Oligo

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Genetic toxicity in silico

QSAR evaluation: negative QSAR profiling in OECD toolbox v4.1

QSAR evaluation: negative QSAR prediction by VEGA software v1.1.4.

Genetic toxicity in vitro

Ames test (OECD 471): negative with and without metabolic activation in S. typhimurium TA 1535, TA 1537, TA 100, TA 98

Gene mutation in mammalian cells (OECD 490, read across): negative in mouse lymphoma L5178Y cells with and without metabolic activation

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in mammalian cells

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Refer to analogue justification provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity, but tested up to precipitating concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Conclusions:

The read across approach is justified in the analogue justification. The target and source substances are considered unlikely to differ in their genotoxic potential. In an adequate in vitro mammalian cell gene mutation test using the thymidine kinase gene (OECD guideline 490) with the source substance Fatty acids C16-18 (even numbered), mono, di and triesters with sucrose (no CAS) no genotoxicity was found in mouse lymphoma L5178Y cells. Therefore, no mutagenic potential in mammalian cells is expected for the target substance Fatty acids C16-18(even numbered), oligoesters with sucrose (no CAS).

Reference 2

Endpoint:

genetic toxicity in vitro, other

Remarks:

: mutagenicity profiling with OECD QSAR toolbox

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

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:

1. SOFTWARE
OECD QSAR Toolbox: a Quantitative Structure-Activity Relationship model that was developed by the Laboratory of Mathematical Chemistry, Burgas, Bulgaria (http://toolbox.oasis-lmc.org).

2. MODEL (incl. version number)
OECD QSAR Toolbox version 4.1

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See “Test material information”

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See description of profilers in attached document.

5. APPLICABILITY DOMAIN
General mechanistic profilers with relevance for mutagenicity were selected.
See description of profilers in attached document.

6. ADEQUACY OF THE RESULT
The results may be used in a weight-of-evidence approach together with other information to reach a conclusion regarding the in vitro mutagenicity potential in bacteria of the test substance.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: REACH Guidance on QSARs

Deviations:

not applicable

Principles of method if other than guideline:

- Principle of test: The OECD QSAR Toolbox v4.1 is a Quantitative Structure-Activity Relationship model that was developed by the Laboratory of Mathematical Chemistry (http://toolbox.oasis-lmc.org).

GLP compliance:

no

Type of assay:

other: QSAR profiling

Key result

Species / strain:

other: QSAR in vitro mutagenicity

Genotoxicity:

negative

Additional information on results:

No general mechanistic DNA binding alert was found in any of the four constituents. Within the selected endpoint specific profilers, no alerts were found for in vitro mutagenicity, carcinogenicity, DNA alerts for AMES, CA and MNT by OASIS and Protein binding alerts for Chromosomal aberration by OASIS.

By means of the profiler in vivo mutagenicity (Micronucleus) alerts by ISS two structural alerts were identified:: “H-acceptor-path3-H-acceptor” and “Oxolane”. The first one is triggered by a multitude of different substances, and it is therefore considered as negligible.

The oxolane structural alert is described within the OECD QSAR Toolbox as follows:
Oxolane (tetrahydrofuran) moiety represents the chemical skeleton of the furanose structure of biologically important aldopentoses, such as ribose. The oxolane substructure is a common chemical feature present in an important class of antimetabolites, the nucleoside-analogues drugs. These chemicals are synthesized for therapeutic uses, such as antiviral agents (aimed at inhibiting the HIV replication in infected humans cells), or cancer chemotherapeutic agents. Induction of micronuclei was reported for various nucleoside-analogues (Phillips et al. 1991); (Palo et al. 2009). These aberrations arise presumably through the ability of the nucleoside analogues to inhibit DNA polymerase function and/or to be incorporated into DNA as fraudolent nucleoside. As an example, Cytarabine is an antineoplastic drug, especially used in the treatment of acute myeloid leukaemia. This chemical is a pyrimidine analogue, in which the ribose sugar of cytidine is replaced by arabinose moiety.
The sucrose moiety present in the target substance contains the furanose group. Indeed, the profiling of sucrose by means of the in vivo mutagenicity (Micronucleus) alerts by ISS identifies the same alerts. Using the data gathering function of the OECD QSAR Toolbox, it was found that experimental data for the micronucleus in vivo mutagenicity of sucrose were available (Tsuchimoto et al. 1981), showing no mutagenicity for this substance.

The target substance Fatty acids C16-18(even numbered), oligoesters with sucrose is composed by esters of sucrose with fatty acids. As no mutagenic effects can be identified related to the alkyl chains of the esterified fatty acids, the experimental evidence available for sucrose support the non-mutagenicity for the target substance. Moreover, the presence of alkyl chains bounded to the sucrose moiety could increase the steric hindrance of the substance, disfavouring its possible interaction with DNA.

Remarks on result:

other: no mutagenic potential based on QSAR profiling

Conclusions:

No alerts for in vitro mutagenicity were found for the majority of profilers used to assess the mutagenic potential of the four representative constituents of the UVCB substance Fatty acids C16-18(even numbered), oligoesters with sucrose using OECD QSAR toolbox v4.1 for profiling.

Reference 3

Endpoint:

genetic toxicity in vitro, other

Remarks:

: mutagenicity prediction with VEGA

Type of information:

(Q)SAR

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model, but not (completely) falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
Vega, v1.1.4, a freely available software

2. MODELS (incl. version number)
Mutagenicity (Ames test) model (CAESAR) 2.1.13
Mutagenicity (Ames test) model (SarPy/IRFMN) 1.0.7
Mutagenicity (Ames test) model (ISS) 1.0.2
Mutagenicity (Ames test) model (KNN/Read-Across) 1.0.0
Mutagenicity (Ames test) CONSENSUS model 1.0.2
Carcinogenicity model (CAESAR) 2.1.9
Carcinogenicity model (ISS) 1.0.2
Carcinogenicity model (IRFMN/Antares) 1.0.0
Carcinogenicity model (IRFMN/ISSCAN-CGX) 1.0.0

Results in all VEGA models are presented qualitatively: positive or negative.

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
See “Test material information”

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
See "Any other information of materials and methods incl. tables"

5. APPLICABILITY DOMAIN
See "Any other information of materials and methods incl. tables"

6. ADEQUACY OF THE RESULT
The results are used in a weight-of-evidence approach together with other information to reach a conclusion regarding the in vitro mutagenicity potential in bacteria of the test substance.

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

other: REACH Guidance on QSARs

Deviations:

not applicable

GLP compliance:

no

Type of assay:

other: QSAR modelling

Key result

Species / strain:

other: QSAR in vitro mutagenicity

Genotoxicity:

negative

Additional information on results:

The four (Q)SAR models evaluated the target components as “NON-Mutagenic”. The reliability of these results was in general “moderate/good” for the smallest constituents (C16 Monoester and C18 Diester), which were therefore considered as compliant or nearly compliant with the models’ applicability domain. These results are reflected by the outcomes of the CONSENSUS model, which were always negative (NON-Mutagenic), with a probability of 0.0 associated to possible positive outcomes. The two largest constituents (C18 Pentaester and C18 Octaester), on the contrary, were generally considered as out of the applicability domain. No structural alerts related to mutagenic effect were however identified in any of the constituents.

The models for carcinogenicity were also included in the evaluation. Also in this case, no structural alerts related to possible genotoxic carcinogenicity effect were identified. Furthermore, no carcinogenicity effect was predicted for any of the evaluated molecule.

Remarks on result:

no mutagenic potential (based on QSAR/QSPR prediction)

Conclusions:

The models or profilers included in VEGA QSAR prediction did not provide any results indicative for mutagenic potential of the evaluated constituents of the target substance.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

In vivo micronucleus assay (OECD 474), read across): negative in mice

Link to relevant study records

Reference

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

Refer to analogue justification provided in IUCLID section 13.

Reason / purpose for cross-reference:

read-across source

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

valid

Conclusions:

The read across approach is justified in the analogue justification. The target and source substances are considered unlikely to differ in their genotoxic potential. In an in vivo mammalian erythrocyte micronucleus test (OECD guideline 474) performed in male and female mice with the source substance Fatty acids C16-18 (even numbered), mono, di and triesters with sucrose (no CAS) no genotoxicity was found upon two oral gavage doses at 24-hour interval at 2000 mg/kg body weight. Therefore, no in vivo genotoxic potential is expected for target substance Fatty acids C16-18(even numbered), oligoesters with sucrose (no CAS).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Justification for read across

For the target substance Fatty acids C16-18(even numbered), oligoesters with sucrose (no CAS) only data on mutagenicity in bacteria are available. The assessment of its genotoxic potential was therefore based on additional studies conducted with an analogue source substance as part of a read across approach, which is in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.5. For each specific endpoint the source substance(s) structurally closest to the target substance is/are chosen for read-across, with due regard to the requirements of adequacy and reliability of the available data. Structural similarities and similarities in properties and/or activities of the source and target substance are the basis of read-across. A detailed justification for the analogue read-across approach is provided in the technical dossier (see IUCLID Section 13).

 

Genetic toxicity (mutagenicity) in bacteria in vitro

The in vitro genetic toxicity of Fatty acids C16-18(even numbered), oligoesters with sucrose (no CAS) was assessed in a bacterial reverse mutation study (Ames test), performed under GLP conditions according to OECD guideline 471(WoE, 1996). S. typhimurium strains TA 1535, TA 1537, TA 98 and TA 100 were exposed to the test substance in DMSO at concentrations up to 5000 µg/plate. No precipitation was observed. The negative and positive controls were valid. The test substance did not induce reversions in the four S. typhimurium strains, with or without metabolic activation. Based on the study results, no mutagenicity in bacteria was found.

Genetic toxicity (mutagenicity) in bacteria profiling in silico

As only four Salmonella strains were tested for bacterial mutagenicity, the target substance Fatty acids C16-18(even numbered), oligoesters with sucrose (no CAS) was further assessed for its mutagenicity potential by QSAR modelling. Four constituents of the UVCB substance, which were considered representative for the UVCB substance, were selected for evaluation by means of (Q)SAR models included in the free available OECD QSAR Toolbox v4.1 and VEGA software v1.1.4. The models or profilers included in VEGA and the OECD QSAR Toolbox did not provide any results indicative for mutagenic potential of evaluated components of the target substance. Only two alerts (“H-acceptor-path3-H-acceptor” and “Oxolane”) were identified as possibly related to micronucleus mutagenicity. H-acceptor-path3-H-acceptor is triggered by a multitude of different substances, and was therefore considered as negligible. The alert “Oxolane” resulted from the sucrose moiety of the target substance. Experimental data available in the data base of OECD QSAR Toolbox for sucrose showed no mutagenicity. Therefore this alert was also considered negligible for the target substance. Absence of mutagenic potential was also supported by the findings of the VEGA software. The four evaluated constituents were consistently predicted as “Non-Mutagenic” by the VEGA models for Mutagenicity (Ames test). Therefore following a weight of evidence approach and in good congruence with the experimental results of the Ames test, Fatty acids C16-18(even numbered), oligoesters with sucrose is considered as not mutagenic in bacteria.

Genetic toxicity (mutagenicity) in mammalian cells in vitro

An in vitro mammalian cell gene mutation study was performed with the analogue source substance Fatty acids C16 -18 (even numbered), mono, di and triesters with sucrose under GLP conditions according to OECD guideline 490 (key study, 2017). Four replicates were performed. Based on a pre-experiment, mouse lymphoma L5178Y cells were exposed for 4 h to test substance concentrations of 10, 20, 50, 100, 200, and 300 µg/mL, both with and without metabolic activation. Tetrahydrofuran (THF) was used as a solvent. Negative, solvent, and positive controls were valid. Precipitation was seen at the highest test concentration of 300 µg/mL. The test substance was not cytotoxic, nor mutagenic. In conclusion, the test substance did not induce gene mutation in mouse lymphoma cells. Based on the study results, no mutagenicity in mammalian cells was found.

In vivo cytogenicity

A micronucleus assay in bone marrow cells of ICR mice was performed with the analogue source substance Fatty acids C16-18 (even numbered), mono, di and triesters with sucrose (no CAS) according to OECD Guideline 474 under GLP conditions (key study, 2016). In a preliminary test, 3 animals each received 500 and 2000 mg/kg bw/day test substance oral by gavage, respectively. Since no systemic toxicity or cytogenicity was observed, in the main test 5 male and 5 female mice received 2000 mg/kg bw/day test substance oral by gavage on two consecutive days. 44 – 48 h after final exposure animals were euthanized, blood was collected and erythrocytes were isolated. Cells were stained with fluorescent labelled anti-CD71 antibody and propidium iodide. At least 4000 immature cells per animal were analysed by flow cytometry. No clinical signs of toxicity were observed in the animals during the study period. No test substance related change in reticulocyte fraction (% RET) and micronucleus frequency (% MN-NCE) was observed. The data indicate that the test substance is not genotoxic in mammalian bone marrow cells with respect to micronucleus induction under in vivo test conditions.

 

Overall conclusion for genetic toxicity

Only a bacterial mutagenicity study is available for the target substance Fatty acids C16-18(even numbered), oligoesters with sucrose (no CAS). Therefore QSAR evaluation (in silico assessment of mutagenicity) and analogue read-across from the analogue source substance Fatty acids C16-18 (even numbered), mono, di and triesters with sucrose (no CAS) using studies on in vitro mutagenicity in mammalian cells and in vivo cytogenicity in mice. The available results were consistently negative. Based on the available data and following the analogue read across approach, no mutagenic or clastogenic potential is expected for the target substance Fatty acids C16-18(even numbered), oligoesters with sucrose (no CAS).

Justification for classification or non-classification

According to Article 13 of Regulation (EC) No. 1907/2006 "General Requirements for Generation of Information on Intrinsic Properties of substances", information on intrinsic properties of substances may be generated by means other than tests e.g. from information from structurally related substances (grouping or read-across), provided that conditions set out in Annex XI are met. Annex XI, "General rules for adaptation of this standard testing regime set out in Annexes VII to X” states that “substances whose physicochemical, toxicological and ecotoxicological properties are likely to be similar or follow a regular pattern as a result of structural similarity may be considered as a group, or ‘category’ of substances. This avoids the need to test every substance for every endpoint". Since the analogue concept is applied to Fatty acids C16-18(even numbered), oligoesters with sucrose (no CAS), data will be generated from data for reference source substance(s) to avoid unnecessary animal testing. Additionally, once the analogue read-across concept is applied, substances will be classified and labelled on this basis.

Therefore, based on the analogue read-across approach, the available data on genetic toxicity do not meet the classification criteria according to Regulation (EC) 1272/2008 and are therefore conclusive but not sufficient for classification.