Eosin Y

Eosin Y is a dye and brominated derivative of the fluorescent compound fluorescein.¹ It exists as a tautomer in aqueous solutions.^2,1 Eosin Y has minimal pH dependence at physiological pH and has commonly been used in hematoxylin and eosin (H&E) staining to stain the extracellular matrix and cytoplasmic proteins.^3,4 It displays absorption/emission maxima of 526/544 nm, respectively.⁵ It has also been used as a photoredox catalyst in organic synthesis reactions, including for cyclization and the formation of carbon-carbon or carbon-non-carbon bonds, and as a cooperative catalyst with transition metals.¹ Eosin Y (100 µM) non-selectively inhibits histone methyltransferases.⁶ Formulations containing eosin Y have been used in the screening of cervical cancer as part of the Papanicolaou (Pap) staining process.

WARNING This product is not for human or veterinary use.

1. Bosveli, A., Montagnon, T., Kalaitzakis, D., et al. Eosin: A versatile organic dye whose synthetic uses keep expanding. Org. Biomol. Chem. 19(15), 3303-3317 (2021).

2. McHedlov-Petrossyan, N.O., Vodolazkaya, N.A., Surov, Y.N., et al. 2,4,5,7-Tetranitrofluorescein in solutions: Novel type of tautomerism in hydroxyxanthene series as detected by various spectral methods. Spectrochim. Acta A Mol. Biomol. Spectrosc. 61(11-12), 2747-2760 (2005).

3. Slyusareva, E., and Gerasimova, M.A. pH-dependence of the absorption and fluorescent properties of fluorone dyes in aqueous solutions. Russ. Phys. J. 56(12), 1370-1377 (2014).

4. Fischer, A.H., Jacobson, K.A., Rose, J., et al. Hematoxylin and eosin staining of tissue and cell sections. CSH Protoc. 3(5), prot4986 (2006).

5. Seybold, P.G., Gouterman, M., and Callis, J. Calorimetric, photometric and lifetime determinations of fluorescence yields of fluorescein dyes. Photochem. Photobiol. 9(3), 229-242 (1969).

6. Okabe, J., Fernandez, A.Z., Ziemann, M., et al. Endothelial transcriptome in response to pharmacological methyltransferase inhibition. ChemMedChem 9(8), 1755-1762 (2014).