title: The food colorant erythrosine is a promiscuous protein-protein interaction inhibitor.
abstract: Following our observation that erythrosine B (FD&C Red No. 3) is a relatively potent inhibitor of the TNF-R-TNFα and CD40-CD154 protein-protein interactions, we investigated whether this inhibitory activity extends to any other protein-protein interactions (PPI) as well as whether any other approved food colors possess such inhibitory activity. We found erythrosine, a poly-iodinated xanthene dye, to be a non-specific promiscuous inhibitor of a number of PPIs within the tumor necrosis factor superfamily (TNF-R-TNFα, CD40-CD154, BAFF-R-BAFF, RANK-RANKL, OX40-OX40L, 4-1BB-4-1BBL) as well as outside of it (EGF-R-EGF) with a remarkably consistent median inhibitory concentration (IC(50)) in the 2-20 μM (approximately 2-20mg/L) range. In agreement with this, erythrosine also showed cellular effects including clear cytotoxic effects around this concentration range (IC₅₀≈50 μM). Among the seven FDA-approved food colorants, only erythrosine showed consistent PPI inhibitory activity in the sub-100 μM range, which might also explain (at least partially) why it also has the lowest approved acceptable daily intake (ADI) (0.1 mg/kg body weight/day). Among a number of xanthene structural analogs of erythrosine tested for activity, rose Bengal, a food colorant approved in Japan, showed similar, maybe even more pronounced, promiscuous inhibitory activity, whereas fluorescein was inactive and gallein, phloxine, and eosin were somewhat active in some of the assays.
authors.affiliation: Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
authors.forename: Lakshmi
authors.initials: L
authors.lastname: Ganesan
authors.forename: Emilio
authors.initials: E
authors.lastname: Margolles-Clark
authors.forename: Yun
authors.initials: Y
authors.lastname: Song
authors.forename: Peter
authors.initials: P
authors.lastname: Buchwald
mesh_terms: D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004923:Erythrosine / Q000378:metabolism* / Q000494:pharmacology; D005505:Food Coloring Agents / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D022423:Myeloid Cells / Q000187:drug effects / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D054730:Protein Interaction Domains and Motifs / Q000187:drug effects / Q000502:physiology*; D012395:Rose Bengal / Q000378:metabolism / Q000494:pharmacology; D000079424:Tumor Necrosis Factor Inhibitors; D048069:Tumor Necrosis Factors / Q000378:metabolism
chemical_list: D005505:Food Coloring Agents; D000079424:Tumor Necrosis Factor Inhibitors; D048069:Tumor Necrosis Factors; D012395:Rose Bengal; D004923:Erythrosine