Regulatory withdrawal after toxicological review
When the EU updated its food colour rules in Directive 94/36/EC, orchil was among the substances removed from the permitted list. The Scientific Committee on Food concluded, based on its evaluation of available toxicological data, that the evidence was insufficient to maintain the colour's authorisation. The specific toxicological concerns that prompted withdrawal have not been published in detail in the public domain. Because the removal was driven by a data gap rather than a demonstrated hazard, no IARC classification or specific harm endpoint was assigned.
Orchil was deleted from the EU positive list of permitted food colours in Directive 94/36/EC, alongside seven synthetic colours, on the basis of the Scientific Committee on Food's evaluation of toxicological data.
1994RegulatoryNATCOL (Natural Food Colours Association) analysis of Directive 94/36/EC; European Parliament and Council Directive 94/36/EC of 30 June 1994 on colours for use in foodstuffs
Orcein is not listed in Annex II of the UK assimilated version of EU Regulation 1333/2008, which sets out the positive list of permitted food additives. The UK FSA approved-additives list stops at E180 (Litholrubine BK) for the colour category; E182 does not appear.
RegulatoryUK Food Standards Agency approved additives and E numbers list; UK assimilated Regulation 1333/2008 (Annex II)
Early laboratory research on orcein derivatives and Alzheimer's disease
Researchers at the Max Delbruck Center in Berlin screened natural compounds for potential use against neurodegenerative disease and identified orcein as a candidate. A derivative compound called O4, structurally related to one of the phenoxazone components of orcein, was found in laboratory cell-based assays to accelerate the conversion of small toxic amyloid-beta aggregates into larger, apparently less harmful fibrils. This research is early-stage: it was conducted in cell culture and has not been tested in animals or humans as a therapeutic. It does not change E182's regulatory status as a prohibited food additive.
Orcein and a related phenoxazone derivative O4 promoted conversion of small amyloid-beta oligomers into larger beta-sheet-rich fibrils in laboratory cell-based assays, reducing the toxicity of those oligomers to cultured neurons.
2012LabBieschke J et al., Nature Chemical Biology, Max Delbruck Center for Molecular Medicine, Berlin