Phloxine

Phloxine

Names
IUPAC name Disodium 2',4',5',7'-tetrabromo-4,5,6,7-tetrachloro-3-oxospiro[2-benzofuran-1,9'-xanthene]-3',6'-diolate
Other names Cyanosin; Cyanosine; Eosine bluish; Eosine Blue; Cyanosin B; Eosin Blue; Phloxine P; Phloxin B; Eosine I Bluish; Acid red 92; C.I. 45410; D & C Red no. 28
Identifiers
CAS Number	18472-87-2 Y
3D model (Jmol)	Interactive image
ChEBI	CHEBI:87192 N
ECHA InfoCard	100.038.490
PubChem	6433718
SMILES C1=C2C(=C(C(=C1Br)[O-])Br)OC3=C(C(=C(C=C3C24C5=C(C(=C(C(=C5Cl)Cl)Cl)Cl)C(=O)O4)Br)[O-])Br.[Na+].[Na+]
Properties
Chemical formula	C20H2Br4Cl4Na2O5
Molar mass	829.63 g·mol−1
Appearance	Red to brown powder
Solubility in water	Soluble
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Phloxine B (commonly known simply as phloxine) is a water-soluble red dye used for coloring drugs and cosmetics in the United States and coloring food in Japan. It is derived from fluorescein, but differs by the presence of four bromine atoms at positions 2, 4, 5 and 7 of the xanthene ring and four chlorine atoms in the carboxyphenyl ring. It has an absorption maximum around 540 nm and an emission maximum around 564 nm. Apart from industrial use, phloxine B has functions as an antimicrobial substance, viability dye and biological stain. For example, it is used in hematoxylin-phloxine-saffron (HPS) staining to color the cytoplasm and connective tissue in shades of red.

In the presence of light, phloxine B has a bactericidal effect on gram-positive strains, such as Bacillus subtilis, Bacillus cereus, and several methicillin-resistant Staphylococcus aureus (MRSA) strains. At a minimum inhibitory concentration of 25 µM, growth is reduced by 10-fold within 2.5 hours. At concentrations of 50 µM and 100 µM, growth is stopped completely and cell counts decrease by a factor of 10⁴ to 10⁵. For humans, the Food and Drug Administration deems phloxine B to be safe up to a daily dosage of 1.25 mg/kg.