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EC number: 208-293-9 | CAS number: 520-45-6
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
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- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
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- Nanomaterial dustiness
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- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Endpoint summary
Administrative data
Description of key information
Study 001: rat gavage doses 10 to 300 mg/kg bw/day, 24 doses in 34 days; treatment related mortality and adverse toxicity at 300 mg/kg bw/day. No adverse effects at 0, 10, 30, 100 mg/kg bw/day. NOAEL 100 mg/kg bw/day.
Study 002: rat dietary 0.02, 0.05, and 0.10 % (by weight, DHA – equivalent to 200, 500 or 1000 ppm or 16, 39 or 78 mg/kg bw/day). Two-year study, 25 animals/group. No adverse effects. NOEL 1000 ppm (78 mg/kg bw/day).
Study 003: monkey (Macaca mulatta) gavage doses 0, 50, 100, 200 or 300 mg/kg bw/day (single animal/group)– DHA equivalent, DHA or DHA-Na dosed. One-year study, for doses up to 100 mg/kg bw/day no adverse toxicity. Adverse toxicity at 200 or 300 mg/kg bw/day. NOAEL 100 mg/kg bw/day.
Study 004: rat dietary 2500 ppm for 350 days -12 male rats treated group. Part of the study was designed investigate the adverse effects of 4-(dimethylamino)azobenzene (DAB) and any effects DHA may have on its own or in combination with DAB. DHA had no adverse toxic effects, NOAEL 2500 ppm (equivalent to 250 mg/kg/bw/day). The data suggested that DHA delayed the induction of hepatomas and cholangiocarcinoma’s in rats fed DAB.
Study 005: rat dietary 20 mg/day/head (dose in mg/kg not stated), 20 male rats treated 15 weeks with DHA. Transient body weight and food consumption reduced, liver weight increased with concomitant enzyme induction. No NOAEL.
Key value for chemical safety assessment
Repeated dose toxicity: via oral route - systemic effects
Link to relevant study records
- Endpoint:
- short-term repeated dose toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- Circa 1950
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- test procedure in accordance with generally accepted scientific standards and described in sufficient detail
- Qualifier:
- no guideline available
- Principles of method if other than guideline:
- Essentially an oral gavage four-week sub-acute toxicity study, conducted in the rat (a well-established experimental model), in which key toxicity endpoints were evaluated.
- GLP compliance:
- no
- Limit test:
- no
- Species:
- rat
- Strain:
- not specified
- Sex:
- male
- Details on test animals or test system and environmental conditions:
- Not specified
- Route of administration:
- oral: gavage
- Vehicle:
- olive oil
- Analytical verification of doses or concentrations:
- not specified
- Duration of treatment / exposure:
- 24 doses in 34 days
- Frequency of treatment:
- Daily - presumed not at weekends
- Dose / conc.:
- 0 mg/kg bw/day (nominal)
- Remarks:
- Vehicle control
- Dose / conc.:
- 10 mg/kg bw/day (nominal)
- Dose / conc.:
- 30 mg/kg bw/day (nominal)
- Dose / conc.:
- 100 mg/kg bw/day (nominal)
- Dose / conc.:
- 300 mg/kg bw/day (nominal)
- No. of animals per sex per dose:
- 5 or 6
- Control animals:
- yes, concurrent vehicle
- Details on study design:
- Male rats 10 weeks old at start of study
- Positive control:
- No
- Observations and examinations performed and frequency:
- General condition, body weight
- Sacrifice and pathology:
- Pathology (lung, heart, liver, kidney, spleen, adrenal, pancreas, testis, and stomach), histopathology, blood urea-N
- Clinical signs:
- effects observed, treatment-related
- Description (incidence and severity):
- At 300 mg/kg bw/day - animals were emaciated, thin and unkempt
- Mortality:
- mortality observed, treatment-related
- Description (incidence):
- At 300 mg/kg bw/day - two deaths, one at 7 days the other at 11 days (7 doses)
Remaining rats killed after 11 days
No adverse effects at 0, 10, 30, 100 mg/kg bw/day - Body weight and weight changes:
- effects observed, treatment-related
- Description (incidence and severity):
- At 300 mg/kg bw/day - 20 to 30% of their body weight loss
No adverse effects at 0, 10, 30, 100 mg/kg bw/day - 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:
- no effects observed
- Description (incidence and severity):
- Blood urea-N was determined; the data were inconclusive
- Urinalysis findings:
- not specified
- Behaviour (functional findings):
- not specified
- Immunological findings:
- not specified
- Organ weight findings including organ / body weight ratios:
- no effects observed
- Gross pathological findings:
- effects observed, treatment-related
- Description (incidence and severity):
- At 300 mg/kg bw/day - contracted stomach with blood tinged contents, a congested mucosa, and a few haemorrhagic areas.
No adverse effects at t 0, 10, 30, 100 mg/kg bw/day - Neuropathological findings:
- not specified
- Histopathological findings: non-neoplastic:
- no effects observed
- Description (incidence and severity):
- No adverse effects at 0, 10, 30, 100 mg/kg bw/day
- Histopathological findings: neoplastic:
- not examined
- Other effects:
- not specified
- Key result
- Dose descriptor:
- LOEL
- Effect level:
- ca. 300 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Sex:
- male
- Basis for effect level:
- body weight and weight gain
- clinical signs
- mortality
- Remarks on result:
- other:
- Key result
- Dose descriptor:
- NOAEL
- Effect level:
- >= 100 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Sex:
- male
- Basis for effect level:
- other: No adverse toxicity at 100 mg/kg bw/day.
- Key result
- Critical effects observed:
- yes
- Lowest effective dose / conc.:
- 300 mg/kg bw/day (nominal)
- System:
- gastrointestinal tract
- Organ:
- stomach
- Treatment related:
- yes
- Dose response relationship:
- not specified
- Relevant for humans:
- not specified
- Conclusions:
- General condition and body weight at 0, 10, 30, 100 mg/kg bw/day was unaffected. Additionally, no adverse effects were noted for blood urea-N or after histopathological examination of selected tissues (lung, heart, liver, kidney, spleen, adrenal, pancreas, testis, and stomach). At 300 mg/kg bw/day loss, two deaths occurred (7 & 11 days). The remaining animals at 300 mg/kg bw/day were killed after 11 days (7 doses). These animals lost 20 to 30% of their body weight and were thin and unkempt. Examination of each of these animals revealed marked emaciation and contracted stomach with blood tinged contents, a congested mucosa, and a few haemorrhagic areas. The NOAEL was onsidered to be 100 mg/kg bw/day.
- Executive summary:
In a repeat dose toxicity study (24 doses in 34 days) rats were dosed by oral gavage: 2 groups of 5 or 6 (10 weeks old at start), the dosages were: 0, 10, 30, 100 or 300 mg/kg bw/day (vehicle: olive oil).
There were no adverse effects at 10, 30, 100 mg/kg bw/day. At 300 mg/kg bw/day loss, two deaths occurred (7 & 11 days), there was 20 to 30% body weight loss, the animals appeared thin and unkempt and had a contracted stomach with blood tinged contents, a congested mucosa, and a few haemorrhagic areas. A NOAEL of 100 mg/kg bw/day was determined.
- Endpoint:
- chronic toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- Circa 1950
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- test procedure in accordance with generally accepted scientific standards and described in sufficient detail
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- Primarily a chronic dietary, two-year, study in rats in which key indicators of toxicity and pathology were monitored. Additionally, some TK parameters were assessed.
- GLP compliance:
- no
- Limit test:
- no
- Species:
- rat
- Strain:
- not specified
- Details on species / strain selection:
- 2-3 months old at commencement of study
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- Details not specified
Diet was a modified Sherman diet - Route of administration:
- oral: feed
- Details on route of administration:
- Note: Diets containing 0.02, 0.05, and 0.10 % (by weight) DHA – equivalent to 200, 500 or 1000 ppm (calculation approx. 16, 39 or 78 mg/kg bw /day).
- Vehicle:
- unchanged (no vehicle)
- Details on oral exposure:
- Two year feeding study
- Analytical verification of doses or concentrations:
- not specified
- Duration of treatment / exposure:
- Two years
- Frequency of treatment:
- Daily in diet
- Dose / conc.:
- 0 ppm
- Dose / conc.:
- 200 ppm
- Remarks:
- 0.02% or 16 mg/kg bw/day
- Dose / conc.:
- 500 ppm
- Remarks:
- 0.05% or 39 mg/kg bw/day
- Dose / conc.:
- 1 000 ppm
- Remarks:
- 0.10% or 78 mg/kg bw/day
- No. of animals per sex per dose:
- 25
- Control animals:
- yes, concurrent no treatment
- Details on study design:
- Rats 2-3 months old; 25 each sex/group; 5 same sex/cage, food & water ad lib.
A group of ten female rats, receiving the diet containing 0.05% DHA, and a similar group of controls, were selected for periodic hematological studies during the course of the experiment - Positive control:
- No
- Observations and examinations performed and frequency:
- Clinical condition, body weight and food consumption (twice/week) , haematology (erythrocyte count, haemoglobin concentration, total leucocyte count, and differential count) - frequency not specified
- Sacrifice and pathology:
- After 237 days on the experimental diets, two female rats from each of the groups were sacrificed in order to obtain plasma for DHA analyses
After two years on the diets containing DHA all of the surviving rats were starved overnight, weighed, killed by decapitation, aud examined. The.heart, liver, kidneys, spleen, and testes from,each rat were weighed. - Other examinations:
- Oxalated blood was taken for urea-N determinations and a portion of the liver from each animal was frozen with dry ice for subsequent analysis of the total lipid content. Total lipids were determined gravimetrically.
- Statistics:
- The t-test was used in comparing the mean values obtained on the experimental groups with those of the controls; probability values (P) of 0.05 or less indicated a signiûcant difference.
- Clinical signs:
- no effects observed
- Mortality:
- mortality observed, non-treatment-related
- Description (incidence):
- Considered to be age-related and to infection
- Body weight and weight changes:
- no effects observed
- Food consumption and compound intake (if feeding study):
- no effects observed
- Food efficiency:
- not specified
- Water consumption and compound intake (if drinking water study):
- not specified
- Ophthalmological findings:
- not specified
- Haematological findings:
- no effects observed
- Clinical biochemistry findings:
- effects observed, treatment-related
- Description (incidence and severity):
- At termination, the total liver lipid values were significantly higher in the 1000 ppm dose group.
- Urinalysis findings:
- not specified
- Behaviour (functional findings):
- no effects observed
- Immunological findings:
- not specified
- Organ weight findings including organ / body weight ratios:
- no effects observed
- Gross pathological findings:
- effects observed, non-treatment-related
- Description (incidence and severity):
- Mild fatty changes in the liver were observed in most of the animals in each of the groups, control as well as experimental. These changes were usually very mild in degree (as substantiated by the liver weights and liver lipid values) and were observed in Oil Red O stained sections as small, brilliantly stained globules diffuse in distribution, although usually most numerous in the periportal areas.
- Neuropathological findings:
- not specified
- Histopathological findings: non-neoplastic:
- effects observed, non-treatment-related
- Description (incidence and severity):
- Mild fatty changes in the liver were observed in most of the animals in each of the groups, control as well as experimental
- Histopathological findings: neoplastic:
- no effects observed
- Other effects:
- no effects observed
- Key result
- Dose descriptor:
- NOAEL
- Effect level:
- ca. 1 000 ppm
- Based on:
- test mat.
- Remarks:
- 78 mg/kg bw/day
- Sex:
- male/female
- Basis for effect level:
- histopathology: non-neoplastic
- other: Liver lipid analysis
- Critical effects observed:
- not specified
- Conclusions:
- General condition and body weight during the in-life phase at all doses were essentially similar. At termination, the body weights of the males were higher than the controls. Haematological parameters were unaffected. No adverse treatment related pathological changes at any dosage were reported. Changes seen after terminal necropsy were considered to be related to the age of the rats. At termination, the total liver lipid values were significantly higher in the top dose group.
No histopathological changes were seen at any dosage, however lipid staining of the livers revealed staining particularly in the periportal areas. There were also some incidences of hyaline casts in the renal tubules but there was no apparent relationship to treatment. The NOAEL was consider to be 1000 ppm (78 mg/kg bw/day). - Executive summary:
Male and female rats treated via the diet for 2 years with DHA were not adversely affected by treatment at any dosage. Lipid staining of the livers revealed some staining aprticularly in the periportal areas, additionally the lipid content of the liver was increased at 1000 ppm, an adverse relationship to treatment was not concluded. A NOAEL of 1000 ppm (78 mg/kg bw/day) was considered appropriate.
- Endpoint:
- sub-chronic toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Study period:
- Circa 1950
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- test procedure in accordance with generally accepted scientific standards and described in sufficient detail
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- A sub-chronic, one-year, study in primates, dosed by oral gavage, in which key indicators of toxicity and pathology were monitored. Additionally, some toxicokinetic parameters were assessed.
- GLP compliance:
- no
- Limit test:
- no
- Species:
- monkey
- Strain:
- other: Macaca mulatta
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- Imported rhesus monkeys (Macaca mulatta), that had been acclimatised for several months in the laboratory were fully adapted to the laboratory environment, diet, and handling, were used in this work.
The animals were caged separately aud maintained on "Complete Laboratory Chow" (Purina) supplemented with canned tomatoes, fresh fruits and vegetables, and peanuts.
At the start of the experiment tho monkeys were apparently in excellent condition and had all gained considerable weight since their arrival in the laboratory. - Route of administration:
- oral: gavage
- Details on route of administration:
- Repeated oral doses of dehydroacetic acid in olive oil solution (5% cent) and of its sodium salt in water solution (10% cent) were administered by stomach tube to these monkeys at dosage levels of 0, 50, 100, 200 or 300 mg/kg bw/day – DHA equivalent, DHA or DHA-Na dosed.
All doses of tho sodium salt were calculated on the basis of its dehydroacetic acid equivalent. - Vehicle:
- olive oil
- Remarks:
- Or water
- Analytical verification of doses or concentrations:
- not specified
- Duration of treatment / exposure:
- One year
- Frequency of treatment:
- Daily - not precisely specified in publication.
- Dose / conc.:
- 0 mg/kg bw/day (nominal)
- Remarks:
- Control
- Dose / conc.:
- 50 mg/kg bw/day (nominal)
- Remarks:
- DHA or DHA-Na
- Dose / conc.:
- 100 mg/kg bw/day (nominal)
- Remarks:
- DHA or DHA-Na
- Dose / conc.:
- 200 mg/kg bw/day (nominal)
- Remarks:
- DHA or DHA-Na
- Dose / conc.:
- 300 mg/kg bw/day (nominal)
- Remarks:
- DHA or DHA-Na
- No. of animals per sex per dose:
- One/group; with the exception of one animal (no. 90) all animals were female
- Control animals:
- yes, concurrent vehicle
- Details on study design:
- Monkeys at 200 mg/kg bw/day dosed only 3-4 days a week due to adverse clinical condition.
- Positive control:
- No
- Observations and examinations performed and frequency:
- Twice weekly body weights, daily observations.
Blood taken periodically for haematology, plasma N content and DHA analysis. Urine was also examined for DHA analysis. - Sacrifice and pathology:
- Sacrificed at one year, heart, liver, kidneys and spleen sampled; blood taken for urea-N analysis and lung, heart, kidney, spleen, adrenal, pancreas testis, ovary, bone marrow stomach, small intestine, voluntary muscle, bladder, lymph node, thyroid and brain sampled for histopathological examination.
Liver and kidney stained with Oil Red O for lipid assessment. - Clinical signs:
- effects observed, treatment-related
- Description (incidence and severity):
- At 300 mg/kg bw/day inappetence, ataxia, vomiting and clonic and tonic convulsions.
Monkeys at this dosage were killed before scheduled termination.
At 200 mg/kg bw/day ataxia, conjvulsions, retching, salivation and vomiting - discontinuation of dosing for up to 3 days lead to a recovery; - Mortality:
- mortality observed, treatment-related
- Description (incidence):
- One monkey (no. 95) on day 26 (after the 20th dose)
- Body weight and weight changes:
- effects observed, treatment-related
- Description (incidence and severity):
- At 200 or 300 mg/kg bw/day body weight loss.
- Food consumption and compound intake (if feeding study):
- effects observed, treatment-related
- Description (incidence and severity):
- At 200 or 300 mg/kg bw/day inappetance recorded.
- Food efficiency:
- not specified
- Water consumption and compound intake (if drinking water study):
- not specified
- Ophthalmological findings:
- not specified
- Haematological findings:
- no effects observed
- Description (incidence and severity):
- No effects recorded at 200 mg/kg bw/day or below.
- Clinical biochemistry findings:
- effects observed, non-treatment-related
- Description (incidence and severity):
- No effects recorded at 200 mg/kg bw/day or below.
- Urinalysis findings:
- not specified
- Behaviour (functional findings):
- not specified
- Immunological findings:
- not specified
- Organ weight findings including organ / body weight ratios:
- no effects observed
- Gross pathological findings:
- effects observed, non-treatment-related
- Description (incidence and severity):
- No effects recorded at 200 mg/kg bw/day or below.
- Neuropathological findings:
- effects observed, treatment-related
- Description (incidence and severity):
- At 200 or 300 mg/kg bw/day ataxia, convulsions.
- Histopathological findings: non-neoplastic:
- effects observed, non-treatment-related
- Description (incidence and severity):
- No effects recorded at 200 mg/kg bw/day or below.
At 300 mg/kg bw/day one animal show moderate degenerative changes to the tubular epithelium of the kidney. Considerable inflammation in the small intestine was noted for the animal which died. - Histopathological findings: neoplastic:
- not specified
- Other effects:
- effects observed, non-treatment-related
- Description (incidence and severity):
- In one monkey treated at 50 mg/kg bw/day the total lipid content of the liver was increased.
- Dose descriptor:
- LOAEL
- Effect level:
- >= 200 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Sex:
- female
- Basis for effect level:
- clinical signs
- Key result
- Dose descriptor:
- NOAEL
- Effect level:
- >= 100 mg/kg bw/day (nominal)
- Based on:
- test mat.
- Sex:
- female
- Critical effects observed:
- not specified
- Conclusions:
- At 300 mg/kg bw/day the monkeys were killed (before scheduled termination due to adverse toxicity: inappetence, body weight loss, ataxia, vomiting and clonic and tonic convulsions. One animal show moderate degenerative changes to the tubular epithelium of the kidney. Considerable inflammation in the small intestine was noted for the animal which died.
At 200 mg/kg bw/day inappetence and body weight loss were seen; discontinuation of dosing for up to 3 days lead to a recovery; however, if this wasn’t the case the animals failed showing signs of ataxia, retching, salivation and vomiting. Force feeding the animals helped to alleviate the symptoms. Because of this animals in this group were dosed 3 or 4 times a week only.
At 50 or 100 mg/kg bw/day no adverse effects were observed. There were no changes in either the blood chemistry of haematological investigations. No adverse histopathological abnormalities were seen in this study with the exception of a monkey treated at 50 mg/kg bw/day where the total lipid content of the liver was increased. A NOAEL of 100 mg/kg bw/day was determined. - Executive summary:
Monkeys (Macaca mulatta) -1/group - were treated with DHA via oral gavage at 0, 50, 100, 200 or 300 mg/kg bw/day.
At 300 mg/kg bw/day the monkeys were killed (before scheduled termination) due to adverse toxicity.
At 200 mg/kg bw/day inappetence and body weight loss were seen.
At 50 or 100 mg/kg bw/day no adverse effects were observed.
- Endpoint:
- chronic toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Study period:
- Circa 1968
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- test procedure in accordance with generally accepted scientific standards and described in sufficient detail
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- A chronic study in the rat, dietary exposure, which was designed to investigate the ameliorative properties of DHA on tumours induced by 4-(dimethylamino)azobenzene (DAB). Key parameters of toxicity were evaluated.
- GLP compliance:
- no
- Limit test:
- no
- Species:
- rat
- Strain:
- Wistar
- Sex:
- male
- Details on test animals or test system and environmental conditions:
- Male rats weighing 105 to 150 g were placed in experimental groups fed on a powered diet (CE-2, CLEA Japan Inc.) which incorporated the test material.
- Route of administration:
- oral: feed
- Vehicle:
- unchanged (no vehicle)
- Details on oral exposure:
- 350 days exposure for DHA treated rats.
- Analytical verification of doses or concentrations:
- not specified
- Duration of treatment / exposure:
- 350 days
- Frequency of treatment:
- Daily
- Dose / conc.:
- 0 ppm
- Remarks:
- Control
- Dose / conc.:
- 2 500 ppm
- Remarks:
- 0.25% DHA or 250 mg/kg bw/day
- No. of animals per sex per dose:
- 12 males at 2500 ppm.
- Control animals:
- yes, concurrent no treatment
- Details on study design:
- The study was designed to investigte the adverse effects of 4-(dimethylamino)azobenzene (DAB), and any effects DHA may have on its own or in combination with DAB.
The treament groups are given below. Treatment group 1-D is most relevant and only reviewed here.
Group 1-A: 22 rats were fed 0.06% DAB diet for 126 days and then basal diet for 162 days.
Group 1-B: 21 rats, fed 0.06% DAB diet for 126 days and then 0.25% dehydroacetic acid diet for 162 days.
Group 1-C: 16 rats, fed 0.06% DAB plus 0.25% dehydroacetic acid diet for 173 days and then basal diet for 77 days.
Group 1-D: 12 rats, fed 0.25% dehydroacetic acid diet for 350 days. - Observations and examinations performed and frequency:
- Not precisely specified.
- Sacrifice and pathology:
- After 350 days on study for DHA treated rats
- Clinical signs:
- no effects observed
- Description (incidence and severity):
- No adverse findings were observed in DHA treated rats
- Mortality:
- no mortality observed
- Description (incidence):
- No adverse findings were observed in DHA treated rats
- Body weight and weight changes:
- no effects observed
- Description (incidence and severity):
- No adverse findings were observed in DHA treated rats
- 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:
- no effects observed
- Description (incidence and severity):
- No adverse findings were observed in DHA treated rats
- 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 adverse findings were observed in DHA treated rats
- Gross pathological findings:
- no effects observed
- Description (incidence and severity):
- No adverse findings were observed in DHA treated rats.
- Neuropathological findings:
- not specified
- Histopathological findings: non-neoplastic:
- no effects observed
- Description (incidence and severity):
- No adverse histopathological findings were observed in DHA treated rats.
- Histopathological findings: neoplastic:
- no effects observed
- Other effects:
- effects observed, treatment-related
- Description (incidence and severity):
- Administration of dehydroacetic acid increased the liver activity of metabolizing azo dyes in both demethylation and reductive cleavage.
- Dose descriptor:
- NOAEL
- Effect level:
- >= 2 500 ppm
- Based on:
- test mat.
- Remarks:
- 250 mg/kg bw/day
- Sex:
- male
- Remarks on result:
- not determinable due to absence of adverse toxic effects
- Critical effects observed:
- not specified
- Conclusions:
- DHA fed to Wistar rats for up to 350 days at 2500 ppm had no adverse toxicity in this study.
- Executive summary:
DHA fed to Wistar rats for up to 350 days at 2500 ppm (250 mg/kg bw/day) had no adverse toxicity in this study. The data suggested that DHA delayed the induction of hepatomas and cholangiocarcinomas in rats fed DAB.
- Endpoint:
- sub-chronic toxicity: oral
- Type of information:
- experimental study
- Adequacy of study:
- other information
- Study period:
- Circa 1975
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- test procedure in accordance with generally accepted scientific standards and described in sufficient detail
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- Essentially a sub-chronic oral toxicity study, dietary, using a single treatment level. Key parameters of toxicity were assessed with some toxicokinetic analyses also.
- GLP compliance:
- no
- Limit test:
- no
- Species:
- rat
- Strain:
- Sprague-Dawley
- Sex:
- male
- Details on test animals or test system and environmental conditions:
- Feed (described as basic feed) and water were provided in fixed quantities at regular intervals, and the mass of any remaining food was recorded. Additionally, the body weight of each animal was measured twice a week and the environment was maintained at a temperature of 22°C and humidity of approximately 65%.
- Route of administration:
- oral: feed
- Details on route of administration:
- To accommodate animal growth, animals were initially given 15 g of feed (dry weight), which was later increased to 20 g. Dehydrated acetic acid (and tobacco extract) were prepared as solutions at a pre-determined concentration and mixed into the hot water used to form animals' feed into spherical dumplings.
- Vehicle:
- water
- Remarks:
- Mixed into diet.
- Analytical verification of doses or concentrations:
- not specified
- Duration of treatment / exposure:
- 15 weeks.
- Frequency of treatment:
- Daily in diet
- Dose / conc.:
- 0 other:
- Remarks:
- Control
- Dose / conc.:
- 20 other: mg/day/head
- Remarks:
- DHA
- No. of animals per sex per dose:
- 20/group
- Control animals:
- yes, concurrent vehicle
- Positive control:
- No
- Observations and examinations performed and frequency:
- Body weights twice a week; feed intake, observations - assumed at least weekly.
- Sacrifice and pathology:
- At the end of the study, animals were euthanised and autopsies were performed. Organ weights were measured and the liver was immediately frozen, after which enzyme activity was examined. Furthermore, urinary DHA was assayed in the DHA administration group and a phenol sulfophthalein test (PSP-test) was performed in the final phase of the study to evaluate whether changes in renal tubule function occurred after long-term administration, as DHA imay be a renal tubule inhibitor.
- Statistics:
- Yes, but methods not specified.
- Clinical signs:
- no effects observed
- Mortality:
- no mortality observed
- Body weight and weight changes:
- effects observed, treatment-related
- Description (incidence and severity):
- Body weight was reduced in the DHA treated group during the first half of the trial, while in the latter half of the trial body weight growth was actually higher that the control group, though only by a very slight amount.
- Food consumption and compound intake (if feeding study):
- effects observed, treatment-related
- Description (incidence and severity):
- Results showed that overall feed uptake was lower in the DHA group than the control group. The calculated weight gain per unit of feed consumed and this ratio was significantly lower in the DHA group for the first half of the trial (at a significance level of 0.5%), before increasing to greater values than in the control group in the latter half of the trial. The above data suggest that reduced feed uptake was not the only factor responsible for the reduced body weight increase observed in animals administered DHA.
- Food efficiency:
- no effects observed
- Water consumption and compound intake (if drinking water study):
- not specified
- Ophthalmological findings:
- not specified
- Haematological findings:
- not specified
- Clinical biochemistry findings:
- effects observed, treatment-related
- Description (incidence and severity):
- A liver enzyme assay showed that alcohol dehydrogenase activity was reduced in the DHA group.
- Urinalysis findings:
- effects observed, treatment-related
- Description (incidence and severity):
- The amounts of DHA excreted in urine were 2.71 mg, 3.07 mg, 3.02 mg and 2.95 mg in weeks 3, 6, 9 and 12 respectively, corresponding to roughly 15% of the amount administered. Furthermore, a PSP test conducted for the DHA group on the 15th and final week of testing showed that the excretion rate was 27.5% in the administration group versus 51.1% in the control group, indicating that long-term, continuous administration of DHA may result in decreased renal tubular function.
- Behaviour (functional findings):
- no effects observed
- Immunological findings:
- not specified
- Organ weight findings including organ / body weight ratios:
- effects observed, treatment-related
- Description (incidence and severity):
- The relative organ weight (to body weight) of the liver was increased and the kidney decreased.
- Gross pathological findings:
- no effects observed
- Neuropathological findings:
- not specified
- Histopathological findings: non-neoplastic:
- effects observed, treatment-related
- Description (incidence and severity):
- A significant decrease in renal tubule function as well as renal atrophy was observed in the DHA group.
- Histopathological findings: neoplastic:
- not specified
- Dose descriptor:
- other: Single dose level
- Effect level:
- ca. 20 mg/kg diet
- Based on:
- test mat.
- Sex:
- male
- Basis for effect level:
- body weight and weight gain
- clinical biochemistry
- food consumption and compound intake
- histopathology: non-neoplastic
- organ weights and organ / body weight ratios
- Critical effects observed:
- yes
- Lowest effective dose / conc.:
- 20 other: mg/day/head
- System:
- hepatobiliary
- Organ:
- kidney
- liver
- Treatment related:
- yes
- Dose response relationship:
- no
- Relevant for humans:
- not specified
- Conclusions:
- Administration of DHA resulted in transient impaired body weight and food intake performance, decreased hepatic enzyme activity, and compensatory hypertrophy of the liver. Furthermore, a significant decrease in renal tubule function as well as renal atrophy was observed in the DHA group.
- Executive summary:
DHA administered in the diet, 20 mg/day/head, to male rats for 15 weeks resulted in transient impaired body weight and food intake performance, decreased hepatic enzyme activity, and compensatory hypertrophy of the liver. Furthermore, a significant decrease in renal tubule function as well as renal atrophy was observed in the DHA group.
Referenceopen allclose all
Data from the second group of rats treated at 300 mg/kg bw/day were similar to the first group at the same dosage.
See attached results summary from paper
See attached summary of results.
The results suggests that dehydroacetic acid delayed the induction of hepatomas and cholangiocarcinomas in rats fed DAB if dehydroacetic acid was administered simultaneously.
Endpoint conclusion
- Endpoint conclusion:
- adverse effect observed
- Dose descriptor:
- NOAEL
- 78 mg/kg bw/day
- Study duration:
- chronic
- Species:
- rat
- System:
- other: GI tract, liver
- Organ:
- liver
- stomach
Repeated dose toxicity: inhalation - systemic effects
Endpoint conclusion
- Endpoint conclusion:
- no study available
Repeated dose toxicity: inhalation - local effects
Endpoint conclusion
- Endpoint conclusion:
- no study available
Repeated dose toxicity: dermal - systemic effects
Endpoint conclusion
- Endpoint conclusion:
- no study available
Repeated dose toxicity: dermal - local effects
Endpoint conclusion
- Endpoint conclusion:
- no study available
Mode of Action Analysis / Human Relevance Framework
These data suggest the liver may be a target, e.g. liver enlargement and enzyme induction. This may be an adaptive response, no overt adverse pathology of the liver stated.
Additional information
Justification for classification or non-classification
No significant adverse toxicity/pathology on the organs and tissues examined was noted . Changes in the liver (weight, pathology, metabolism) were considered to be in relation to xenobiotic induced changes in metabolism and therefore an adaptive response.
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