trans-menthone

Endpoint summary

Description of key information

Repeated dose toxicity: Oral

Repeated dose subacute oral toxicity study of the test chemical was assessed for its possible toxic potential .For this purpose 28 days Sub acute study was conducted in male and female Wistar rats by oral gavage. The test animals were exposed at the concentration of 0, 200, 400 and 800 mg/kg/bw day for 28 days. As the female rats in the highest dose group showed serious weakening after 19 days of dosing the dose was reduced to 400 mgikg. The average doses for the female groups were 0, 200, 400 and 671 mg/kg b.w./day. The animals were observed for mortality, clinical sign, food consumption, body weight, clinical chemistry, organ weight, Histopathology. Significant effects in clinical chemistry organ weight and histopathology were observed at the dose concentration of 400and 800 mg/kg/bw day. No significant effect was observed at the 200 mg/kg/bw day. Therefore the No observed adverse effect level (NOAEL) was considered to be less than 200 mg/kgbw/ day in male and female wistar rats for Menthone for 28 days sub acute toxicity study by oral gavage.

Repeated dose toxicity : Inhalation

According to Annex IX of the REACH regulation, testing by the inhalation route is appropriate only if exposure of humans via inhalation is likely. Taking into account the low vapour pressure of the substance Menthone ; IUPAC name;(2R,5S)-5-methyl-2-(propan-2-yl)cyclohexan-1-one (CAS no 89-80-5) ,which is reported as 0.0002775228 mmHg at temperature 25 Deg C. Thus, exposure to inhalable dust, mist and vapour of the chemical 4-tert-butylcyclohexanol  is highly unlikely. Therefore this study is considered for waiver.

Repeated dose toxicity: Dermal

The acute dermal toxicity value forMenthone ; IUPAC name;(2R,5S)-5-methyl-2-(propan-2-yl)cyclohexan-1-one (CAS no. 89-80-5)(as provided in section 7.2.3) is >5000 mg/kg body weight. The substance was also found to be not irritating and not sensitizing to the skin. Considering this, the end point for repeated dermal toxicity is considered as waiver.

Key value for chemical safety assessment

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 publication

Qualifier:

according to guideline

Guideline:

other: Refer below principle

Principles of method if other than guideline:

Sub acute toxcity study for the test chemical was conducted on male and female Wistar SPF rats to evaluate its repeated dose toxicity

GLP compliance:

not specified

Limit test:

no

Species:

rat

Strain:

Wistar

Remarks:

SPF rats

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS- Source: Mollegaards Breeding Centre Ltd., Ejby (DK-4623 L. Skensved).- Age at study initiation: 4 weeks old when purchased- Weight at study initiation: No data- Fasting period before study: Not specified - Housing: The animals were kept in stainless steel wire cages (2 per cage)- Diet (e.g. ad libitum): The rats were fed a pelleted diet (Chow 101, Institute of Toxicology, and National Food Agency). ad libitum- Water (e.g. ad libitum): acidified water (citric acid, pH 3.5) was given ad lib.- Acclimation period:ENVIRONMENTAL CONDITIONS- Temperature (°C): 23 ± 1 ”C,- Humidity (%): 60% ± 5%- Air changes (per hr): air change 6-8 times/h,- Photoperiod (hrs): electric light from 21.00 to 09.00 hours

Route of administration:

oral: gavage

Details on route of administration:

No data

Vehicle:

soya oil

Details on oral exposure:

PREPARATION OF DOSING SOLUTIONS: The test chemical was dissolved in soya oil and used at dose level of 0, 200, 400 or 800 mg/Kg bw/day (males) and 0, 200, 400 and 671 mg/kg bw/day (females). DIET PREPARATION - Rate of preparation of diet (frequency): No data - Mixing appropriate amounts with (Type of food): No data - Storage temperature of food: No data VEHICLE - Justification for use and choice of vehicle (if other than water): Soya oil - Concentration in vehicle: 0, 200, 400 or 800 mg/Kg bw/day (males) and 0, 200, 400 and 671 mg/kg bw/day (females) - Amount of vehicle (if gavage): No data - Lot/batch no. (if required): No data - Purity: No data

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

Not specified

Duration of treatment / exposure:

28 days

Frequency of treatment:

Daily

Remarks:

0, 200, 400 or 800 mg/Kg bw/day (males) and 0, 200, 400 and 671 mg/kg bw/day (females)

No. of animals per sex per dose:

Total no of animals 80 animal0 mg/kgbw/ day- 10 male and 10 female200 mg/kgbw/ day-10 male and 10 female400 mg/kgbw/ day-10 male and 10 female800 (males)/671 (females) mg/kgbw/ day-10 male and 10 female

Control animals:

yes, concurrent vehicle

Positive control:

No data

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes DETAILED CLINICAL OBSERVATIONS: Yes BODY WEIGHT: Yes .FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: - Yes Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data available.FOOD EFFICIENCY:- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data available.WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study ): No data available.OPHTHALMOSCOPIC EXAMINATION: No data available.HAEMATOLOGY: Yes, Examinations were performed on reticulocytes in whole blood on the last day of the dosing period.CLINICAL CHEMISTRY: Yes, Concentration of bilirubin and the activity of alkaline phosphatase were determined in plasma of blood samples obtained on the last day of the dosing period.URINALYSIS: No data available.NEUROBEHAVIOURAL EXAMINATION: No data available.OTHER: No data

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, The rats were killed after 4 weeks of dosing by exsanguination in CO2-anaesthesia. A thorough autopsy was performed and the following organs were excised and weighed: kidneys, adrenals, spleen, heart, liver and brainHISTOPATHOLOGY: Yes , Samples from organs including kidneys, adrenals, spleen, heart, liver ,brain ,lung, aorta ,mesenterial lymph node, thymus, stomach, jejunum, colon, thyroid, parathyroid, pancreas, testis, ovary, uterus, spinal cord and ischiatic nerve were fixed in 10% buffered formalin, prepared for light microscopy and stainedwith haematoxylin-eosin (all), Per1 (liver) and PAS (liver). Frozen sections were prepared from the liver and stained with Oil Red O

Statistics:

Body weights, food and water consumption were compared by means of Student’s t-test. Analysis of variance was performed on haematoiogical parameters, clinical chemical parameters and absolute and relative organ weights. The mean values were compared by the method of Tukey.

Clinical signs:

effects observed, non-treatment-related

Description (incidence and severity):

The female rats in the highest dose (800 mg/kgbw/day) group showed, signs of toxic effects after 19 days of dosing. They had pale mucous membranes and showed signs of pain prevent deaths in this group, the dose was reduced to 400 mg/kg.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

4 animals died during the study due to accidental intratracheal dosing at 200 and 400 mg/kg.

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

The reduced food consumption was accompanied by a decrease in body weight gain at 800 mg/kg.

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

Food consumption was significantly reduced in the highest dose (800 mg/Kg) male group during the entire dosing period. In the females food consumption was significantly reduced in all dose groups within the first 2 weeks and in the highest dose group(800mg/Kg) also in the 3rd week. The terminal body weights in both males and females were decreased. The decrease was dose-dependent and statistically significant .

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:

effects observed, treatment-related

Description (incidence and severity):

Decrease in Creatinine level and a dose dependent increase in Alkaline phosphatase and bilirubin content in blood plasma were observed at 400and 800 mg/kg/bw day in treated group compare to control.

Urinalysis findings:

not specified

Behaviour (functional findings):

not examined

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

There was a statistically significant dose-related increase of the relative weight of the kidneys, spleen, liver and brain of the female groups at 800 mg/kg/bw day compare to control. Statistically significant dose-related increase of the relative weight of the spleen, liver and brain of the male ‘groups at 800 mg/kg/bw day compare to control. The dose-related increase of the relative brain weight is due to growth depression.

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

The terminal body weights in both males and females were decreased. The decrease was dose-dependent and statistically significant

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Histological examination revealed dose-related alterations in the brain. Cyst like space was found in the white matter of cerebellum in rats at 400and 800 mg/kg/bw day in treated group compare to control.

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Dose descriptor:

NOAEL

Effect level:

< 200 other: mg/kgbw/ day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

clinical biochemistry

clinical signs

histopathology: non-neoplastic

organ weights and organ / body weight ratios

Remarks on result:

other: No significant effect were observed at this dose level.

Critical effects observed:

not specified

System:

other: Not specified

Organ:

not specified

Treatment related:

not specified

Dose response relationship:

not specified

Relevant for humans:

not specified

Table 1: BODY WEIGHT AND RELATIVE ORGAN WEIGHTS OF RATS DOSED WITH 0, 200, 400 AND 800a mg MENTHONE/kg b.w./DAY FOR 28 DAYS

	Mg/Kg bw/day
	0	200	400	800^a
No. of animals
Female	10	9	8	10
Male	10	10	9	10
Body weight (g)
Female	187±18	176±13	168±9	166±11**
Male	286±29	258±27	243±25	234±26**
Kidneys (mg/g)
Female	7.08±0.44	7.58±0.52	7.68±0.48	7.76±0.42*
Spleen (mg/g)
Female	2.73±0.36	3.15±0.42	3.39±0.79	3.53±0.48*
Male	2.36±0.29	2.47±0.27	3.13±0.52	3.10±0.52**
Liver (mg/g)
Female	31.14±1.10	34.37±2.07	37.53±1.51	40.21±2.14***
Male	31.46±2.18	34.28±2.61	37.19±1.67	42.40±2.42***
Brain (mg/g)
Female	9.84±0.74	10.44±0.84	10.73±0.59	10.91±0.92*
Male	6.84±0.46	7.74±0.97	7.93±0.62	8.35±0.56***

Means±SD (* P<0.05, ** P<0.01; *** P<0.001).

^aDose reduced to 400 mg/kg in the female group on day 19.

 

TABLE 2: CLINICAL CHEMICAL PARAMETERS IN RATS DOSED WITH MENTHONE (n = 8/sex/group)

		Mg/Kg bw/day
		0	200	400	800^a
Creatinin (µmol/mL)	Female	38.8±7.6	62.9±7.3	59.4±5.5	50.5±7.6***
	Male	64.2±6.3	66.7±6.8	59.6±6.5	49.2±5.5***
Alkaline phosphatase (U/L)	Female	159±38	225±68	211±64	346±149**
	Male	260±55	363±178	440±120	451±144**
Bilirubin (mg/100mL)	Female	0.19±0.06	0.23±0.06	0.30±0.19	0.35±0.14***
	Male	0.13±0.06	0.20±0.06	0.26±0.05	0.44±0.19***

 

TABLE 3: NUMBER OF ANIMALS WITH HISTOLOGICAL CHANGES IN THE CEREBELLUM AFTER ADMINISTRATION OF MENTHONE FOR 28 DAYS

	Mg/Kg bw/day
	0	200	400	800^a
Female	0 (10)	0 (9)	1 (8)	7 (10)
Male	0 (10)	0 (10)	3 (9)	5 (10)

Conclusions:

The No observed adverse effect level (NOAEL) was considered to be less than 200 mg/kgbw/ day in male and female wistar rats for Menthone for 28 days sub acute toxicity study by oral gavage.

Executive summary:

Repeated dose subacute oral toxicity study of the test chemical was assessed for its possible toxic potential .For this purpose 28 days Sub acute study was conducted in male and female Wistar rats by oral gavage. The test animals were exposed at the concentration of 0, 200, 400 and 800 mg/kg/bw day for 28 days. As the female rats in the highest dose group showed serious weakening after 19 days of dosing the dose was reduced to 400 mgikg. The average doses for the female groups were 0, 200, 400 and 671 mg/kg b.w./day. The animals were observed for mortality, clinical sign, food consumption, body weight, clinical chemistry, organ weight, Histopathology. Significant effects in clinical chemistry organ weight and histopathology were observed at the dose concentration of 400and 800 mg/kg/bw day. No significant effect was observed at the 200 mg/kg/bw day. Therefore the No observed adverse effect level (NOAEL) was considered to be less than 200 mg/kgbw/ day in male and female wistar rats for Menthone for 28 days sub acute toxicity study by oral gavage.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LOAEL

200 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Data is from 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

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Link to relevant study records

Reference

Endpoint:

repeated dose toxicity: dermal, 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: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

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

Repeated dose toxicity: Oral

Repeated dose subacute oral toxicity study of the test chemical was assessed for its possible toxic potential .For this purpose 28 days Sub acute study was conducted in male and female Wistar rats by oral gavage. The test animals were exposed at the concentration of 0, 200, 400 and 800 mg/kg/bw day for 28 days. As the female rats in the highest dose group showed serious weakening after 19 days of dosing the dose was reduced to 400 mgikg. The average doses for the female groups were 0, 200, 400 and 671 mg/kg b.w./day. The animals were observed for mortality, clinical sign, food consumption, body weight, clinical chemistry, organ weight, Histopathology. Significant effects in clinical chemistry organ weight and histopathology were observed at the dose concentration of 400and 800 mg/kg/bw day. No significant effect was observed at the 200 mg/kg/bw day. Therefore the No observed adverse effect level (NOAEL) was considered to be less than 200 mg/kgbw/ day in male and female wistar rats for Menthone for 28 days sub acute toxicity study by oral gavage.

In another study, repeated dose oral toxicity study was performed to determine the toxic nature of the test chemical. The study was performed using male rats. The test chemical was dissolved in 1% methyl cellulose and use at dose level of 0 or 600 mg/kg/day.Microsomes were prepared from liver and kidneys by a differential centrifugation method. Cytochromes P-450 and b₅, NAD(P)H-cytochrome c reductase activities, heme content {estimated at 557 nm as the pyridine ferrochromogen), protein, SGPT, glucose-6-phosphatase and aminopyrine N-demethylase were determined. Oral administration of menthone (600 mg/kg per day), for 3 days resulted in a marginal increase (≈13%) in hepatic cytochrome P-450 without affecting cytochrome b₅levels. However, the hepatic cytochrome P-450 system was not affected due to test chemical treatment. Based on the observations made, the No observed adverse effect level (NOAEL) for the test chemical is considered to be 600 mg/Kg/day. However, this paper does not describe the complete details of chemical testing. Hence the NOAEL is not considered for classification.

Repeated dose toxicity : Inhalation

According to Annex IX of the REACH regulation, testing by the inhalation route is appropriate only if exposure of humans via inhalation is likely. Taking into account the low vapour pressure of the substance Menthone ; IUPAC name;(2R,5S)-5-methyl-2-(propan-2-yl)cyclohexan-1-one (CAS no 89-80-5) ,which is reported as 0.0002775228 mmHg at temperature 25 Deg C. Thus, exposure to inhalable dust, mist and vapour of the chemical 4-tert-butylcyclohexanol  is highly unlikely. Therefore this study is considered for waiver.

Repeated dose toxicity: Dermal

The acute dermal toxicity value forMenthone ; IUPAC name;(2R,5S)-5-methyl-2-(propan-2-yl)cyclohexan-1-one (CAS no. 89-80-5)(as provided in section 7.2.3) is >5000 mg/kg body weight. The substance was also found to be not irritating and not sensitizing to the skin. Considering this, the end point for repeated dermal toxicity is considered as waiver.

Based on the data available, the test chemical is not likely to classify as a toxicant as per the criteria mentioned in CLP regulation.

Justification for classification or non-classification

Based on the data available, the test chemical is not likely to classify as a toxicant as per the criteria mentioned in CLP regulation.