Cinnamaldehyde

Endpoint summary

Description of key information

Repeated dose toxicity: Oral

The purpose of the study was to examine the relative toxicity of the test chemical in B6C3F1 mice when administered in corn oil by gavage. The test chemical was administered on a daily basis at dose concentration of 0, 656, 1310, 2620, 5250 or 10500 mg/kg/day for 14 days. No statistically significant differences in body weight, liver weight, spleen weight and kidney weight was observed. In addition, no statistically significant differences in organ:body weight ratios between surviving treated mice and control mice was observed. All mice from two highest dose group as well as all female mice and three male mice from the 656 mg/kg/day dose group died within the first 2 days of dosing. No clinical signs or gross lesions were observed in surviving mice and dead mice. Only a minimal to mild forestomach hyperplasia in both sexes and a minimal kidney nephropathy at doses of 1310 mg/kg/day and higher was shown. Hence, the no observed adverse effect level (NOAEL) of the test chemical was considered to be 656 mg/kg/day inB6C3F1 mice. The low observed adverse effect level (LOAEL) of the test chemical was considered to be 1310 mg/kg/day in B6C3F1 mice.

Repeated dose toxicity: Inhalation

The test chemical has very low vapor pressure (0.0289 mmHg at 25˚C), so the potential for the generation of inhalable vapours is very low. Also the normal conditions of use of this substance will not result in aerosols, particles or droplets of an inhalable size, so exposure to humans via the inhalatory route will be highly unlikely and therefore this end point was considered for waiver.

 

Repeated dose toxicity: Dermal

Repeated dose toxicity LOAEL (Lowest observed adverse effect level) of the test chemical to mouse by the dermal route was estimated at a dose concentration of 750 mg/kg bw/day. On the basis of this LOAEL value it is concluded that the test chemical was not toxic to rat by dermal route below the above mentioned dose.

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

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 journal

Qualifier:

according to guideline

Guideline:

other: Refer below principle

Principles of method if other than guideline:

Subacute toxicity of the test chemical was assessed by oral gavage in B6C3F1 mice in a 14-day study.

GLP compliance:

not specified

Limit test:

no

Species:

mouse

Strain:

B6C3F1

Sex:

male/female

Details on test animals or test system and environmental conditions:

Details on test animal
- Source: Charles River Laboratories
- Age at study initiation: 28 days
- Housing: Animals were housed individually in polycarbonate cages with hardwood shavings in a controlled environment.
- Diet (e.g. ad libitum): NIH-07 Rodent Chow
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS

- Temperature (°C): 72+2°F
- Humidity (%): 50 + 5%
- Photoperiod (hrs dark / hrs light): 12-hr light/dark cycle

Route of administration:

oral: gavage

Vehicle:

other: Mazola corn oil

Details on oral exposure:

Details on oral exposure
- Amount of vehicle (if gavage) : 10mL/Kg bw/day

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

14 days (2 weeks: 5 days/week for a total of 12 doses)

Frequency of treatment:

Daily

Remarks:

Doses / Concentrations:
0, 656, 1310, 2620, 5250 or 10500 mg/kg/day
Basis:
other: in corn oil

No. of animals per sex per dose:

Control: 5 mice
656 mg/kg/day: 5 mice
1310 mg/kg/day: 5 mice
2620 mg/kg/day: 5 mice
5250 mg/kg/day: 5 mice
10500 mg/kg/day: 5 mice

Control animals:

yes, concurrent vehicle

Details on study design:

The test chemical was administered to B6C3F1 mice in corn oil as vehicle on a daily basis by gavage route at dose concentration of 0, 656, 1310, 2620, 5250 or 10500 mg/kg/day for 14 days. Animals were humanely killed with CO2 when sacrificed. A complete autopsy was performed on all animals that died early, and at the termination of each study on all treated and control animals.

Positive control:

No data

Observations and examinations performed and frequency:

BODY WEIGHT: Yes
Body weights were determined.

ORGAN WEIGHT: Yes
Weight of the liver, right kidney and spleen were determined.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
Organs and tissues were examined for gross lesions and fixed in 10% neutral buffered formalin.

HISTOPATHOLOGY:
Complete histopathological examinations were carried out on all control animals, all early death animals, all animals in the highest dose group with at least 60% survivors and all animals in higher dose groups.

Other examinations:

OTHER:
A standard battery of 34 organs and tissues were trimmed, embedded in paraffin, sectioned, stained with hematoxylin and eosin, and examined microscopically. Organs identified as potential target organs (forestomach, testis, prostate, seminal vesicle, epididymis, uterus and ovary) were examined.
Organs identified as potential target organs (fore stomach, testis, prostate, seminal vesicle, epididymis, uterus, and ovary) were examined to a no-effect level in lower exposure groups

Statistics:

Statistics
Intergroup variations in all endpoints were analyzed by one-way analysis of variance. In cases where a statistically significant F-statistics in the ANOVA was observed, a multiple comparison procedure was used. The procedure of choice was the Ryan Einot Gabriel-Welsh multiple range test, which controls the type I experiment-wise error rate.

Clinical signs:

no effects observed

Description (incidence and severity):

No clinical signs were visible in these mice.

Mortality:

mortality observed, treatment-related

Description (incidence):

All mice gavaged withtest chemical at doses of 5250 and 10,500 mg/kg/day, as well as all female mice and three male mice dosed with 2620 mg/kg/day, died within the first 2 days of dosing. The cause of death could not be determined.

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No statistically significant differences were observed in body weight

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

not specified

Clinical biochemistry findings:

not specified

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

No statistically significant differences were observed in liver weight, spleen weight, kidney weight, or organ : body weight ratios between surviving treated mice and control mice.

Gross pathological findings:

no effects observed

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Minimal to mild fore stomach hyperplasia in both sexes and a minimal kidney nephropathy at doses of 1310 mg/kg/day was observed. The severity of the fore stomach hyperplasia was not related to dose or sex.

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Dose descriptor:

NOAEL

Effect level:

656 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Mortality, body weight, organ weight and histopathological examinations

Remarks on result:

not determinable due to absence of adverse toxic effects

Dose descriptor:

LOAEL

Effect level:

1 310 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Body weight, organ weight and histopathological examinations.

Remarks on result:

not determinable due to absence of adverse toxic effects

Critical effects observed:

not specified

Conclusions:

Based on all the available results, it was concluded that the no observed adverse effect level (NOAEL) of the test chemical was considered to be 656 mg/kg/day in B6C3F1 mice and the low observed adverse effect level (LOAEL) of the test chemical was considered to be 1310 mg/kg/day in B6C3F1 mice.

Executive summary:

The purpose of this study was to examine the relative toxicity of the test chemical in B6C3F1 mice when administered in corn oil by gavage. The test chemical was administered on a daily basis at dose concentration of 0, 656, 1310, 2620, 5250 or 10500 mg/kg/day for 14 days. No statistically significant differences in body weight, liver weight, spleen weight and kidney weight was observed. In addition, no statistically significant differences in organ:body weight ratios between surviving treated mice and control mice was observed. All mice from two highest dose group as well as all female mice and three male mice from the 2620 mg/kg/day dose group died within the first 2 days of dosing. No clinical signs or gross lesions were observed in surviving mice and dead mice. Only a minimal to mild forestomach hyperplasia in both sexes and a minimal kidney nephropathy at doses of 1310 mg/kg/day and higher was shown. Hence, the no observed adverse effect level (NOAEL) of the test chemical was considered to be 656 mg/kg/day inB6C3F1 mice. The low observed adverse effect level (LOAEL) of the test chemical was considered to be 1310 mg/kg/day in B6C3F1 mice.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

656 mg/kg bw/day

Study duration:

subacute

Species:

mouse

Quality of whole database:

The data is K2 peer reviewed publication

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records

Reference

Endpoint:

repeated dose toxicity: inhalation, other

Data waiving:

other justification

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Quality of whole database:

Waiver

Repeated dose toxicity: inhalation - local effects

Link to relevant study records

Reference

Endpoint:

repeated dose toxicity: inhalation, other

Data waiving:

other justification

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: dermal

Data waiving:

exposure considerations

Justification for data waiving:

a short-term toxicity study does not need to be conducted because exposure of humans via the dermal route in production and/or use is not likely as based on the provided thorough and rigorous exposure assessment

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Link to relevant study records

Reference

Endpoint:

short-term repeated dose toxicity: dermal

Data waiving:

exposure considerations

Justification for data waiving:

a short-term toxicity study does not need to be conducted because exposure of humans via the dermal route in production and/or use is not likely as based on the provided thorough and rigorous exposure assessment

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Data available for the test chemical was reviewed to determine the toxic nature of the test chemical. The studies are mentioned below:

 

Repeated dose toxicity: Oral

 

The purpose of the study was to examine the relative toxicity of the test chemical in B6C3F1 mice when administered in corn oil by gavage. The test chemical was administered on a daily basis at dose concentration of 0, 656, 1310, 2620, 5250 or 10500 mg/kg/day for 14 days. No statistically significant differences in body weight, liver weight, spleen weight and kidney weight was observed. In addition, no statistically significant differences in organ:body weight ratios between surviving treated mice and control mice was observed. All mice from two highest dose group as well as all female mice and three male mice from the 2620 mg/kg/day dose group died within the first 2 days of dosing. No clinical signs or gross lesions were observed in surviving mice and dead mice. Only a minimal to mild forestomach hyperplasia in both sexes and a minimal kidney nephropathy at doses of 1310 mg/kg/day and higher was shown. Hence, the no observed adverse effect level (NOAEL) of the test chemical was considered to be 656 mg/kg/day inB6C3F1 mice. The low observed adverse effect level (LOAEL) of the test chemical was considered to be 1310 mg/kg/day in B6C3F1 mice.

 

In the same study, the relative toxicity of the test chemical in in F344/N rats when administered in corn oil by gavage was studied. The test chemical was administered on a daily basis at dose concentration of 0, 235, 470, 940, 1880 & 3750 mg/kg/day for 14 days. There is slightly decrease in body weights of F344/N rats of both sexes in the 940 mg/kg/day group as compared to controls, although this decrease was statistically significant only for the females. No significant differences was observed in organ weights or organ weight:body weight ratios between surviving treated rats and controls. All the rats in last two dose groups died or during the first 7 days of dosing, however, no clinical signs and gross lesions were observed in surviving rats. Microscopic lesions included a minimal to moderate fore stomach hyperplasia in males at doses of 470 mg/kg/day and higher. Hence, The no observed adverse effect level (NOAEL) of the test chemical was considered to be 235 mg/kg/day inF344/N rats whereas the low observed effect level (LOAEL) was considered to be 470 mg/kg/day in F344/N rats.

 

The purpose of yet another study was to examine the relative toxicity of the test chemical in B6C3F1 mice when administered in microencapsulated form in feed. The test chemical was administered in feed diets containing 0, 0.625, 1.25, 2.5, 5 or 10% (w/w) per day in microcapsules for 21 days. There were no mortalities and no treatment-related clinical signs or gross lesions seen in any dose. However, there is a dose-related decrease in body weight and decreased absolute liver and kidney in treated mice as compared to control. Hyperplasia of the forestomach epithelium at highest dose (10%(w/w)) was characterized by a focal thickening of the stratified squamous epithelium, accompanied by hyperkeratosis. Hence, in a 21-day study, the no observed adverse effect level (NOAEL) was considered to be 1.25% (w/w) (1250 mg/kg) per day and the low observed adverse effect level (LOAEL) was considered to be 2.5% (w/w) (2500 mg/kg) per day mg/kg/day in B6C3F1 mice dosed with the test chemical.

 

The relative toxicity of the test chemical in F344/N rats when administered in microencapsulated form in dosed feed was also studied. The test chemical was administered in feed diets containing 0, 0.625, 1.25, 2.5, 5 or 10% (w/w) per day of CNMA in microcapsules for 14 days. No mortalities were observed in rats up to 10% (w/w) concentration in feed but a there was amarked dose related depression in body weight gain in rats of both sexes. Decreased absolute liver, kidney and spleen weights was observedwith slight decreased spleen:body weight ratio for male rats in the 10% (w/w) group, and a dose dependent decrease in food consumption was also observed. Gross lesions in both sexes were limited to a reduction in the size of reproductive organs and secondary sex glands (seminal vesicles & prostates of males & ovaries & uteri of females). In addition, hyperplasia of the forestomach was observed. Hence, in a 14-day study, the no observed  adverse effect level (NOAEL) was considered to be 1.25% (w/w) per day (1250 mg/kg bw/day) whereas the low observed adverse effect level (LOAEL) was considered to be 2.5% (w/w) per day (2500 mg/kg bw/day) in F344/N rats dosed with the test chemical.

 

In another repeated dose study, the test chemical at a dosage of 40 mg/kg was investigated to evaluate the potential protective effects against cisplatin (CP)-induced splenotoxicity in rats. In the current study, the test chemical was also given alone for 7 days. These results showed no increase in Hb concentration or lymphocyte count as compared to the saline control or the DMSO control. In addition, a mild decrease in leucocytic count could be seen after test chemical treatment while no changes in the number of neutrophils were seen. A decrease in the MDA activity and an increase in splenic TNF-α level were observed after test chemical treatment as compared to the two different controls. Therefore, no observed adverse effect level (NOAEL) was considered to be 40 mg/kg when the test chemical alone was administered to male Sprague-Dawley rats for 7 days.

 

In a chronic toxicity oral study, the test chemical was evaluated in male and female Osborne-Mendel rats where the test chemical was administered by diet at concentration of 0, 1000, 2500 or 10000 ppm (0, 5, 125 or 500 mg/kg body weight). No effects were noted when the rats were exposed to 2500 ppm (125 mg/kg body weight) while treatment with 10000 ppm (500 mg/kg body weight) resulted in slight hepatic cell swelling and slight hyperkeratosis of squamous portion of the stomach. Therefore, the no observed adverse effect level (NOAEL) was considered to be 125 mg/kg when Osborne-Mendel rats were exposed to the test chemical for 16 weeks.

 

Repeated dose toxicity: Inhalation

 

Cinnamaldehyde has very low vapor pressure (0.0289 mmHg at 25˚C), so the potential for the generation of inhalable vapours is very low. Also the normal conditions of use of this substance will not result in aerosols, particles or droplets of an inhalable size, so exposure to humans via the inhalatory route will be highly unlikely and therefore this end point was considered for waiver.

 

Repeated dose toxicity: Dermal

 

Repeated dose toxicity LOAEL (Lowest observed adverse effect level) of the test chemical to mouse by the dermal route was estimated at a dose concentration of 750 mg/kg bw/day. On the basis of this LOAEL value it is concluded that the test chemical was not toxic to rat by dermal route below the above mentioned dose.

 

Repeated dose toxicity by dermal route was studied on female Balb/c mice. The test chemical was applied to both ears once a day for 3 consecutive days. The no observed adverse effect level (NOAEL) for the test chemical is considered to be 25% (v/v) (5000 mg/kg bw) when tested on mouse.

Based on the data available for the target chemical, the test chemical is not likely to be toxic upon repeated exposure by oral, dermal and inahlation route of exposure.

Justification for classification or non-classification

As evident by 90 days feeding studies, treatment with the test chemical in rats and mice is not associated with significant or severe target organ toxicity or with generalised changes of less severe nature involving multiple organs. Marked body weight decreases were observed at dose levels far above CLP guidance values for STOT RE classification. It should also be mentioned that the observed body weight decrements were accompanied by reduced food intake likely due to poor palatability of the high-dosed food. In two-weeks gavage studies, treatment with the test chemical in rats and mice produced critical effects only at ≥1880 mg/kg bw/day (rats) and at ≥1310 mg/kg bw/day (mice) but not at lower dose levels. Therefore the substance is regarded to be classified as Not Classified for STOT RE by the oral route.