Concrete of Rosa Damascena (Rosaceae) obtained from fresh flowers by extraction with an apolar solvent

Partition coefficient

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

partition coefficient

Data waiving:

study technically not feasible

Justification for data waiving:

other:

Justification for type of information:

The substance is a complex mixture, which contains a large number of constituents, which are mostly unkown (30-70% of the registered substance composition is unknown) but which have different solubility (often low solubility) and volatility. In addition its physical state leads to difficulties for physico-chemical testing: It is described as an orange-red wax not mobile at ambient temperature.
A feasibility studies conducted on other natural complex substances showed that standard method OECD 117 is difficult to applicate for this kind of substances due to the very low response of the test items with the HPLC detectors tested (Diode Array Detector and Mass Spectrometry) and can lead to non reliable results, i.e. the major peak(s) of a natural complex substance tested showed a logKow < 0.3 while the substance is mainly not soluble in water.
In addition, the application of OECD 123 method and the quantification of the test item in both octanol and water phases by a GC-FID analytical method was testedon other natural complex substances. However, this approach does not allow to detect the totality of the test item constituents and was not considered as appropriate to define a range of logKow for the whole substance.
Finally the standard tests for partition coefficient endpoint are considered as intended for single substances and are not appropriate for such complex substances because of the limited knowledge of composition and the physical state of the substance.

Reference 2

Endpoint:

partition coefficient

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Study period:

run on 2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with limited documentation / justification

Justification for type of information:

QSAR prediction : The values obtained on known constituents of the substance are not experimental results, however the QSAR model is recommended by the ECHA guidance document on information requirements, is well documented with regard to validation parameters according to OECD principles. Moreover, the constituents of the substance are fully characterised towards the applicability domain.

Reason / purpose for cross-reference:

reference to other study

Principles of method if other than guideline:

QSAR estimation

Partition coefficient type:

octanol-water

Type:

log Pow

Partition coefficient:

>= 1.57 - <= 13.6

Remarks on result:

other: Temperature and pH not provided (QSAR estimation)

Remarks:

Range of logKow estimated on a the known constituents of the substance

Temperature and pH values are not considered in this model.

The estimation is based on the non-ionised form of the molecule.

No Experimental Value Adjustment was made.

The molecular weight of the constituents are between 122.16 and 380.74 g/mol, hence within the estimation domain of the validation set (27.03 -991.15 g/mol), all the functional groups are included in the list of descriptors, and, the occurence of each fragment is below the maximum number in the training/validation sets (Appendix D), such as:

		Training Set		Validation Set
Fragment Descriptor & Correction Factor Descriptor	Coef	Max	Number	Max	Number
-CH3 [aliphatic carbon]	0,5473	13	1401	20	7413
-CH2-   [aliphatic carbon]	0,4911	18	1083	28	7051
=CH- or =C<  [olefinc carbon]	0,3836	10	239	10	1847
-CH [aliphatic carbon]	0,3614	16	460	23	3864
-OH   [hydroxy, aliphatic attach]	-1,4086	6	187	9	1525
Aromatic carbon	0,294	24	1790	30	8792
=CH2 [olefinic carbon]	0,5184	2	50	4	235
-O- [oxygen, one aromatic attach]	-0.4664	3	203	5	1770
ring reaction -> 1,2 -dialkyloxy	-0.5168	1	5	2	171

Conclusions:

Log Kow of known constituents of the substance, representing a limited fraction of the composition, were estimated to be between 1.57 and 13.6 (estimated by QSAR)

Executive summary:

The partition coefficient of the known constituents of the substance were estimated using the recommended QSAR model KOWWIN v1.68, based on Atom/Fragment Contribution (AFC) method. The constituents of the test item were within the applicability domain (MW, descriptors).

This range of logKow was estimated between 1.57 and 13.6 , with a standard deviation provided by the model of 0.48.

Description of key information

No range of logKow representative of the test item can be determined (neither with an experimental approach nor with an estimation approach)

Additional information

The substance is a complex mixture, which contains a large number of constituents, which are mostly unkown (30 -70% of the registered substance composition is unknown) but which have different solubility (often low solubility) and volatility. In addition its physical state leads to difficulties for physico-chemical testing: It is described as a red-orange wax.

For such complex substances, the standard tests for partition coefficient endpoint are considered as not appropriate because of the limited knowledge of composition and the physical state of the substance. Therefore no additional test has been considered.

In addition calculated values were provided on known constituents of the substance. However, only a range of logKow on a limited part of the composition of the substance can be calculated using QSAR estimations.

Therefore it is considered that no representative range of the whole test item can be determined (neither with an experimental approach nor with an estimation approach).