Terpene hydrocarbon alcohols, terpene processing by-products

Endpoint summary

Description of key information

The NOAEL for repeated dose toxicity of Terpenehydrocarbon alcohols 100 mg/kg bw, at maximum containing 17.45% Camphor.

This is based on read-across from Camphor, which was tested in Sage oil containing at least 7% Camphor, in an 8wk repeated dose toxicity study. The NOAEL in the Sage oil was 250 mg/kg bw, resulting a Camphor NOAEL of 17.5 mg/kg bw for 100% Camphor.

Other Terpenehydrocarbon alcohol constituents all have higher NOAELs. Terpineol multi is a representative of this group and did not show adverse repeated dose effects in a 90 -day inhalation study up to 2230 mg/m3 (OECD TG 413, Rel. 1).

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

103 mg/kg bw/day

Study duration:

subacute

Species:

rat

Organ:

not specified

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Study duration:

subchronic

Additional information

Repeated dose toxicity for Terpene hydrocarbon alcohols is derived from Camphor because this substance has the lowest NOAEL of constituents. First the repeated dose toxicity study of Camphor is summarised and the Terpineol multi supporting repeated dose toxicity via inhalation. Thereafter the read across rationale is presented.

 

Repeated dose toxicity of Camphor (as tested in Sage oil, with a Camphor content of minimally 7%)

For Camphor, data is available from an 8-week toxicity study in white rats. Groups of 5 rats were given an oral daily dose of 250, 500, 1000 and 1250 mg/kg bw Salvia oil (sage oil). which was well At 250 mg/kg bw no adverse effects were seen. At 500 mg/kg bw some convulsing was observed. At 1000 mg/kg bw mortality was seen in most animals. At 1250 mg/kg bw all animals died. The NOAEL is 250 mg/kg bw. It is assumed that the toxicity comes from Camphor in this oil. The Camphor content in the oil is 7 to 50%. Assuming the lower Camphor content the NOAEL for 100% Camphor is 17.5 mg/kg bw (250 mg/kg bw Sage oil*0.07 fraction of Camphor).

 

Terpineol multi repeated dose inhalation toxicity

A repeated dose toxicity study with Terpineol multi is available which was performed according to OECD TG 413, and in compliance with GLP criteria. In this study, Terpineol multi was administered by inhalation-aerosol to groups of Crl:CD(SD) rats (10 rats/sex/ group) by snout-only inhalation exposure at target exposure levels of 0.2, 0.6 and 2 mg/L for 6 hours per day, 5 days per week for 13 weeks. Control animals received air only. Recovery animals were similarly treated for 13 weeks followed by a 4 week off dose period. Control and high dose recovery groups were included (10/sex/group). During the study, clinical condition, body weight, food consumption, ophthalmoscopy, haematology (peripheral blood), blood chemistry, organ weight, macropathology and histopathology investigations were undertaken. The achieved levels were 101, 95 and 112% of the target concentrations of 0.2, 0.6 and 2 mg/L, respectively (achieved concentrations 0.202, 0.572 and 2.23 mg/L). MMAD: <0.52, 0.7 and 1.6 µm for achieved concentrations of 0.202, 0.572 and 2.23 mg/L, respectively. GSD: 2.99 and 1.75 for achieved concentrations of 0.572 and 2.23 mg/L, respectively. MMAD showed a general increase with increasing aerosol concentration. The MMAD for the low dose group could not be calculated, as virtually all the measurable test material was captured on the final filter stage, and the value presented is based on the cut point of the penultimate impactor stage. The mid dose groups particle size distribution values showed a bi-modal distribution with an average of 49% of the captured droplet having a MMAD below 0.52 µm. The MMAD value for the high dose group was within the ideal range (1 to 3 µm), indicating that the aerosol was respirable to the rats. The MMADs for the low and mid dose groups were below the ideal range of 1 to 3 µm. However, since the delivered aerosol was a liquid, it is likely that those inhaled droplets with an aerodynamic diameter below 1 µm would still have impacted on airway surfaces and not been exhaled. There were no treatment related deaths or effects on food consumption, blood chemistry, ophthalmoscopy, organ weights or macropathology findings. Group mean body weight gains were lower than control for males exposed to 0.202 mg/L and for both sexes exposed to 0.572 and 2.23 mg/L. In both sexes, no relationship between exposure concentration and body weight gain was observed but the decrease in mean body weight gain was statistically significant for males exposed to 2.23 mg/L. Body weights showed full recovery for animals previously exposed to 2.23 mg/L. Clinical pathology measurements following 13 weeks of exposure revealed statistically significantly lower group mean reticulocyte percentages and absolute counts for males exposed to 0.572 or 2.23 mg/L, compared to control (as low as 0.82X control). A similar effect was observed for females exposed to 2.23 mg/L (as low as 0.87X control) but this did not attain statistical significance. During Recovery Week 4, values for both sexes previously exposed to 2.23 mg/L were similar to controls. Histopathological changes related to treatment were observed in the nasal turbinates for the majority of animals given the test substance and nasal pharynx for a limited number of animals given 0.572 or 2.23 mg/L. In the nasal turbinates, minimal to slight hyperplasia of the mucous cells in the respiratory epithelium was present at all exposure levels and did not exhibit a clear dose response in terms of incidence or severity in males, although there were slightly higher incidences in females at 0.572 mg/L or 2.23 mg/L compared with females exposed to 0.202 mg/L. After 4 weeks of recovery, partial recovery was evident, in terms of the severity observed. After 13 weeks of exposures, these changes were generally not associated with an inflammatory cell infiltrate or cellular degeneration; such changes were observed in a minority of animals and were of minimal severity. After 4 weeks of recovery, degeneration and inflammation of the respiratory epithelium showed completed recovery. However, degeneration of the olfactory epithelium showed only partial recovery in terms of the incidence observed. In the nasal pharynx, minimal hyperplasia of the mucous cells was also observed but at a lower incident and severity and was only evident for animals exposed to 0.572 or 2.23 mg/L. Complete recovery from this effect was observed following the 4 week recovery period. The aforementioned changes were typically associated with chronic exposure to an irritant material and are not considered adverse at the incidence and severity seen. Therefore, the No Observed Adverse Effect Concentration (NOAEC) was considered to be ≥2.23 mg/L (2230 mg/m3).

 

The repeated dose toxicity of Terpene hydrocarbon alcohols using read across from Camphor (CAS# 76-22-2) and Terpineol multi (CAS# 8000-41-7).

 

Introduction and hypothesis for the analogue approach

Terpene hydrocarbon alcohols have the following constituent types of substances: Solely hydrocarbons-terpene type, Alcohol-type, Ketone-type and Ether-type all having a saturated or unsaturated cyclic hydrocarbon backbone. For this substance no repeated dose toxicity data are available. In accordance with Article 13 of REACH, lacking information should be generated whenever possible by means other than vertebrate animal tests, i.e. applying alternative methods such as in vitro, QSARs, grouping and read-across. For assessing the repeated dose toxicity of the Terpene hydrocarbon alcohols, the analogue approach is selected. The main constituent type is the Alcohol-type for which the repeated dose toxicity from Terpineol multi can be used for read across. There is one Ketone-type constituent, Camphor, which is more toxic, compared to other constituents and therefore the repeated dose from Camphor will be used for read across.

Hypothesis: Terpene hydrocarbon alcohols can have repeated dose toxicity similar to Camphor at maximum Camphor concentration of 17.5%. Other Terpene hydrocarbon alcohols have NOAELs similar to Terpineol multi.

Available information: The key information fromCamphoris derived from an EFSA evaluation on Camphor of 2008. In this evaluation the key information is where Camphor was tested in an 8-week toxicity study with rats in the form of Sage oil, which contained potentially 7 to 50% Camphor. Groups of 5 rats were given daily oral doses of 250, 500, 1000 and 1250 mg/kg bw Sage oil. At 250 mg/kg bw no adverse effects were seen. At 500 mg/kg bw some convulsing was observed. At 1000 mg/kg bw most animals died and at 1250 mg/kg bw 100% mortality was seen. The NOAEL for Sage oil in this study is 250 mg/kg bw. When converting this Sage oil NOAEL to 100% Camphor, the NOAEL for Camphor is 18 mg/kg bw using the 7% lowest concentration of Camphor in Sage oil.

Terpineol multi is tested via oral gavage in an OECDTG 422, which resulted in an repeated dose NOAEL of 750 mg/kg bw but also some fertility effects were seen and therefore further repeated dose toxicity and developmental toxicity was performed. Thereafter, Terpineol multi is tested via the inhalation-aerosol route according to OECD TG 413 (Rel. 1). In this study rats (10 rats/sex/ group) by snout-only inhalation exposure at target exposure levels of 0.2, 0.6 and 2 mg/L for 6 hours per day, 5 days per week for 13 weeks. Control animals received air only. No adverse effects were seen in any of the parameters and the NOAEC in this study is >=2230 mg/m3 (1250 mg/kg bw using 50 and 100% via inhalation and oral route, respectively).

Target chemical and source chemical(s)

Constituent types of the target substance and chemical structures of the source substances are shown in the data matrix, including physico-chemical properties and toxicological information, thought relevant for repeated dose oral toxicity.

Purity / Impurities

Constituent types of the target substance are covered by the presented constituent types, there are no other constituent that impacts the repeated dose toxicity.

Analogue approach justification

According to Annex XI 1.5 read across can be used to replace testing when the similarity can be based on a common backbone and a common functional group. When using read across the result derived should be applicable for C&L and/or risk assessment and it should be presented with adequate and reliable documentation, which is presented below.

Analogue selection: For the Terpene hydrocarbon alcohols for repeated dose toxicity Camphor is selected because for this constituent repeated dose toxicity information showing the lower NOAEL compared to information from other constituent type e.g. Alcohol-type of which Terpineol multi is a representative. This information covers the repeated dose endpoint.

Structural similarities and differences: Terpene hydrocarbon alcohols contain a.o. the Ketone-type of which Camphor is the representative. Terpene hydrocarbon alcohols almost all have a similar hydrocarbon backbone with an alcohol as a functional group. The secondary alcohols in this group can be oxidised to a ketone but it is more likely that the ketone is reduced to a secondary alcohol to give handles for further processing. The Terpene hydrocarbon constituents other than Camphor can be well represented by Terpineol multi because this substance contains a variety of secondary and tertiary alcohols.

Toxico-kinetic:All Terpene hydrocarbon alcohols are absorbed somewhat similar via all routes based on the similarities in molecular weight and physico-chemical properties and Camphor and Terpineol multi are no exception.

Metabolism: Terpene hydrocarbon alcohols metabolites result in similar metabolites as those from Camphor and Terpineol Multi. The first metabolic step will result in primary, secondary or tertiary alcohols if these are not already constituents as such. Thereafter these metabolites will be further oxidised e.g. the primary alcohols can turn into acids and excreted as such or will be conjugated. The secondary and tertiary alcohols can be conjugated as such. They can also be conjugated with alpha-2 u globulin and as such be transported to the kidneys. This route is known to occur in male rats because the alpha-2u globulin sediments in the kidney and cause alpha-hydrocarbon nephropathy.

The key feature for initiation this binding to the alpha2u globulin is that the substance has a lipophilic hydrocarbon backbone and at least one hydrogen donor (alcohol) to bind to this proton and thus globulin. Therefore hydrocarbons as such (Limonene), secondary (Borneol) and tertiary alcohols, ketones that can be reduced to alcohols are susceptible to binding (Borghoff et al., 1991).

Toxico-dynamics: For Terpene hydrocarbons alcohols the Camphor constituent is the key toxicant, because repeated dose toxicity shows that the Camphor NOAEL, based on neurotoxicity, is much lower compared to Terpineol-multi. There other Terpene hydrocarbon alcohols constituents have toxicity similar to Terpineol multi. Terpineol multi showing no adverse effects up to the limit dose of 2230 mg/m3 or when converted to the oral route 1250 mg/kg bw.

Conversion of the NOAEL from Sage oil to Terpene hydrocarbon alcohols: Conversion is needed based on the Terpene hydrocarbon alcohol concentration of Camphor compared to the concentration of Camphor in Sage oil, which was the tested substance.

In Sage oil containing at least 7% Camphor, the NOAEL is 250 mg/kg bw. Assuming that Camphor is the key toxicant 100% Camphor NOAEL would be 18 mg/kg bw (250*0.07). Terpene hydrocarbon alcohols contain maximally 17.45% Camphor and therefore the NOAEL of the Terpene hydrocarbons using Camphor is 103 mg/kg bw (18/0.1745).

Other Terpene hydrocarbon alcohol constituents all have higher NOAELs. Terpineol multi is a representative of this group and did not show adverse repeated dose effects up to 750 mg/kg bw and in a follow up 90 -day inhalation study up to 2230 mg/m3 (OECD TG 413, Rel. 1).

Uncertainty of the prediction: There are no other uncertainties not already addressed above.

Data matrix

The relevant information on physico-chemical properties and toxicological characteristics are presented in the Data Matrix.

Conclusions on repeated dose toxicity for hazard and risk assessment

For Terpene hydrocarbon alcohols no repeated dose toxicity information is available but for some constituents such information is present, which can be used for read across. When using read across the result derived should be applicable for C&L and/or risk assessment, cover an exposure period duration comparable or longer than the corresponding method and be presented with adequate and reliable documentation. This documentation is presented in the current text. The key constituent for repeated dose toxicity is Camphor, in view of its toxicity seen inan 8-week toxicity study with Sage oil. The converted NOAEL 103 mg/kg bw (NOAEL in Sage oil is 250 mg/kg bw containing at least 7% Camphor converted to Terpene hydrocarbon alcohols containing maximally 17.45% Camphor. The oral and inhalation NOAELs of Terpineol multi, representing the other constituents are >=750 mg/kg bw and 2230 mg/m3 (or 1250 mg/kg bw when converted to the oral route using the same absorption percentages for both routes).

Final conclusion: For the Terpene hydrocarbon alcohols the NOAEL is 103 mg/kg bw.

 

 

Data matrix supporting the Terpene hydrocarbon alcohol repeated dose toxicity assessment by using read acrossfrom Camphor and Terpineol multi.

Terpene hydrocarbon alcohols	Terpineol hydrocarbon alcohols	Camphor	Terpineol multi
	Target	Source	Supporting source
Structure	Not applicable		(α-Terpineol)   (γ-Terpineol)
CAS	Not applicable	76-22-2	8000-41-7 (generic CAS no)
EC No.	945-149-0	200-945-0	232-268-1
Reach registration	2018	Registered	Registered
Molecular weight	136-154
Phys-chem properties
Appearance	Liquid	Solid	Liquid
Vp (Pa)	51.9 (10-52, exp)	87 (ECHA site)	6.48 (exp. α-Terpineol)
Log Kow	3.3-5.5; IFF	2.4 (ECHA site)	2.6 (α-Terpineol, IFF)
Identity, Constituent type (%)	100%	Mono constituent	Multi constituent
Solely hydrocarbons
Limonene type	0-15
Alcohol type			>80
Tertiary alcohols	40-90
Secondary alcohols	7-40
Ketone type	-
Camphor-Type	0-17%	> 80
Ether type
Cineol type	<10%-
Aromatic ether type	<10%
Human health
Repeated dose, oral, sub-acute: NOAEL mg/kg bw	103* (Read across from Camphor)	18 (8 wk oral repeated dose toxicity)	->=750 (OECD TG 422)
Repeated dose, inhalation, sub-chronic NOAEC in mg/m3)	Read across for other than Camphor constituents		≥2230 (OECD TG 413)

* Recalculated based on a NOAEL of Sage oil containing at least 7% Camphor, which is 250 mg/kg bw. Assuming that Camphor is the key toxicant 100% Camphor NOAEL would be 18 mg/kg bw (250*0.07). Terpene hydrocarbon alcohols contain maximally 17.45% Camphor and therefore the NOAEL of the Terpene hydrocarbons using Camphor is 103 mg/kg bw (18/0.1745).

References:

Belsito et al. A toxicologic and dermatologic assessment of cyclic and non-cyclic terpene alcohols when used as fragrance ingredients. Food and Chemical Toxicology. 46 (2008a) S1-71.

 

Borghoff, S.J., Miller, A.B., Bowen, J.P. and Swenberg, J.A., 1991, Characteristics of chemical binding to alph2u-globulin in vitro-Evaluation structure-acitivity relationships, Toxicol. Appl.Pharmacol. , 107, 228-238.

 

Camphor in flavourings and other food ingredients with flavouring properties, 2008, Scientific opinion of the Panel on Food Additives, Flavourings, Processing Aids and Materials in contact with Food (AFC) on a request from the Commission on Camphor in flavourings and other food ingredients with flavouring properties. The EFSA Journal 729, 1-15,http://www.efsa.europa.eu/sites/default/files/scientific_output/files/main_documents/729.pdf

 

 

Justification for classification or non-classification

Based on the absence of adverse effects >100 mg/kg bw in a reliable repeated dose toxicity study, the substance does not need to be classified for repeated dose toxicity by the oral route according to EU CLP (EC No. 1272/2008 and its amendments).