Eugenol

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Study period:

1983

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Study design appears to follow latest OECD guideline 408 (1998) with deviations (biochemical and hematological analysis not performed or not reported; details on the frequency of exposure and time-points of observations were not reported; and no statistical analysis provided).

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1983

Report date:

1983

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

yes

Remarks:

biochemical and hematological analysis not performed or not reported, details on the frequency of exposure and time-points of observations were not reported; and no statistical analysis provided

Principles of method if other than guideline:

Groups of rats received diets containing 0, 800, 1,500, 3,000, 6,000, or 12,500 ppm eugenol (eq to 80, 150, 300, 600 and 1250 mg/kg bw/d) for 13 weeks.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Eugenol

EC Number:

202-589-1

EC Name:

Eugenol

Cas Number:

97-53-0

Molecular formula:

C10H12O2

IUPAC Name:

2-methoxy-4-(prop-2-en-1-yl)phenol

Test material form:

other: Eugenol was added to the meal through a liquid dispersion bar

Details on test material:

- Name of test material (as cited in study report): eugenol
- Physical state: Liquid
- Analytical purity: >99%
- Lot/batch No.: Lot No. 36483
- Stability under test conditions: Test article in feed is stable for 2 weeks at temperatures as high as 45°C
- Storage condition of test material: Stored at 20 to 24°C

Test animals

Species:

rat

Strain:

other: F344/N

Sex:

male/female

Details on test animals or test system and environmental conditions:

The male and female F344/N rats were obtained from the NCI Frederick Cancer Research Center (Frederick, Maryland). The F344/N rats used in these studies were produced under strict barrier conditions.
Upon receipt, the animals were isolated for 7-8 days and examined for the presence of parasites or other diseases. The animals were assigned randomly by species and sex to cages and then the cages were assigned randomly to dosed and control groups. The rats were 6-7 weeks old at the beginning of each study.
The rats were housed five per cage in suspended solid-bottom polycarbonate cages covered with Reemay® spun-bonded polyester filters and Dupont style #2024 filters. Hardwood chip bedding was changed twice per week, and feed hoppers (stainless steel) were changed and washed once per week. Cages were washed twice per week in a tunnel cage dish washer at 82°C.
An automatic watering system supplied tap water.
Feed was available ad libitum.
Animal rooms were maintained at 21-23°C and humidity was 30-50%.
Incoming air was filtered through fiberglass roughing filters.
Room air was changed 15 times per hour.
Fluorescent lighting was provided 12 hours per day.

Administration / exposure

Route of administration:

oral: feed

Vehicle:

unchanged (no vehicle)

Details on oral exposure:

Test diets were prepared by mixing Wayne Lab Blox meal and eugenol in a twin-shell laboratory blender for 15 minutes. Eugenol was added to the meal through a liquid dispersion bar. The test diets were stored at 5°C for 1 week followed by no more than 1 week at 21 to 23°C.

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Dosed feed samples were analyzed. No further details available.

Duration of treatment / exposure:

90 days

Frequency of treatment:

Not reported but assumed to be once per day for 90 days

Doses / concentrations

Remarks:

Doses / Concentrations:
800, 1,500, 3,000, 6,000, or 12,500 ppm eugenol (equivalent to 80, 150, 300, 600, and 1,250 mg/kg body weight, respectively).
Basis:
nominal in diet

No. of animals per sex per dose:

10 males and 10 females/dose group

Control animals:

yes, plain diet

Details on study design:

Groups of 10 male rats and 10 female rats received diets containing 0, 800, 1,500, 3,000, 6,000, or 12,500 ppm eugenol for 13 weeks.

Positive control:

Not reported.

Examinations

Observations and examinations performed and frequency:

Observations for clinical signs or mortality were made twice daily and animals were weighed weekly. No further details available.

Sacrifice and pathology:

At the end of the 91-day study, survivors were killed, necropsies were performed on all animals, and tissues from the controls and the highest dose group were taken for histopathologic analysis.

Statistics:

No data

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Description (incidence and severity):

No deaths reported (no data on clinical signs)

Mortality:

no mortality observed

Description (incidence):

No deaths reported (no data on clinical signs)

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Organ weight findings including organ / body weight ratios:

not specified

Gross pathological findings:

no effects observed

Histopathological findings: non-neoplastic:

no effects observed

Histopathological findings: neoplastic:

not specified

Details on results:

CLINICAL SIGNS AND MORTALITY - No deaths occurred among the rats tested with eugenol in their diets.
BODY WEIGHT AND WEIGHT GAIN - Final absolute body weights were 10% less than control for male rats and 6% less than control for female rats, both in the 12,500 ppm dose group when compared to controls.
FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study) - Not reported
FOOD EFFICIENCY - Not reported
OPHTHALMOSCOPIC EXAMINATION - Not reported
HAEMATOLOGY - Not reported
CLINICAL CHEMISTRY - Not reported
URINALYSIS - Not reported
NEUROBEHAVIOUR - Not reported
ORGAN WEIGHTS - Not reported
GROSS PATHOLOGY and HISTOPATHOLOGY: NON-NEOPLASTIC - No compound-related gross or histopathologic effects were observed.

Effect levels

1

Dose descriptor:

NOAEL

Effect level:

ca. 600 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: slight body weight decrease at 1250 mg/kg bw/day

2

Dose descriptor:

LOAEL

Effect level:

ca. 1 250 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

other: see 'Remark'

3

Dose descriptor:

NOAEL

Effect level:

>= 1 250 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

female

Basis for effect level:

other: 6% lower final body weight observed in female rats administered 12500 ppm eugenol (equivalent to 1250 mg/kg body weight) compared to control females. Expert judgment.

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

None

Applicant's summary and conclusion

Conclusions:

In the absence of mortality, gross pathology and histopathology changes in both sexes, the NOAEL in rats was determined based on slight body weight decrease and a slight body weight changes at 6000 and 12500 ppm (equivalent to 600 or 1250 mg eugenol/kg bw/day) in males and females, respectively. The final NOAEL was determined at 600 mg/kg bw/d in males and at or above 1250 mg/kg bw/d in females.
 

Executive summary:

The potential toxicity of repeated exposure to eugenol was assessed in a 90 -day oral toxicology study in rat. The dietary administration of eugenol at concentrations of 0 (control), 800, 1,500, 3,000, 6,000, or 12,500 ppm daily to male and female F344/N rats for 90 days resulted in a small (i.e.,10%) decrease in body weights in high-dose males together with 12.4% reduction of body weight gain considered as slight treatment-related effect when compared with Controls. Very slight decrease body weights in the high-dose females (6%) accompanied to a reduction body weight gain of 5.9% were not considered as adverse effect. No other statistically significant, test article-related effects were noted in body weights. No effects were noted in mortality, gross pathology, and histopathology in either sex. Based on the body weight findings, the NOAELs in male and female rats was determined to be 6,000 or 12,500 ppm [approximately equivalent to 600 or 1,250 mg Eugenol/kg body weight/day (U.S. FDA, 1993)], respectively. 

 

Reference:

U.S. FDA. Priority Based Assessment of Food Additives (PAFA) Database. Washington (DC): Food and Drug Administration (FDA), Center for Food Safety and Applied Nutrition (CFSAN); 1993.