3,5-dihydroxy-2,6,6-tris(3-methylbuten-2-yl)-4-(3-methyl-1-oxobutyl)cyclohexa-2,4-dien-1-one

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

Principal key study on "Evaluation of the Mutagenic Activity of Hop Extract in the Salmonella typhimurium Reverse Mutation Assay and the Escherichia coli Reverse Mutation Assay (Plate Incorporation and Pre-Incubation Methods)" peformed in 2017 according to GLP.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Principles of method if other than guideline:

Key study: The objective of this study was to determine the potential of Hop Extract and/or its metabolites to induce reverse mutations at the histidine locus in several strains of Salmonella typhimurium (S. typhimurium; TA98, TA100, TA1535, and TA1537), and at the tryptophan locus of Escherichia coli (E. coli) strain WP2uvrA in the presence or absence of an exogenous mammalian metabolic activation system (S9).
The design of this study is based on the following study guidelines:
• OECD Guideline 471. Genetic Toxicology: Bacterial Reverse Mutation Test. (Adopted July 21, 1997).
• EC Guideline No. 440/2008. Part B: Methods for the Determination of Toxicity and other health effects, Guideline B.13/14: "Mutagenicity: Reverse Mutation Test using Bacteria”. Official Journal of the European Union No. L142, 31 May 2008.

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Hop, Humulus lupulus, ext.

EC Number:

232-504-3

EC Name:

Hop, Humulus lupulus, ext.

Cas Number:

8060-28-4

Molecular formula:

No simple molecular formula for UVCB

IUPAC Name:

Hop, Humulus lupulus, ext.

Test material form:

liquid: viscous

Remarks:

Depending on the extraction conditions and on the hop variety, the colour of the extract can vary from yellow to dark green. It is a semi-fluid paste at room temperature. The product becomes more fluid when heated.

Specific details on test material used for the study:

Key study: Hop extract. Batch no. 16/4021. Dark green/brown resin; UVCB.

Method

Target gene:

Key study: The objective of this study was to determine the potential of Hop Extract and/or its metabolites to induce reverse mutations at the histidine locus in several strains of Salmonella typhimurium (S. typhimurium; TA98, TA100, TA1535, and TA1537), and at the tryptophan locus of Escherichia coli (E. coli) strain WP2uvrA in the presence or absence of an exogenous mammalian metabolic activation system (S9).

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Metabolic activation:

with and without

Test concentrations with justification for top dose:

Key study: 1600 ug per plate. Initial range finding showed that 5000 ug per plate caused precipitation of hop extract.

Vehicle / solvent:

DMSO

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

2-nitrofluorene

sodium azide

methylmethanesulfonate

Results and discussion

Test results

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Applicant's summary and conclusion

Conclusions:

Key study: Hop Extract is not mutagenic in the Salmonella typhimurium reverse mutation assay and in the Escherichia coli reverse mutation assay.
Hop extract contains beta-acids and the closely-related alpha acids. This batch contained 15.6% beta-acids and 42.7% alpha acids.