Gum of Cistus ladaniferus (Cistaceae) obtained from stems and leaves by extraction with alkaline solution

Endpoint summary

Description of key information

No data are available on the toxicokinetic properties of the registered substance. It is a complex mixture, which contains a large number of unknown constituents but which have different solubilities (often low) and volatilities. In addition, the physical state of such complex substance is described as a dark brown pasty mass to solid at room temperature and atmospheric pressure.

It is difficult to estimate the toxicokinetic properties of the substance based on its physico-chemical properties because no information is available on the water solubility, partition coefficient and volatility of the whole substance and information on a very limited part of the constituents is available. However,

the available evidence suggests that the substance is bioavailable via the oral and dermal routes. The substance is expected to be extensively metabolised and probably excreted in urine.

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Absorption rate - oral (%):

100

Absorption rate - dermal (%):

100

Absorption rate - inhalation (%):

100

Additional information

In accordance with the section 8.1.1 of Annex X of Regulation (EC) No 1907/2006 (REACH), the toxicokinetic profile of the substance (i.e. absorption, distribution, metabolism and elimination) was derived from the relevant available information collated in the dossier. The physical chemical characteristics, the results obtained from acute, repeated-dose, and reproductive toxicity studies on the substance, as well as information gained from genotoxicity assays were used to predict its toxicokinetic behaviour. However, the test substance is a complex mixture, which contains a large number of unknown constituents but which have different solubilities (often low) and volatilities. In addition, the physical state of such complex substance is described as a dark brown pasty mass to solid at room temperature and atmospheric pressure.

It is difficult to estimate the toxicokinetic properties of the substance based on its physico-chemical properties because no information is available on the water solubility, partition coefficient and volatility of the whole substance and information on a very limited part of the constituents is available.

 

Absorption:

Oral/GI absorption:

It is difficult to estimate the absorption of the substance based on its physico-chemical properties because no information is available on the water solubility and information on a very limited part of the constituents is available.

The substance could be absorbed in the gastro-intestinal tract by passive diffusion. This hypothese was supported by oral systemic effects observed in the combined toxicity study with the reproduction/developmental toxicity screening test performed on the registered substance in rats by dietary administration (OECD 422, Covance, 2019).

The observation of slight systemic effects indicates the oral bioavailability of the registered substance and/or its metabolites.

In light of these data, and the lack of specific information on oral absorption, the substance was assumed to be 100% bioavailable by oral route for the purposes of human health risk assessment.

 

Dermal absorption:

It is difficult to estimate the dermal absorption of the substance based on its physico-chemical properties because no information is available on

the partition coefficient and information on a very limited part of the constituents is available. The absence of effects in the actue toxicity study by dermal route probably indicates low toxicity rather than the absence of absorption.

In light of these data, the substance was conservatively assumed to be 100% bioavailable by dermal route for the purposes of human health risk assessment.

Respiratory absorption:

The potential for inhalation toxicity was not evaluated in vivo.

The vapour pressure of the test item was calculated as 471 Pa at 20.0 °C and 699 Pa at 25 °C (interpolation). These values represent the components with the highest vapour pressure. However, it don't represent the major part of the substance (UVCB).

In light of these data, and the lack of specific information on respiratory absorption, the substance was conservatively assumed to be 100% bioavailable by inhalation for the purposes of human health risk assessment.

Distribution:

There is no experimental evidence to indicate distribution. There is, however, no evidence of cumulative effects from the repeated dose oral toxicity study (OECD 422).

Metabolism:

All three in vitro genotoxicity tests showed some evidence of attenuation of cytotoxicity in the presence of S9 which may indicate biotransformation into less cytotoxic metabolites by microsomal enzymes.  

 

Excretion:

No data available.

Any substance that is not absorbed from the gastro-intestinal tract, following oral ingestion, will be excreted in the faeces.

Following dermal exposure, as the substance, that have penetrated the stratum corneum is likely to be absorbed in the blood following excretion in urine unchanged or as glucuronide and sulfate conjugates if metabolisation in the liver occurs.