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Toxicological information

Developmental toxicity / teratogenicity

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Administrative data

Endpoint:
developmental toxicity
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
1977
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
documentation insufficient for assessment
Remarks:
Original reference in Japanese language

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1977

Materials and methods

Principles of method if other than guideline:
Prenatal developmental toxicity study: Groups of pregnant Japanese white rabbits were administered orally with d-limonene at dose levels of 250, 500 and 1000 mg/kg bw/day for 13 days from Day 6 to 18 of gestation and evaluated for teratogenicity.
GLP compliance:
not specified
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): d-limonene; d-p-mentha-1,8-diene

Test animals

Species:
rabbit
Strain:
other: Japanese white
Details on test animals and environmental conditions:
no data

Administration / exposure

Route of administration:
oral: unspecified
Vehicle:
not specified
Details on exposure:
no data
Analytical verification of doses or concentrations:
not specified
Details on analytical verification of doses or concentrations:
no data
Details on mating procedure:
No data
Duration of treatment / exposure:
13 days (gestation Day 6-18)
Frequency of treatment:
Once daily
Duration of test:
Gestatation Day 0 to postnatal Day 49
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/kg bw/day
Dose / conc.:
250 mg/kg bw/day
Dose / conc.:
500 mg/kg bw/day
Dose / conc.:
1 000 mg/kg bw/day
No. of animals per sex per dose:
10 (in 0-500 mg/kg bw/day groups) or 18 (in 1000 mg/kg bw/day group) pregnant females
Control animals:
yes
Details on study design:
no data

Examinations

Maternal examinations:
CAGE SIDE OBSERVATIONS: No data

General behaviour observed, but no data regarding the frequency of observation

BODY WEIGHT: Yes
- Time schedule for examinations: daily

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
mean daily food consumption by treatment group is reported

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data


POST-MORTEM EXAMINATIONS: No data

OTHER:
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: No data
Examinations included: Number of implantations, number of resorptions and foetus bodyweight and placental weight
Fetal examinations:
- External examinations: Yes: about 90% per litter
- Visceral examinations: Yes: about 90% per litter
- Skeletal examinations: Yes: about 90% per litter
Statistics:
statistical significance difference of effects from controls were calculated at 5% level.
Indices:
no data
Historical control data:
no data

Results and discussion

Results: maternal animals

Maternal developmental toxicity

Details on maternal toxic effects:
Maternal toxic effects:yes

Details on maternal toxic effects:
Treatment with the highest dose level (1000 mg/kg) of d-limonene resulted in death of dams with less than 40% mortality. The significant decrease of body- weight gain and food consumption were temporarily observed in dams given 500 and 1000 mg/kg of d-limonene, but no anomalies were observed in the general behaviour of dams given 250 and 500 mg/kg of d-limonene during the gestation.

Effect levels (maternal animals)

Key result
Dose descriptor:
NOAEL
Effect level:
250 mg/kg bw/day (actual dose received)
Based on:
test mat.
Basis for effect level:
other: maternal toxicity

Maternal abnormalities

Key result
Abnormalities:
no effects observed

Results (fetuses)

External malformations:
no effects observed
Skeletal malformations:
effects observed, non-treatment-related
Description (incidence and severity):
- Visceral and skeletal examinations revealed some anormalies such as incomplete lobulation of the lungs, enlargement of the foramen ovale and retarded ossification of the middle phalanx of fore limbs in addition to the 5th sternebrae. These did not appear to be dose-dependent and restored to normal during the postnatal development.
Visceral malformations:
effects observed, non-treatment-related
Description (incidence and severity):
- Visceral and skeletal examinations revealed some anormalies such as incomplete lobulation of the lungs, enlargement of the foramen ovale and retarded ossification of the middle phalanx of fore limbs in addition to the 5th sternebrae. These did not appear to be dose-dependent and restored to normal during the postnatal development.
Other effects:
effects observed, non-treatment-related
Description (incidence and severity):
- Other non specific anormalies involved the lumber ribs in fetuses and offsprings, formation of the accessory ossification center of the 5th sternebrae in offsprings and the atrial septal defect detected in only 2 fetuses of a litter from dams treated with 250 mg/kg bw/day of d-limonene.
Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:no effects

Effect levels (fetuses)

Key result
Dose descriptor:
NOAEL
Effect level:
> 1 000 mg/kg bw/day (actual dose received)
Based on:
test mat.
Basis for effect level:
other: fetotoxicity

Fetal abnormalities

Key result
Abnormalities:
no effects observed

Overall developmental toxicity

Key result
Developmental effects observed:
no

Any other information on results incl. tables

Table 1: Effect of d-limonene on prenatal development of rabbit fetuses

Dose (mg/kg bw)

Control

250

500

1000

No. of pregnant animals

10

10

10

18

No. of dead clams

0

0

0

6

(%)

 

 

 

33

No. of examined clams

10

10

10

10

No. of implantations

96

94

85

91

(mean ± S.E.)

9.50 ± 0.25

9.40 ± 0.21

8.50 ± 0.33

9.10 ± 0.25

No. of resorbed fetuses

5

4

4

8

No. of dead fetuses

3

5

0

3

No. of live fetuses

88

85

81

80

Sex ratio (Male/Female)

0.73 (37/51)

1.13 (45/50)

0.62 (31/50)

1.11 (38/42)

Fetus body weight (g)

 

 

 

 

Male (mean ± S.E.)

44.39 ± 1.33

48.09 ± 1.07 *

44.76 ± 1.51

43.22 ± 0.96

Female (mean ± S.E.)

45.64 ± 1.00

47.45 ± 1.08

46.14 ± 1.21

45.13 ± 1.10

Placental weight (g)

 

 

 

 

Male (mean ± S.E.)

5.76 ± 0.17

5.84 ± 0.17

5.95 ± 0.29

5.77 ± 0.19

Female (mean ± S.E.)

5.87 ± 0.19

5.70 ± 0.15

6.16 ± 0.18

5.87 ± 0.23

* Significantly different from the control at 5% level

Table 2: Prenatal examinations of rabbit fetuses

Dose (mg/kg bw)

Control

250

500

1000

External examination

 

 

 

 

No. of examined fetuses

91

90

81

83

No. of malforrned fetuses

0

0

0

0

Visceral examination

 

 

 

 

No. of examined fetuses

88

85

81

80

No. of malformed fetuses

 

 

 

 

Atrial septal defect (%)

0

2 (2.4)

0

0

No. of minor abnormality

 

 

 

 

Incomplete lobulation of lungs (%)

11 (12.5)

16 (18.8)

19 (23.5)

19 (23.8)

Enlargement of foramen ovale (%)

2 (2.3)

2 (2.4)

5 (6.2)

4 (5.0)

Skeletal examination

 

 

 

 

No. of examined fetuses

86

87

81

80

No. of malformed fetuses

0

0

0

0

No. of variation

 

 

 

 

Left lumbar rib (%)

18 (20.9)

26 (29.9)

14 (17.3)

25 (31.3)

Right lumbar rib (%)

16 (18.6)

22 (25.3)

14 (17.3)

22( 27.5)

Ossification pattern

 

 

 

 

Retarded ossification of 5th sternebrae (%)

11 (12.8)

14 (16.1)

8 (9.9)

18 (22.5)

Retarded ossification of middle phalanx of fore limbs (%)

2 (2.3)

3 (3.4)

0

6 (7.4)

Table 3: Absolute organ weights of rabbit offsprings

 

Male

Female

 

Control

250

500

1000

Control

250

500

1000

No. of offsprings

13

12

8

13

10

13

16

9

Final body weight (g)

893.0 ± 45.3

1021.2 ± 45.4 **

931.9 ± 55.5

957.3 ± 52.4

1005.5 ± 53.7

1093.1 ± 46.6

860.0 ± 31.6 *

1071.7 ± 58.1

Liver (g)

36.49 ± 2.52

45.08 ± 1.52 *

38.67 ± 3.10

34.91 ± 2.76

41.79 ± 3.39

13.95 ± 3.18

34.68 ± 1.90

48.30 ± 6.14

Lungs (g)

5.53 ± 0.35

6.25 ± 0.26

5.98 ± 0.36

5.46 ± 0.18

5.91 ± 0.25

5.94 ± 0.28

5.72 ± 0.18

5.93 ± 0.45

Heart (g)

2.63 ± 0.17

3.50 ± 0.16 **

2.86 ± 0.17

3.04 ± 0.19

3.19 ± 0.17

3.38 ± 0.21

2.72 ± 0.12 *

3.34 ± 0.20

Spleen (g)

0.71 ± 0.05

0.77 ± 0.04

0.71 ± 0.08

0.81 ± 0.04

0.64 ± 0.06

0.74 ± 0.05

0.74 ± 0.04

0.78 ± 0.07

Thymus (g)

2.31 ± 0.20

2.51 ± 0.23

2.11 ± 0.38

1.96 ± 0.11

2.40 ± 0.30

2.77 ± 0.19

1.671.14 *

2.36 ± 0.31

Kidneys (g)

7.67 ± 0.42

9.80 ± 0.46 **

8.29 ± 0.29

8.58 ± 0.52

8.82 ± 0.46

8.40 ± 0.30

7.86 ± 0.37

9.56 ± 0.55

Thyroids (mg)

75.89 ± 8.35

102.68 ± 4.18*

86.74 ± 10.97

80.93 ± 7.41

82.78 ± 8.00

89.90 ± 4.11

75.75 ± 5.43

96.30 ± 9.67

Adrenals (mg)

69.65 ± 6.02

9.1.93 ± 1.06 **

78.79 ± 5.89

71.36 ± 6.00

82.23 ± 4.37

94.24 ± 5.07

87.64 ± 4.18

105.39 ± 15.11

Testes or Ovaries

(mg)

180.42 ± 17.15

272.86 ± 16.46 **

185.62 ± 23.78

162.84 ± 20.59

46.31 ± 7.90

46.10 ± 2.80

43.53 ± 2.69

47.77 ± 3.59

* Significantly different from the control at 5% level

** Significantly different from the control at 1% level

Table 4: Relative organ weights per 100 g of rabbit offsprings

 

Male

Female

 

Control

250

500

1000

Control

250

500

1000

No. of offsprings

13

12

8

13

10

13

16

9

Final body weight (g)

893.0 ± 45.3

1021.2 ± 45.4 **

931.9 ± 55.5

957.3 ± 52.4

1005.5 ± 53.7

1093.1 ± 46.6

860.0 ± 31.6 *

1071.7 ± 58.1

Liver (g/100 g)

4.08 ± 0.25

3.99 ± 0.22 *

4.16 ± 0.26

3.52 ± 0.10

4.25 ± 0.17

4.03 ± 0.21

4.02 ± 0.16

4.04 ± 0.32

Lungs (g/100 g)

0.61 ± 0.03

0.55 ± 0.03

0.65 ± 0.04

0.58 ± 0.03

0.62 ± 0.02

0.55 ± 0.02 *

0.67 ± 0.03

0.51 ± 0.02 **

Heart (g/100 g)

0.29 ± 0.01

0.31 ± 0.01

0.31 ± 0.01

0.31 ± 0.02

0.33 ± 0.01

0.31 ± 0.01

0.32 ± 0.01

0.29 ± 0.01 *

Spleen (g/100 g)

0.08 ± 0.01

0.07 ± 0.01

0.08 ± 0.01

0.08 ± 0

0.07 ± 0.01

0.07 ± 0.01

0.09 ± 0

0.07 ± 0.01

Thymus (g/100 g)

0.25 ± 0.02

0.22 ± 0.02

0.25 ± 0.03

0.20 ± 0.01 *

0.24 ± 0.03

0.25 ± 0.01

0.195 ± 0.01

0.20 ± 0.02

Kidneys (g/100 g)

0.85 ± 0.04

0.86 ± 0.04

0.90 ± 0.03

0.88 ± 0.02

0.91 ± 0.02

0.80 ± 0.01

0.91 ± 0.01

0.83 ± 0.03 *

Thyroids (mg/100 g)

8.21 ± 0.69

9.10 ± 0.51

9.21 ± 0.87

8.18 ± 0.42

8.40 ± 0.56

8.41 ± 0.45

8.81 ± 0.57

8.13 ± 0.41

Adrenals (mg/100 g)

7.82 ± 0.60

8.37 ± 0.40

8.58 ± 0.77

7.18 ± 0.28

8.61 ± 0.51

8.79 ± 0.57

9.15 ± 0.42

9.04 ± 0.14

Testes or Ovaries

(mg/100 g)

23.68 ± 1.31

19.68 ± 0.94 *

19.48 ± 1.69

16.35 ± 1.56

5.15 ± 1.19

4.33 ± 0.32

5.19 ± 0.43

3.84 ± 0.32

* Significantly different from the control at 5% level

** Significantly different from the control at 1% level

Table 5: Effects of d-limonene on gross differentiations of rabbit offsprings

 

Control

250

500

1000

No. of examined offsprings

23

25

24

22

Days of gross differentiation after birth

Opening of the ear-shell

 

 

 

 

6th day (%)

0

0

1 (4.2)

0

7th day (%)

23 (100)

25 (100)

23 (95.8)

22 (100)

Coating with the hair

 

2nd day (%)

7 (30.4)

0

0

0

3rd day (%)

16 (69.6)

25 (100)

24 (100)

22 (100)

Odontiasis

 

At birth (%)

23 (100)

25 (100)

24 (100)

22 (100)

Opening of the eyelids

 

9th day (%)

0

0

0

3 (13.6)

10th day (%)

11 (47.8)

4 (16.0)

13 (54.2)

5 (22.7)

11th day (%)

4 (17.4)

15 (60.0)

10 (41.7)

12 (54.5)

12th day (%)

3 (13.0)

5 (20.0)

1 (4.2)

2 (9.1)

13th day (%)

5 (21.7)

1 (4.0)

0

0

Table 6: Effects of d-limonene on postnatal development of rabbit offsprings

 

Control

250

500

1000

No of dams

3

3

3

3

No. of still-birth (Male/Female)

1 (1/0)

0

0

1 (0/1)

No. of offsprings (Male/Female)

At birth

28 (15/13)

27 (14/13)

26 (8/18)

27 (15/12)

1st week

28 (15/13)

27 (14/13)

25 (8/17)

26 (14/12)

2nd week

26 (14/12)

27 (14/13)

25 (8/17)

26 (14/12)

3rd week

24 (14/10)

27 (14/13)

25 (8/17)

25 (14/11)

4th week

23 (13/10)

26 (13/13)

25 (8/17)

22 (13/ 9)

5th week

23 (13/10)

25 (12/13)

25 (8/17)

22 (13/ 9)

6th week

23 (13/10)

25 (12/13)

25 (8/17)

22 (13/ 9)

7th week

23 (13/10)

25 (12/13)

24 (8/16)

22 (13/ 9)

Weanling rate (%)

79.3 (81.2/76.9)

92.6 (85.7/100)

92.3 (100/88.9)

78.6 (86.7/69.2)

Table 7: Postnatal examinations of rabbit offsprings

 

Control

250

500

1000

No. of dams

3

3

3

3

No. of examined offsprings

23

25

24

22

Sensory function

Normal

Normal

Normal

Normal

External examination

No. of malformed offsprings

0

0

0

0

Visceral examination

No. of malformed offsprings

0

0

0

0

No. of minor abnormality

Incomplete lobulation of lungs (%)

2 (8.7)

1 (4.0)

0

0

Accessory spleen (%)

2 (8.7)

0

0

0

Protrusion of gall bladder (%)

1 (4.3)

1 (4.0)

0

0

Skeletal examination

No. of malformed offsprings

0

0

0

0

No. of variation

Left lumbar rib (%)

4 (17.4)

4 (16.0)

4 (16.7)

4 (18.2)

Right lumbar rib (%)

2 (8.7)

6 (24.0)

6 (25.0)

4 (18.2)

Translocation of caudal vertebrae (%)

1 (4.3)

0

1 (4.2)

0

Ossification pattern

Retarded ossification of 5th sternebrae (%)

0

2 (8.0)

0

1 (4.5)

Accessory ossification center of 5th sternebrae (%)

1 (4.3)

2 (8.0)

0

3 (13.6)

Applicant's summary and conclusion

Conclusions:
Under the test conditions, d-limonene was not teratogenic in rabbit fetuses and the NOAEL for fetal toxicity was considered to be greater than 1000 mg/kg bw/day. The NOAEL for maternal toxicity was considered to be 250 mg/kg bw/day based on the decreased bodyweight gain.
Executive summary:

In a prenatal developmental toxicity study, d-limonene was administered orally to groups of pregnant Japanese white rabbits at dose levels of 250, 500 and 1000 mg/kg bw/day for 13 days from Day 6 to 18 of gestation. Food consumption and bodyweights of pregnant rabbits were recorded during organogenesis. Caesarean sections were performed and the number of dead, live or resorbed fetuses, sex ratio and number of implantation sites were recorded. Fetuses were weighed and examined for external, visceral and skeletal malformations.

 

Treatment with the highest dose level (1000 mg/kg bw/day) of d-limonene resulted in death of 6/18 dams (33% mortality). The significant decrease of bodyweight gain and food consumption were temporarily observed in dams given 500 and 1000 mg/kg bw/day of d-limonene, but no anormalies were observed in the general behavior of dams given 250 and 500 mg/kg bw/day of d-limonene during the gestation. External examination of fetuses showed no anormalies. Visceral and skeletal examinations revealed some anormalies such as incomplete lobulation of the lungs, enlargement of the foramen ovale and retarded ossification of the middle phalanx of fore limbs in addition to the 5th sternebrae. These did not appear to be dose-dependent and restored to normal during the postnatal development. Other non specific anormalies involved the lumber ribs in fetuses and offsprings, formation of the accessory ossification center of the 5th sternebrae in offsprings and the atrial septal defect detected in only 2 fetuses of a litter from dams treated with 250 mg/kg bw/day of d-limonene.

 

Under the test conditions, d-limonene was not teratogenic in rabbit fetuses and the NOAEL for fetal toxicity was considered to be greater than 1000 mg/kg bw/day. The NOAEL for maternal toxicity was considered to be 250 mg/kg bw/day based on the decreased bodyweight gain.