Inulinase

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Inulinase was tested using the Ames assay.

Inulinase was not mutagenic when tested up to 9100 μg/mL in the presence and absence of metabolic activation in treat and plate assay.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19-02-1982 to 17-12-1982

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

no

Remarks:

Only assessed by quality assurance.

Type of assay:

bacterial reverse mutation assay

Target gene:

Histidine and tryptophan locus in the genome of five strains of bacteria

Species / strain / cell type:

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

Species / strain / cell type:

S. typhimurium TA 1538

Metabolic activation:

with and without

Metabolic activation system:

S-9 mix from Aroclor 1254-induced rat liver

Test concentrations with justification for top dose:

Preliminary test: No preliminary trials were carried out.
Six concentrations of the test item (30, 91, 303, 910, 3000, 9100 μg/mL)

Vehicle / solvent:

Vehicle for enzyme: Purified water.
Justification for choice of solvent/vehicle: Substance is water-soluble and any human exposure will be in aqueous solutions.
Solvent for the positive control: DMSO

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

2-nitrofluorene

sodium azide

other: 2-Aminoanthracene

Details on test system and experimental conditions:

METHOD OF APPLICATION: Preincubation in suspension, followed by plating on agar plates (treat and plate method).
- Cell density at seeding (if applicable): Not stated.

DURATION
- Exposure duration, pre-incubation: The incubation mixtures were incubated with shaking at 37 ± 1°C for 3 hours (treat and plate).
- Incubation time (selective incubation): 2 days

NUMBER OF REPLICATIONS: 3

DETERMINATION OF CYTOTOXICITY
- Method: Colony counting and colony growth

Evaluation criteria:

For S. typhimurium strains TA 1535, TA 1537 , TA 1538 and TA 98 at least a doubling of these mean control values was looked for at some concentration of the test substance, if a mutagenic effect was to be suspected. For S . typhimurium TA 100, a 1.5-fold increase over control value is indicative of a mutagenic effect.
A dose related response was also looked for, but at high dose levels this relationship may be inverted. Reasons for this inversion are, for example, (1) toxicity to the bacteria generally, (2) specific toxicity to the mutants and (3) (in the case of mutagens requiring activation by liver) inhibition of foreign compound metabolising enzymes.

Statistics:

N/A

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Water solubility: Yes
- Precipitation: Precipitation is a concentration limiting factor, but no issues were reported in this study.
- Definition of acceptable cells for analysis: Viability and gene type control.

HISTORICAL CONTROL DATA (with ranges, means and standard deviation and confidence interval (e.g. 95%)
- Negative (solvent/vehicle) historical control data: Yes.

Conclusions:

Inulinase was not mutagenic when tested up to 9100 μg/mL in the presence and absence of metabolic activation in treat and plate assay.

Executive summary:

Inulinase was tested for mutagenic activity in 5 strains of Salmonella typhimurium by treating the bacteria in liquid medium and removing inulinase prior to plating out for assay of revertant colonies (treat and plate). Inulinase concentrations tested were 30, 91, 303, 910, 3000, 9100 μg/mL. The experiment was conducted in the presence and absence of a liver preparation from male rats, pre-treated with Aroclor 1254, and the co-factors required for mixed-function oxidase activity (S-9 mix).

Inulinase was not mutagenic when tested up to 9100 μg/mL in the presence and absence of metabolic activation.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Justification for classification or non-classification

Not classified.