Plant Sterols

Genetic toxicity: in vivo

Administrative data

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

2001

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to an appropriate OECD test guideline. It was not compliant with GLP.

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2002

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

not specified

Type of assay:

micronucleus assay

Test material

Test material information

Constituent 1

Reference substance name:

phytosterol esters

IUPAC Name:

phytosterol esters

Details on test material:

- Name of test material (as cited in study report): phytosterol esters


- Other: Sterol profile composition of sample (%, w/w)

Cholesterol 0.3
Brassicasterol 3.0
Campesterol 28.1
Stigmasterol 18.7
β -Sitosterol 45.5
'others' 6.4

Phytosterols (ex-Roche) were sourced from a variety of common edible vegetable oil distillates (mainly soya bean). The phytosterols were then re-esterified with fatty acids from sunflower oils to phytosterol esters, which were suspended in corn oil.

Test animals

Species:

rat

Strain:

other: Crl:HanWist

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Ltd
- Age at study initiation: 6-7 weeks
- Weight at study initiation: no data
- Assigned to test groups randomly: [no/yes, under following basis: ]
- Fasting period before study: no data
- Housing: no data
- Diet (e.g. ad libitum): no data
- Water (e.g. ad libitum): no data
- Acclimation period:

ENVIRONMENTAL CONDITIONS
- Temperature (°C): no data
- Humidity (%): no data
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): no data

IN-LIFE DATES: From: To:

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

- Vehicle(s)/solvent(s) used: corn oil
- Justification for choice of solvent/vehicle: none given
- Concentration of test material in vehicle: 10 ml/kg
- Amount of vehicle (if gavage or dermal):

Duration of treatment / exposure:

24 hours

Frequency of treatment:

The compound and the solvent controls were administered twice at 24 hour intervals, the positive control was administered 24 hours before sacrifice.

Post exposure period:

The animals were sacrificed 24 hours after dosing and bone marrow slides prepared from a single femur.

Doses / concentrations

Remarks:

Doses / Concentrations:
500, 1000 and 2000 mg/kg/day
Basis:

No. of animals per sex per dose:

8 per dose group

Control animals:

yes, concurrent vehicle

Positive control(s):

- cyclophosphamide
- Route of administration: gavage
- Doses / concentrations: 80 mg/kg

Examinations

Tissues and cell types examined:

Femoral bone marrow

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: based on LD50.

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields): PE and solvent control dose groups were treated twice at 24 hour intervals. Positive controls were dosed once for 24 hours.

DETAILS OF SLIDE PREPARATION: Bone marrow slides were prepared from a single femur and stained in 12.5 µg/ml acridine orange.

METHOD OF ANALYSIS: Toxicity was assessed from the relative proportion of PCEs and NCEs per 1000 cells. The incidence of micronuclei was assessed in 2000 PCEs per animal

Evaluation criteria:

Evidence of mutagenic activity was defined by a statistically and biologically significant increase in micronuclei.

Statistics:

Chi-squared analysis

Results and discussion

Test results

Sex:

male

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Any other information on results incl. tables

Bone marrow micronucleus in rats

 

Treatment group (mg/kg/day)	Mean ratio PCE/NCE	Group mean frequency of micronucleated PCE ± SD (per 1000 cells)
Solvent control	0.90	0.25±(0.38)
500	0.92	0.12±(0.23)
1000	1.35	0.25±(0.38)
2000	1.09	0.12±(0.23)
Positive control	0.40	3.13±(2.56)

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): negative
Phytosterol esters has been tested for its potential clastogenic effect in a bone marrow micronucleus assay, in a study which was conducted according to OECD 474 (1997), not in compliance with GLP. No evidence of test substance-related increase in the frequency of micronucleated polychromatic erythrocytes was obtained after oral gavage administration of 500, 1000 and 2000 mg/kg bw phytosterol esters, administered twice 24 hours apart. No evidence of a test substance related increase in toxicity to bone marrow was observed. Appropriate positive and vehicle controls were included and gave acceptable results. It is concluded that the test substance is negative for induction of micronuclei (is not clastogenic) under the conditions of the test.