Compendium of the most significant studies with reference to properties, intake, effects.

Al-Shabib NA, Khan JM, Malik A, Rehman MT, Husain FM, AlAjmi MF, Hamdan Ali Alghamdi O, Khan A. Quinoline yellow dye stimulates whey protein fibrillation via electrostatic and hydrophobic interaction: A biophysical study. J Dairy Sci. 2021 May;104(5):5141-5151. doi: 10.3168/jds.2020-19766. 

Abstract. Amyloid fibril formation of proteins is associated with a number of neurodegenerative diseases. Several small molecules can accelerate the amyloid fibril formation in vitro and in vivo. However, the molecular mechanism of amyloid fibrillation is still unclear. In this study, we investigated how the food dye quinoline yellow (QY) induces amyloid fibrillation in α-lactalbumin (α-LA), a major whey protein, at pH 2.0....Copyright © 2021 American Dairy Science Association. 

EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP)  Scientific Opinion on the safety and efficacy of Quinoline Yellow (E104) as a feed additive for non food-producing animals  Authors    First published: 31 July 2013 Full publication history  DOI: 10.2903/j.efsa.2013.3320

Abstract. Quinoline Yellow is applied as a colourant to add colour to feedingstuffs for non food-producing animals at the maximum dose of 500 mg/kg feed. In the absence of specific data, the safe feed concentration for non foodproducing animals could be derived from an established no observed adverse effect level of a chronic rat study applying a safety factor of 100. The resulting maximum safe concentration was calculated for dogs and cats and was extrapolated to other non food-producing animals. The maximum safe concentration was 25 mg Quinoline Yellow/kg complete feed for all non food-producing animals. Since no information regarding dusting potential was available, it would be prudent to regard both the powder and the granulated forms as hazardous if inhaled. In the absence of data on irritancy and sensitisation, it would also be prudent to treat Quinoline Yellow as an irritant and skin sensitiser. Although, in principle, no efficacy data would be required for authorised food additives, if the intended effect in feed is the same as in food, evidence of an effect in feed is needed considering the variety of feed materials and the low safe level for target animals (25 mg/kg). In the absence of any information, the efficacy of Quinoline Yellow, with respect to the dose and the nature of the feedingstuffs and their processing, could not be assessed. The derived maximum safe concentration in complete feedingstuffs (25 mg/kg) was recommended as a maximum content of Quinoline Yellow.

Khan MS, Bhatt S, Tabrez S, Rehman MT, Alokail MS, AlAjmi MF. Quinoline yellow (food additive) induced conformational changes in lysozyme: a spectroscopic, docking and simulation studies of dye-protein interactions. Prep Biochem Biotechnol. 2020;50(7):673-681. doi: 10.1080/10826068.2020.1725774.

Abstract. Quinoline yellow (QY) is a synthetic yellow dye widely used as a coloring agent for various foodstuffs. In the current study, we have examined the role of QY on the aggregation propensity of hen egg-white lysozyme (HEWL) under physiological conditions. The dye induced conformational changes in HEWL leading to aggregate formation were identified by circular dichroism (CD), turbidity analysis, fluorescence measurement and microscopic (TEM) imaging. Molecular docking and molecular dynamics simulation studies were also employed to strengthen binding and aggregation results. Our results indicate that 25-100 µM of QY induces aggregation in HEWL, while lower QY concentrations (5 and 10 µM) does not have any effect on the aggregation propensity of HEWL. The kinetics of HEWL aggregation demonstrate nucleation independent aggregation of HEWL without lag phase. On the other hand, far UV-CD analysis illustrated the loss of α-helical structure with the increasing concentration of QY. TEM results also support the formation of aggregate structures in HEWL when exposed to QY. Molecular docking and simulation studies revealed that the HEWL-QY complex is stable as compared to individual entities. In silico analysis also illustrated that QY-induced aggregation of HEWL proceeds through the formation of hydrogen bonds, electrostatic (Pi-Anion) and Pi-Sulfur interactions. The above-mentioned results highlight the possible detrimental effect by food additive dyes, particularly in protein misfolding.

Wang R, Hu X, Pan J, Gong D, Zhang G. Interaction between quinoline yellow and human serum albumin: spectroscopic, chemometric and molecular docking studies. J Sci Food Agric. 2019 Jan 15;99(1):73-82. doi: 10.1002/jsfa.9144.

Abstract. ... This work shows that QY binds to HSA, affecting its structural and functional properties, and provides new insights into the binding mechanism and a comprehensive understanding of the toxicity of QY to biological processes. © 2018 Society of Chemical Industry.

Chequer FM, Venancio VP, Almeida MR, Aissa AF, Bianchi MLP, Antunes LM. Erythrosine B and quinoline yellow dyes regulate DNA repair gene expression in human HepG2 cells. Toxicol Ind Health. 2017 Oct;33(10):765-774. doi: 10.1177/0748233717715186.

Abstract. Erythrosine B (ErB) is a cherry pink food colorant and is widely used in foods, drugs, and cosmetics. Quinoline yellow (QY) is a chinophthalon derivative used in cosmetic compositions for application to the skin, lips, and/or body surface. Previously, ErB and QY synthetic dyes were found to induce DNA damage in HepG2 cells. The aim of this study was to investigate the molecular basis underlying the genotoxicity attributed to ErB and QY using the RT2 Profiler polymerase chain reaction array and by analyzing the expression profile of 84 genes involved in cell cycle arrest, apoptosis, and DNA repair in HepG2 cells. ErB (70 mg/L) significantly decreased the expression of two genes ( FEN1 and REV1) related to DNA base repair. One gene ( LIG1) was downregulated and 20 genes related to ATR/ATM signaling ( ATR, RBBP8, RAD1, CHEK1, CHEK2, TOPB1), nucleotide excision repair ( ERCC1, XPA), base excision repair ( FEN1, MBD4), mismatch repair ( MLH1, MSH3, TP73), double strand break repair ( BLM), other DNA repair genes ( BRIP1, FANCA, GADD45A, REV1), and apoptosis ( BAX, PPP1R15A) were significantly increased after treatment with QY (20 mg/L). In conclusion, our data suggest that the genotoxic mechanism of ErB and QY dyes involves the modulation of genes related to the DNA repair system and cell cycle.

Björkner B, Magnusson B. Patch test sensitization to D & C yellow No. 11 and simultaneous reaction to quinoline yellow. Contact Dermatitis. 1981 Jan;7(1):1-4. doi: 10.1111/j.1600-0536.1981.tb03949.x.

Abstract. The quinoline color D & C Yellow No. 11 was added to a standard test series. Of 88 patients tested with 1% in PEG, four showed unexplained positive test reactions. One patient had a "flare-up" reaction after 14 days. At rechallenge he reacted to a dilution down to 0.00001%. Simultaneous reaction with the chemically related commonly used food color Quinoline Yellow (E 104) suggests cross-sensitivity.