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EC number: 946-670-6
CAS number: -
See also attached document on Toxicokinetic assessment Cedarwood Texas
oil - Terpenes
evaluation of Cedarwood Texas oil distilled Terpenes - Cedrene (Type 1)
and Thujopsene (Type 2) based on existing data
indicates that an “assessment of the toxicokinetic behaviour of the
substance to the extent that can be derived from the relevant available
information” should be performed at Annex VIII level.
Cedarwood Texas oil distilled - Terpenes are substances of Unknown or
Variable composition, Complex reaction products or Biological material
(UVCB substances), or more specifically a NCS (Natural Complex
Substance). As such, the essential oil of Cedarwood Texas obtained from
the wood of Juniperus mexicana (Cupressaceae) by distillation.
range % Cedrene
range % Thujopsene
Unknown constituents non-volatile fraction
Other minor and unknown volatile constituents
Absorption, distribution, metabolism and excretion data on
Cedarwood Texas Terpenes – Cedrene (Type 1) and Thujopsene (Type 2)
itself are not available and therefore the toxicokinetic assessment is
based on the available toxicology data for Cedarwood Texas Terpenes –
Cedrene (Type 1) and Thujopsene (Type 2), as well as data for the
Information from physico chemical and toxicity studies
An overview of the relevant physicochemical parameters for Cedarwood
Texas Terpenes – Cedrene (Type 1) and Thujopsene (Type 2) is provided
Cedarwood Texas Terpenes – Cedrene (Type 1) and Thujopsene (Type 2)
202.34 - 222.37 g/mol
Min. 4.33, Max. 7.04;100 % of the NCS has aLog Kow > 4
Water solubility (mg/l)
Min.0.03, Max. 8.72; 100 % of the NCS has a water solubility < 10 mg/L.
Boiling point (°C)
Min. 239.79, Max. 280.20
6.4 Pa at 25°C. The vapour pressure of the constituents ranges from Min. 0.0184 Max. 9.37
Oral: As the molecular weight range of this UVCB is below 500,
the molecules in this UVCB are likely to be absorbed via the oral/GI
tract. Uptake throughaqueous pores or carriage of such molecules
across membranes with the bulk passage of waterin the GI tract
can be expected. Furthermore uptake by passive diffusion is likely based
on its moderate log Kow values. The oral absorption of the more highly
lipophilic constituents of this UVCB (log Kow > 4) may be more dependent
on micellar solubilisation.
Based on the previous,the substancecould be absorbed
in the human body via the oral route. This is supported by the findingsin
an OECD TG 422 feeding study that was performed with the read across
source substance Cedarwood Virginia oil, which contains the same
constituents with some variations in their concentration. The source
substance induced systemic effects such as nephropathy in male rats.
Furthermore, liver effects and reduced T4 levels were observed. These
findings confirm that systemic absorption of the constituents of the
UVCB via the gastrointestinal tract takes place.
Dermal: Based on the physico chemical properties of the
substance, its molecular weight would not exclude dermal uptake, and its
water solubility and logP value would predict low to moderate absorption
of at least a part of its constituents (ECHA guidance, 7.12, Table
R.7.12-3). No acute dermal toxicity was observed in rabbits exposed to
5000 mg/kg bw was observed in the acute dermal toxicity test performed
with the read across substance Cedarwood Virginia oil.
In order to assess the potential for dermal
absorption, the absorption of all components in this UVCB was calculated
using the IH Skinperm tool version 2.0. In the model the following input
was used as a worst-case, which resulted in the highest dermal
Instantaneous deposition: 100 mg;
Affected skin area: 1,000 cm2;
Maximum skin adherence: 3 mg/cm2 (due to the
high melting points of constituents);
Thickness of stagnant air: 10 cm;
Weight fraction: 1;
Observation time: up to total absorption or
Calculated intervals: 10,000.
The substance specific input for Skinperm was
taken from the QPRF document and Substance Identity Profile. Missing
information was taken from reliable sources such as the ECHA substance
database, the Gestis substance database, Dohsbase or Chemspider. The
following input was used.
Typical conc.(% w/w)Terpenes 1 (Cedrene)
Typical conc.(% w/w)Terpenes 2 (Thujopsene)
Water solubility (mg/L)
Max skin adh. (mg/cm2)
Weighted Dermal max absorption
Terpenes 1 (Cedrene)
Terpenes 2 (Thujopsene)
The weighted permeability of the whole UVCB, calculated using the IH
Skinperm tool was 3.03% for Terpenes 1 (Cedrene) and 2.44% for Terpenes
2 (Thujopsene). The worst case absorption number 3.03% will be used for
risk assessment. This number is corrected for the unknown and minor
constituents not taken into account in the Skinperm modelling.
Inhalation: The lipophilicity of the main constituents (log Kow
>4), and a low water solubility indicate that uptake via the lungs may
be mainly via micellular solubilisation. These physico-chemical
propertieswould also facilitate absorption directly across the
respiratory tract epithelium following aspiration.
Distribution of Cedarwood Texas Terpenes – Cedrene (Type 1) and
Thujopsene (Type 2) and its major constituents is expected based on
their relatively low molecular weights. Also distribution throughout the
body would be possible due to the low to moderate water solubility,
while the higher Log Kow range also suggests distribution into cells. A
higher intracellular concentration is expected, especially in fatty
tissues. Signs of toxicity and target organs suggest that the substance
is at least distributed to the liver and kidney.
No information on metabolism can be derived from the physicochemical
data that is available for Cedarwood Texas Terpenes – Cedrene (Type 1)
and Thujopsene (Type 2). No information on metabolism of the UVCB is
available from studies, but the main constituents of the UVCB substance;
Thujopsene, Cedrol and Cedrene α/β are known to have an (inhibitory)
effect on Cytochrome p450 enzyme activities.
Hepatic phase 1 metabolism mediated by P450 is therefore a likely
mechanism. This is expected to be followed by attachment of the phase II
polar groups in the liver before elimination. Hepatic involvement is
supported by the liver effects that were observed in the OECD TG 422
Based on the systemic renal effects observed in the OECD TG 422
read-across study, excretion is expected to take place though the
kidney. This is supported by the relatively low molecular weights.
Excretion via bile is not likely, as in the rat it has been found
that substances with molecular weights below around 300 do not tend
to be excreted into the bile (Renwick, 1994).
Some excretion via breast milk, saliva and sweat is cannot be
excluded, as some constituents of the UVCP can be regarded as
lipophilic (Log Kow > 4).
There is the potential for the more highly lipophilic constituents
of this UVCB (log P >4) to accumulate in individuals that are
frequently exposed (e.g. daily at work) to these substances. Once
exposure stops, the concentration within the body will decline at a
rate determined by the half-life of the substance (Rozman and
Data from other studies
Skin irritation / corrosivity
Cedarwood Texas oil distilled - Terpenes (Thujopsene): not irritant
Cedarwood Texas oil distilled - Terpenes (Cedrene): irritant (read-across from Cedarwood Virginia oil)
Cedarwood Texas oil distilled - Terpenes (Cedrene): not corrosive (read-across from Cedarwood Virginia oil)
Acute Oral toxicity data
Cedarwood Texas oil distilled - Terpenes LD50> 5000 mg/kg bw (read-across from Cedarwood Virginia oil)
Acute Dermal toxicity data
Skin sensitisation data
Cedarwood Texas oil distilled - Terpenes (Thujopsene): not sensitising
Cedarwood Texas oil distilled - Terpenes (Cedrene): sensitising (read-across from Cedarwood Virginia oil)
Repeated dose toxicity
Nephropathy in male rats (hyaline droplet accumulation), hepatocellular hypertrophy in female rats.(read across from Cedarwood Virginia oil)
Oral uptake expected based on information from available studies
(acute and repeated dose oral toxicity) and favourable physico
chemical parameters. Dermal absorption would be possible based on
physicochemical parameters. Relatively wide distribution and
excretion through urine expected based on low/moderate water
solubility and low molecular weight. The absorption values to be
used for hazard assessment are 100% for the inhalation route, 50%
for the oral route and 3.03% for the dermal
Jeong, Soon-Sang Kwon, Tae Yeon Kong, Ju Hyun Kim & Hye Suk Lee
(2014). Inhibitory Effects of Cedrol, β-Cedrene, and Thujopsene on
Cytochrome P450 Enzyme Activities in Human Liver Microsomes.
Journal of Toxicology and Environmental Health, Part A Vol.
77 , Iss. 22-24.
AG (1994) Toxicokinetics - pharmacokinetics in toxicology. In
Hayes,A.W. (ed.) Principles and Methods of Toxicology. Raven
Press, New York, USA, pp.103.
KK and Klaassen CD (1996) Absorption, Distribution, and
Excretion of Toxicants.In:Klaassen CD (Ed.) Cassarett and
Doull's Toxicology: The Basic Science of Poisons. McGraw-Hill,
New York, USA.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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