are a family of compounds characterized by an intense absorption and fluorescence that has been widely employed for a variety of technological applications [1-5].
Stephenson, "Fluorescent probes and switches based on the xanthene dyes
rhodamine and fluorescein," vol.
Therefore, the photodynamic efficiency of four xanthene dyes
(Rose Bengal, erythrosin B, eosin Y, and fluorescein) was determined in the present study by comparing their medium inhibitory concentration ([IC.sub.50]) values in HEp2 cells, their photodynamic activity using uric acid as a chemical dosimeter, and their octanol-buffer partition coefficient (log P).
Dorosz, "The xanthene dyes
doped PMMA microspheres for optical sensor applications," in Proceedings of the 16th Conference on Optical Fibers and Their Applications, Poland, September 2015.
They are: Erythrosin included in the class of xanthene dyes
; Blue indigotine included in the indigotin class of dyes, Patent Blue V, Fast Green and Brilliant Blue in class of triphenylmethane dyes, Bordeaux Red, Ponceau 4R, Red 40, Azorubine, Tartrazine Yellow and Sunset Yellow, included in the class of azo dyes (POLONIO; PERES, 2009).
Lavis, "Facile and general synthesis of photoactivatable xanthene dyes
," Angewandte Chemie--International Edition, vol.
Ethyl eosin, the dye, is bleached like the typical xanthene dyes
during the photoinitiation process .
, such as eosin Y, exhibit different tautomeric structures with different protolytic forms, either proton "on" or "off" depending on pH as illustrated in Figure 2 .
Phloxine B and Eosin Yellow are halogenated photoactive xanthene dyes
, that are FDA approved for use in human cosmetics and drugs.
These include naturally occurring molecules such as chiorophylls, porphyrins, phthalocyanines, flavins, thiazine dyes, acridine dyes, anthraquinone dyes, xanthene dyes
, hypercin, tetracyclines, sulfanilamides, psoralens, nalidixic acid, coal tar derivatives, chlorpromazines and aminobenzoic acid derivatives, to name but a few.
Among synthetic dyes most used by the food market are erythrosine, included in the class of xanthene dyes
, and brilliant blue, classified as a triphenylmethane dye (BRASIL, 2005).
Therefore, sufficient dye content is necessary, bearing in mind that the typical xanthene dyes
are bleached during the photo-initiation process .