Propyl 3,4,5-trihydroxybenzoate

Carcinogenicity

Description of key information

In two rodent studies conducted similar to OECD TG 451 male and female F344/N rats received propyl gallate daily at doses of 0, 312 and 624 mg/kg bw/d, and male and female B6C3F1 mice received daily doses of 0, 6000 and 12000 mg/kg bw/d in both cases via the diet for 105 -107 weeks. Under the conditions of these studies, there was no evidence of carcinogenic activity. This conclusion was further supported by the EFSA. In the EFSA publication "Scientific Opinion on the re-evaluation of propyl gallate (E310) as a food additive", 2014 several chronic toxicity/carcinogenicity toxicity studies conducted with propyl gallate were presented. It was concluded, that propyl gallate did not induce increased incidence of tumour and is consequently not considered as carcinogenic for mice of either sex. Furthermore, the EFSA Panel concluded that propyl gallate was also not carcinogenic in rats.

Key value for chemical safety assessment

Carcinogenicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 451 (Carcinogenicity Studies)

GLP compliance:

not specified

Specific details on test material used for the study:

- Source and lot/batch No.of test material: Tennessee Eastman Co., Kingsport, TN
- Purity: 100%

Species:

mouse

Strain:

B6C3F1

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: not specified
- Age at study initiation: 4-5 wk old
- Weight at study initiation: Not specified
- Housing: The animals were housed in groups of five in polycarbonate cages (Lab Products, Inc., Garfield, NJ) with Beta Chips (Northeastern Products Corp., Warrensburg, NY) as bedding. Assignment of animals to cages was made according to tables of random numbers.
- Diet (e.g. ad libitum): Ground Wayne Lab Blox feed (Allied Mills, Inc., Chicago, IL) ad libitum
- Water (e.g. ad libitum): tap water as libitum
- Acclimation period: Yes, 13-15 days prior to use in the study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 30-60%
- Air changes (per hr): 15 air changes/hr
- Photoperiod (hrs dark / hrs light): 12 hr light/dark

Route of administration:

oral: feed

Vehicle:

other: ground Wayne Lab Blox feed

Details on exposure:

Experimental diets were prepared by mixing 0, 0.6 or 1.2% Propyl gallate (100% pure; Tennessee Eastman Co., Kingsport, TN) into ground Wayne Lab Blox feed.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

103 weeks

Frequency of treatment:

Diet was available ad libidum.

Post exposure period:

no

Dose / conc.:

0 other: %

Remarks:

Propyl gallate (100% pure) was mixed with ground feed.

Dose / conc.:

0.6 other: %

Remarks:

Propyl gallate (100% pure) was mixed with ground feed.

Dose / conc.:

1.2 other: %

Remarks:

Propyl gallate (100% pure) was mixed with ground feed.

No. of animals per sex per dose:

50

Control animals:

yes, concurrent no treatment

Details on study design:

- Dose selection rationale: The doses of propyl gallate used in this study were selected on the basis of mortality, a decrease in body-weight gain, and the necrosis and ulceration of the mucosa and submucosa of the stomach observed at higher doses in 13-wk studies.

Positive control:

no

Observations and examinations performed and frequency:

DETAILED CLINICAL OBSERVATIONS: Yes, all animals
- Time schedule: observed daily for morbidity, mortality, and for clinical signs of toxicity. Survival data was presented in Table 3.

BODY WEIGHT: Yes, all animals
- Time schedule for examinations: Body weights were recorded weekly for the first 13 weeks, and monthly thereafter. Mean body weight gain for animals surviving to week 103 was presented in Table 3.

FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption for each animal was measured weekly for the first 13 weeks, and monthly thereafter. Mean food consumption (g/mouse/day) was presented in Table 3.

CLINICAL PATHOLOGY: Yes. For each animal that survived until the end of the study, approximately 42 tissues, plus grossly visible lesions, were collected for histopathological examination. Tissues were preserved in 10% neutral buffered formalin, embedded in paraffin, sectioned at 5-6 pm, and stained with haematoxylin and eosin.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, necropsies were performed on all animals that survied until the end of the experiment.

HISTOPATHOLOGY: Yes (see table 5). For each animal that survived until the end of the study, approximately 42 tissues, plus grossly visible lesions, were collected for histopathological examination. Tissues were preserved in 10% neutral buffered formalin, embedded in paraffin, sectioned at 5-6 pm, and stained with haematoxylin and eosin.

Other examinations:

no further data

Statistics:

Differences in survival were analysed by the life table method (Cox, 1972). For the analysis of tumour incidence data, three different procedures were used to make pairwise comparisons and to assess the significance of dose-response trends: (1) life table analysis, appropriate for fatal tumours; (2) an incidental tumour test, appropriate for tumours observed at necropsy in animals dying from an unrelated cause (Peto, Pike, Day et al. 1980); (3) Fisher's exact test and the Cochran-Armitage trend test based on overall proportions of tumour-bearing animals (Gart, Chu & Tarone, 1979). Except where noted, the three analyses gave similar results. All reported P values are one-sided.

Clinical signs:

not specified

Dermal irritation (if dermal study):

not examined

Mortality:

mortality observed, non-treatment-related

Description (incidence):

No significant difference in survival was observed between control and treated mice of either sex.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Mean body weights of treated male and female mice were lower than those of the controls throughout most of the study. Final mean body weights for treated mice relative to controls were 5-8% lower for males and 11% lower for females.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

Average daily food consumption was comparable in control and treated mice of each sex (Table 3).

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

Malignant lymphomas of the haemopoietic system occurred with a positive (P < 0.05) trend in male mice, and the incidence in the 1.2% Propyl gallate dose group was higher (P < 0.05) than in the controls.

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not specified

Description (incidence and severity):

Grossly visible lesions were collected for histopathological examination. No results specifically-related to gross pathological findings were reported.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

not specified

Histopathological findings: neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Noteworthy tumour incidences observed in mice are shown in Table 5. Fibromas of the skin in male mice occurred with a negative (P < 0.05) trend and the incidence in the 1.2% dose group was lower (P < 0.05) than that in the controls. Hepatocellular adenomas in female mice occurred with a positive (P < 0.05) trend, and the incidence in the 1.2% dose group was higher than that in the controls. However, the incidence of hepatocellular adenoma or carcinoma (combined) was similar in control and treated groups. Uterine endometrial stromal polyps or sarcomas in female mice showed a negative (P < 0.05) trend, and the incidence in the 1.2% dose group was lower (P < 0.05) than that in the control.

Other effects:

not specified

Relevance of carcinogenic effects / potential:

Tumours commonly occurring in F344 rats were seen in both control and Propyl gallate-treated animals, but these were not considered to be compound-related. In those instances where a significant increase in tumour incidence in treated animals was noted, the biological significance was discounted when one of the following conditions was met: (a) a significant increase in tumour incidence was noted in only the low dose group or (b) the incidence was not significantly different from historical control rates. Similarly, the elevated incidences of malignant lymphoma in high dose (1.2% Propyl gallate) male mice and hepatocellular adenoma in high-dose female mice were not considered to be related to the administration of this compound.

Dose descriptor:

LOAEL

Effect level:

1.2 other: %

Based on:

not specified

Sex:

male

Basis for effect level:

haematology

Remarks on result:

other: Malignant lymphomas of the haemopoietic system occurred with a positive (P < 0.05) trend in male mice, and the incidence in the 1.2% propyl gallate dose group was higher (8/50; P < 0.05) than in the controls (1/50).

Dose descriptor:

LOAEL

Effect level:

1.2 other: %

Based on:

not specified

Sex:

male

Basis for effect level:

histopathology: neoplastic

Remarks on result:

other: Fibromas of the skin in male mice occurred with a negative (P < 0.05) trend and the incidence in the 1.2% dose group was lower (0/50; P < 0.05) than that in the controls (5/50).

Dose descriptor:

LOAEL

Effect level:

1.2 other: %

Based on:

other:

Sex:

female

Basis for effect level:

histopathology: neoplastic

Remarks on result:

other: Hepatocellular adenomas in female mice occurred with a positive (P < 0.05) trend, and the incidence in the 1.2% dose group was higher than that in the controls.

Dose descriptor:

LOAEL

Effect level:

1.2 other: %

Based on:

not specified

Sex:

female

Basis for effect level:

histopathology: neoplastic

Remarks on result:

other: Uterine endometrial stromal polyps or sarcomas in female mice showed a negative (P < 0.05) trend, and the incidence in the 1.2% dose group was lower (0/49; P < 0.05) than that in the control (3/50).

Conclusions:

In a study equivalent to OECD TG 451 (supervised by NTP) male and female B6C3F1 mice and F344 rats received daily by diet 0, 0.6 and 1.2 % Propyl gallate mixed with ground feed for 103 weeks ad libitum. Propyl gallate caused a dose-related decrease in the growth rate of rats and mice. In male and female rats given 0.6% propyl gallate, tumours at several anatomical sites occurred at a higher (P < 0.05) incidence than in the controls. Undifferentiated leukaemia was also observed with a negative (P < 0.05) trend in male rats given propyl gallate. However, study authors concluded Propyl gallate was not considered to be carcinogenic to F344 rats or B6C3F1 mice of either sex, because the authors refuted significant results if (1) a significant increase in tumour incidence was noted in only the low dose group or (2) the incidence was not significantly different from historical control rates.

Executive summary:

In a study equivalent to OECD TG 451 (supervised by NTP) male and female B6C3F1 mice and F344 rats received daily by diet 0, 0.6 and 1.2 % Propyl gallate mixed with ground feed for 103 weeks ad libitum. Propyl gallate caused a dose-related decrease in the growth rate of rats and mice. In male and female rats given 0.6% propyl gallate, tumours at several anatomical sites occurred at a higher (P < 0.05) incidence than in the controls. Undifferentiated leukaemia was also observed with a negative (P < 0.05) trend in male rats given propyl gallate. However, study authors concluded Propyl gallate was not considered to be carcinogenic to F344 rats or B6C3F1 mice of either sex, because the authors refuted significant results if (1) a significant increase in tumour incidence was noted in only the low dose group or (2) the incidence was not significantly different from historical control rates.

Reference 2

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

comparable to guideline study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 451 (Carcinogenicity Studies)

GLP compliance:

not specified

Specific details on test material used for the study:

- Source and lot/batch No.of test material: Tennessee Eastman Co., Kingsport, TN
- Purity: 100%

Species:

rat

Strain:

Fischer 344

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: not specified
- Age at study initiation: 4-5 wk old
- Weight at study initiation: Not specified
- Housing: The animals were housed in groups of five in polycarbonate cages (Lab Products, Inc., Garfield, NJ) with Beta Chips (Northeastern Products Corp., Warrensburg, NY) as bedding. Assignment of animals to cages was made according to tables of random numbers.
- Diet (e.g. ad libitum): Ground Wayne Lab Blox feed (Allied Mills, Inc., Chicago, IL) ad libitum
- Water (e.g. ad libitum): tap water as libitum
- Acclimation period: Yes, 13-15 days prior to use in the study.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 30-60%
- Air changes (per hr): 15 air changes/hr
- Photoperiod (hrs dark / hrs light): 12 hr light/dark

Route of administration:

oral: feed

Vehicle:

other: ground Wayne Lab Blox feed

Details on exposure:

Experimental diets were prepared by mixing 0, 0.6 or 1.2% propyl gallate (100% pure; Tennessee Eastman Co., Kingsport, TN) into ground Wayne Lab Blox feed.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

103 weeks

Frequency of treatment:

Diet was available ad libidum.

Post exposure period:

no

Dose / conc.:

0 other: %

Remarks:

Propyl gallate (100% pure) was mixed with ground feed.

Dose / conc.:

0.6 other: %

Remarks:

Propyl gallate (100% pure) was mixed with ground feed.

Dose / conc.:

1.2 other: %

Remarks:

Propyl gallate (100% pure) was mixed with ground feed.

No. of animals per sex per dose:

50

Control animals:

yes, concurrent no treatment

Details on study design:

- Dose selection rationale: The doses of propyl gallate used in this study were selected on the basis of mortality, a decrease in body-weight gain, and the necrosis and ulceration of the mucosa and submucosa of the stomach observed at higher doses in 13-wk studies.

Positive control:

no

Observations and examinations performed and frequency:

DETAILED CLINICAL OBSERVATIONS: Yes, all animals
- Time schedule: observed daily for morbidity, mortality, and for clinical signs of toxicity. Survival data was presented in Table 3.

BODY WEIGHT: Yes, all animals
- Time schedule for examinations: Body weights were recorded weekly for the first 13 weeks, and monthly thereafter. Mean body weight gain for animals surviving to week 103 was presented in Table 3.

FOOD CONSUMPTION AND COMPOUND INTAKE:
- Food consumption for each animal was measured weekly for the first 13 weeks, and monthly thereafter. Mean food consumption (g/rat/day) was presented in Table 3.

CLINICAL PATHOLOGY: Yes. For each animal that survived until the end of the study, approximately 42 tissues, plus grossly visible lesions, were collected for histopathological examination. Tissues were preserved in 10% neutral buffered formalin, embedded in paraffin, sectioned at 5-6 pm, and stained with haematoxylin and eosin.

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, necropsies were performed on all animals that survied until the end of the experiment.

HISTOPATHOLOGY: Yes (see table 4). For each animal that survived until the end of the study, approximately 42 tissues, plus grossly visible lesions, were collected for histopathological examination. Tissues were preserved in 10% neutral buffered formalin, embedded in paraffin, sectioned at 5-6 pm, and stained with haematoxylin and eosin.

Other examinations:

no further data

Statistics:

Differences in survival were analysed by the life table method (Cox, 1972). For the analysis of tumour incidence data, three different procedures were used to make pairwise comparisons and to assess the significance of dose-response trends: (1) life table analysis, appropriate for fatal tumours; (2) an incidental tumour test, appropriate for tumours observed at necropsy in animals dying from an unrelated cause (Peto, Pike, Day et al. 1980); (3) Fisher's exact test and the Cochran-Armitage trend test based on overall proportions of tumour-bearing animals (Gart, Chu & Tarone, 1979). Except where noted, the three analyses gave similar results. All reported P values are one-sided.

Clinical signs:

not specified

Dermal irritation (if dermal study):

not examined

Mortality:

mortality observed, non-treatment-related

Description (incidence):

There were no differences in survival between control and treated groups of rats of either sex (Table 3).

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Throughout the study, lower body weights were observed in treated rats. Mean body weights for rats given 0.6 or 1.2% propyl gallate in the diet were 4 and 8% lower than controls for males and 11 and 19% lower for females.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

Average daily food consumption by control and dosed groups was comparable.

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

effects observed, treatment-related

Description (incidence and severity):

Undifferentiated leukaemia occurred with a negative (P < 0.05) trend in male rats given Propyl gallate (16/50, 7/50, 6/50).

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

not specified

Description (incidence and severity):

Grossly visible lesions were collected for histopathological examination. No results specifically-related to gross pathological findings were reported.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Cytoplasmic vacuolization of the liver was observed in 22/50 male rats receiving 1.2% Propyl gallate compared with 4/50 in the controls. Suppurative inflammation of the prostate gland was more prevalent in male rats given 1.2% Propyl gallate (30/50) than in the control (17/50) or the 0.6% dose groups (18/46). Nephrosis in female rats was more prevalent in the 0.6% dose group (28/50) than in the control group (8/50) or in the 1.2% dose group (4/50).

Histopathological findings: neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Noteworthy tumour incidences observed in rats are shown in Table 4. In male rats given 0.6% Propyl gallate, tumours at several anatomical sites occurred at a higher (P < 0.05) incidence than in the controls. These included phaeochromocytomas of the adrenal gland, islet-cell adenomas of the pancreas, and adenomas, adenocarcinomas or carcinomas of the preputial and thyroid glands. For these tumours, the incidences in control rats and in rats given 1.2% propyl gallate were not significantly different (Table 4). In female rats, uterine endometrial stromal polyps occurred with a positive (P < 0.05) trend. However, in neither of the treated groups was the incidence significantly different from the controls. Mammary-gland adenomas were observed in three out of 50 female rats given 1.2% Propyl gallate. However, none was seen in the controls or in the females given 0.6%. Fibroadenomas of the mammary gland of females occurred with a negative (P < 0.05) trend, and the incidence in females at the 0.6% dose level was lower (P < 0.05) than in the controls.

Other effects:

not specified

Relevance of carcinogenic effects / potential:

Tumours commonly occurring in F344 rats were seen in both control and Propyl gallate-treated animals, but these were not considered to be compound-related. In those instances where a significant increase in tumour incidence in treated animals was noted, the biological significance was discounted when one of the following conditions was met: (a) a significant increase in tumour incidence was noted in only the low dose group or (b) the incidence was not significantly different from historical control rates. Accordingly, the increased incidences of thyroid follicular cell adenoma or carcinoma (combined) in treated male rats and the increased incidences of preputial gland tumours, pancreatic islet-cell tumours, and phaeochromocytoma of the adrenal gland in low-dose male rats were not considered to be related to Propyl gallate administration.

Dose descriptor:

LOAEL

Effect level:

0.6 other: %

Based on:

not specified

Sex:

male/female

Basis for effect level:

body weight and weight gain

Remarks on result:

other: Mean body weights for rats given 0.6 or 1.2% propyl gallate in the diet were 4 and 8% lower than controls for males and 11 and 19% lower for females.

Dose descriptor:

dose level:

Effect level:

0.6 other: %

Based on:

not specified

Sex:

male

Basis for effect level:

histopathology: neoplastic

Remarks on result:

other: In male rats given 0.6% Propyl gallate, phaeochromocytomas of the adrenal gland occurred at a higher (13/48; P < 0.05) incidence than in the controls.

Dose descriptor:

dose level:

Effect level:

0.6 other: %

Based on:

not specified

Sex:

male

Basis for effect level:

histopathology: neoplastic

Remarks on result:

other: In male rats given 0.6% Propyl gallate, islet-cell adenomas of the pancreas occurred at a higher (8/50; P < 0.05) incidence than in the controls.

Dose descriptor:

dose level:

Effect level:

0.6 other: %

Based on:

not specified

Sex:

male

Basis for effect level:

histopathology: neoplastic

Remarks on result:

other: In male rats given 0.6% Propyl gallate, adenomas of the preputial gland occurred at a higher (5/50; P < 0.05) incidence than in the controls.

Dose descriptor:

LOAEL

Effect level:

0.6 other: %

Based on:

not specified

Sex:

male

Basis for effect level:

haematology

Remarks on result:

other: Undifferentiated leukaemia occurred with a negative (P < 0.05) trend in male rats given Propyl gallate (16/50, 7/50, 6/50).

Dose descriptor:

dose level:

Effect level:

0.6 other: %

Based on:

not specified

Sex:

female

Basis for effect level:

histopathology: neoplastic

Remarks on result:

other: Fibroadenomas of the mammary gland of females occurred with a negative (P < 0.05) trend, and the incidence in females at the 0.6% dose level was lower (P < 0.05) than in the controls.

Conclusions:

In a study equivalent to OECD TG 451 (supervised by NTP) male and female B6C3F1 mice and F344 rats received daily by diet 0, 0.6 and 1.2 % Propyl gallate mixed with ground feed for 103 weeks ad libitum. Propyl gallate caused a dose-related decrease in the growth rate of rats and mice. In male and female rats given 0.6% propyl gallate, tumours at several anatomical sites occurred at a higher (p< 0.05) incidence than in the controls. Undifferentiated leukaemia was also observed with a negative (p < 0.05) trend in male rats given propyl gallate. However, study authors concluded Propyl gallate was not considered to be carcinogenic to F344 rats or B6C3F1 mice of either sex, because the authors refuted significant results if (1) a significant increase in tumour incidence was noted in only the low dose group or (2) the incidence was not significantly different from historical control rates.

Executive summary:

In a study equivalent to OECD TG 451 (supervised by NTP) male and female B6C3F1 mice and F344 rats received daily by diet 0, 0.6 and 1.2 % Propyl gallate mixed with ground feed for 103 weeks ad libitum. Propyl gallate caused a dose-related decrease in the growth rate of rats and mice. In male and female rats given 0.6% propyl gallate, tumours at several anatomical sites occurred at a higher (p< 0.05) incidence than in the controls. Undifferentiated leukaemia was also observed with a negative (p < 0.05) trend in male rats given propyl gallate. However, study authors concluded Propyl gallate was not considered to be carcinogenic to F344 rats or B6C3F1 mice of either sex, because the authors refuted significant results if (1) a significant increase in tumour incidence was noted in only the low dose group or (2) the incidence was not significantly different from historical control rates.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Study duration:

chronic

Species:

rat

Carcinogenicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Carcinogenicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Based on the available data and according to criteria of Regulation (EC) No. 1272/2008 classification for carcinogenicity is not warranted.

Additional information

In two rodent studies conducted similar to OECD TG 451 male and female F344/N rats received propyl gallate daily at doses of 0, 312 and 624 mg/kg bw/d, and male and female B6C3F1 mice received daily doses of 0, 6000 and 12000 mg/kg bw/d in both cases via the diet for 105 -107 weeks. Under the conditions of these studies, there was no evidence of carcinogenic activity. This conclusion was further supported by the EFSA. In the EFSA publication "Scientific Opinion on the re-evaluation of propyl gallate (E310) as a food additive", 2014 several chronic toxicity/carcinogenicity toxicity studies conducted with propyl gallate were presented. It was concluded, that propyl gallate did not induce increased incidence of tumour and is consequently not considered as carcinogenic for mice of either sex. Furthermore, the EFSA Panel concluded that propyl gallate was also not carcinogenic in rats.