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ImageName1 = Safranin
IUPACName = Safranin
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Safranin (also Safranin O or basic red 2) is a biological stain used in histology and cytology. Safranin is used as a counterstain in some staining protocols, colouring all cell nuclei red. This is the classic counterstain in a Gram stain. It can also be used for the detection of cartilage [cite journal | author = Rosenberg L | title = Chemical Basis for the Histological Use of Safranin O in the Study of Articular Cartilage | journal = J Bone Joint Surg Am. | volume = 53 | issue = 1 | pages = 69–82 | year = 1971 | pmid = 4250366 | doi = | url = | issn = | format = abstract ] , mucin and mast cell granules.

Safranin typically has the chemical structure shown at right (sometimes described as dimethyl safranin). There is also trimethyl safranin, which has an added methyl group in the "ortho-" position of the lower ring. Both compounds behave essentially identically in biological staining applications, and most manufacturers of safranin don't distinguish between the two. Commercial safranin preparations often contain a blend of both types.

Safranin also used as redox indicator in analytical chemistry.


Safranines are the azonium compounds of symmetrical 2,8-dimethyl-3,7-diamino-phenazine. They are obtained by the joint oxidation of one molecule of a "para"-diamine with two molecules of a primary amine; by the condensation of "para"-aminoazo compounds with primary amines, and by the action of "para"-nitrosodialkylanilines with secondary bases such as diphenylmetaphenylenediamine. They are crystalline solids showing a characteristic green metallic luster; they are readily soluble in water and dye blue or violet. They are strong bases and form stable monacid salts. Their alcoholic solution shows a yellow-red fluorescence. Phenosafranine is not very stable in the free state; its chloride forms green plates. It can be readily diazotized, and the diazonium salt when boiled with alcohol yields aposafranine or benzene induline, C18H12N3. F. Kehrmann showed that aposafranine could be diazotized in the presence of cold concentrated sulfuric acid, and the diazonium salt on boiling with alcohol yielded phenylphenazonium salts. Aposafranone, C18H12N2O, is formed by heating aposafranine with concentrated hydrochloric acid. These three compounds are perhaps to be represented as ortho- or as para-quinones. The "safranine" of commerce is a "ortho"-tolusafranine. The first aniline dye-stuff to be prepared on a manufacturing scale was mauveine, which was obtained by Sir William Henry Perkin by heating crude aniline with potassium bichromate and sulfuric acid. Mauveine was converted to "parasafranine" (1,8-dimethyl Safranine) by Perkin in 1878 by oxidative/reductive loss of the 7-N-"para"-tolyl group. [cite journal | journal = J. Chem. Soc., Trans. | year = 1879 | volume = 35 | pages = 717–732 | doi = 10.1039/CT8793500717 | title = LXXIV.—On mauveine and allied colouring matters | author = W. H. Perkin F.R.S.]


External links

* [ Safranin O Staining Protocol]
*Safranine has recently been employed as the cationic component of a tecton used to build a porous anionic 10.1021/ja042233m)


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  • Safranin — Saf ra*nin, n. (Chem.) (a) An orange red dyestuff extracted from the saffron. [R.] (b) A red dyestuff extracted from the safflower, and formerly used in dyeing wool, silk, and cotton pink and scarlet; called also {Spanish red}, {China lake}, and… …   The Collaborative International Dictionary of English

  • Safranin — Safranīn, Anilinrosa, Pink, künstlicher Farbstoff, zuerst durch Oxydation von Mauveïn (s.d.) gewonnen, jetzt durch Oxydation von Paratoluylendiamin mit Orthotoluidin und Kondensation der Zwischenprodukte mit Anilin hergestellt, rotbraunes Pulver …   Kleines Konversations-Lexikon

  • safranin — safrànīn m <G safranína> DEFINICIJA kem. najpoznatije azijsko bojilo; crveno u vodi, u alkoholu crveno s crvenožutom fluorescencijom ETIMOLOGIJA v. šafran + in …   Hrvatski jezični portal

  • Safranin — Strukturformel Allgemeines Name Safranin T Andere Namen Safranin O 3,7 Diamino 2,8 dimethyl 5 phenyl phenaziniumchlorid …   Deutsch Wikipedia

  • Safranin T — Strukturformel Allgemeines Name Safranin T Andere Namen …   Deutsch Wikipedia

  • safranin — Polychroite Pol y*chro*ite, n. [Poly + Gr. ? color: cf. F. polychro[ i]te.] (Chem.) The coloring matter of saffron; formerly so called because of the change of color on treatment with certain acids; called also {crocin}, and {safranin}. [1913… …   The Collaborative International Dictionary of English

  • safranin — noun see safranine …   New Collegiate Dictionary

  • safranin — noun A biological stain used in histology and cytology …   Wiktionary

  • safranin O — A mixture of dimethyl and trimethylphenosafranin chloride, a basic red dye that exhibits orange metachromasia; used in histology as a nuclear stain, in microbiology as a counterstain in the Gram method …   Medical dictionary

  • safranin — n. a group of water and alcohol soluble basic dyes used to stain cell nuclei and as counterstains for Gram negative bacteria …   Medical dictionary

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