigerated at 4-5^OC for a few hours before use. 0.1 ml of bacterial culture was added to 2 ml of 45°C molten top agar containing 0.01 mg histidine HCI and 0.012 mg biotin/ml, followed by the test sample in ≤0.2 ml DMSO. Finally, 0.5 ml of sodium phosphate buffer, pH 7.4 (no activation), or 0.5 ml of Aroclor-induced rat S9 mixture was added, and the mixture was poured on minimal glucose agar plates. Histidine revertant colonies were counted on a Biotran II automated colony counter after 2-day incubation at 37°C.

 

A sample was judged mutagenic if it produced greater than twice the spontaneous background colonies at more than one dose or at the highest dose tested.

 

In the above mentioned study, Rhodamine B failed to induce gene mutation in theSalmonella typhimuriumstrains TA1538 and TA100 with and without metabolic activation.

 

Hence,Rhodamine B, is not likely to be a gene mutant in vitro.