Neutral red

Solid Neutral Red

Neutral Red Aqueous Solution

Names

IUPAC name

N²,N²,7-Trimethylphenazine-2,8-diamine—hydrogen chloride (1/1)

Other names

3-Amino-7-dimethylamino-2-methylphenazine hydrochloride
Toluylene red

Identifiers

CAS Number

553-24-2^Y

3D model (JSmol)

Interactive image

ChEBI

CHEBI:86370^N

ChemSpider

10634^Y

ECHA InfoCard

100.008.215

EC Number

209-035-8

PubChem CID

11105

UNII

261QK3SSBH

CompTox Dashboard (EPA)

DTXSID90883440

InChI

InChI=1S/C15H16N4.ClH/c1-9-6-13-15(8-11(9)16)18-14-7-10(19(2)3)4-5-12(14)17-13;/h4-8H,16H2,1-3H3;1H^Y
Key: PGSADBUBUOPOJS-UHFFFAOYSA-N^Y
InChI=1/C15H16N4.ClH/c1-9-6-13-15(8-11(9)16)18-14-7-10(19(2)3)4-5-12(14)17-13;/h4-8H,16H2,1-3H3;1H
Key: PGSADBUBUOPOJS-UHFFFAOYAB

SMILES

Cl.n1c3c(nc2c1cc(c(c2)N)C)cc(N(C)C)cc3

Properties

Chemical formula

C₁₅H₁₇N₄

Molar mass

288.78 g/mol

Melting point

290 °C (554 °F; 563 K)

Hazards

GHS labelling:

Pictograms

Signal word

Danger

Hazard statements

H301, H315, H319, H335, H341

Precautionary statements

P201, P202, P261, P264, P270, P271, P280, P281, P301+P310, P302+P352, P304+P340, P305+P351+P338, P308+P313, P312, P321, P330, P332+P313, P337+P313, P362, P403+P233, P405, P501

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

N verify (what is ^YN ?)

Infobox references

Chemical compound

Neutral red (pH indicator)
below pH 6.8		above pH 8.0
6.8	⇌	8.0

Neutral red (toluylene red, Basic Red 5, or C.I. 50040) is a eurhodin dye used for staining in histology. It stains lysosomes red.^[1] It is used as a general stain in histology, as a counterstain in combination with other dyes, and for many staining methods. Together with Janus Green B, it is used to stain embryonal tissues and supravital staining of blood. Can be used for staining Golgi apparatus in cells and Nissl granules in neurons.

In microbiology, it is used in the MacConkey agar to differentiate bacteria for lactose fermentation.

Neutral red can be used as a vital stain.^[2] The Neutral Red Cytotoxicity Assay was first developed by Ellen Borenfreund in 1984. In the Neutral Red Assay live cells incorporate neutral red into their lysosomes. As cells begin to die, their ability to incorporate neutral red diminishes. Thus, loss of neutral red uptake corresponds to loss of cell viability.^[3] The neutral red is also used to stain cell cultures for plate titration of viruses.

Neutral red is added to some growth media for bacterial and cell cultures. It usually is available as a chloride salt.

Neutral red acts as a pH indicator, changing from red to yellow between pH 6.8 and 8.0.

References

^ Winckler, Jürgen (1973). Vitalfärbung von Lysosomen und anderen Zellorganellen der Ratte mit Neutralrot [Vital staining of lysosomes and other cell organelles of the rat with Neutral red]. Progress in Histochemistry and Cytochemistry (in German). Vol. 6 (3). Gustav Fischer Verlag. pp. 1–91. doi:10.1016/S0079-6336(74)80001-X. ISBN 3-437-10353-9. PMID 4142096.
^ Repetto, Guillermo; del Peso, Ana; Zurita, Jorge L. (2008). "Neutral red uptake assay for the estimation of cell viability/cytotoxicity". Nature Protocols. 3 (7): 1125–1131. doi:10.1038/nprot.2008.75. PMID 18600217. S2CID 24676983.
^ Borenfreund, Ellen; Puerner, James A. (1984). "A simple quantitative procedure using monolayer cultures for cytotoxicity assays (HTD/NR90)". Journal of Tissue Culture Methods. 9 (1): 7–9. doi:10.1007/BF01666038.

Other references

Borenfreund, Ellen; Puerner, James A. (1985). "Toxicity determined in vitro by morphological alterations and neutral red absorption". Toxicology Letters. 24 (2–3): 119–124. doi:10.1016/0378-4274(85)90046-3. PMID 3983963.
Borenfreund, E.; Babich, H.; Martin-Alguacil, N. (1988). "Comparisons of two in vitro cytotoxicity assays—The neutral red (NR) and tetrazolium MTT tests". Toxicology in Vitro. 2 (1): 1–6. doi:10.1016/0887-2333(88)90030-6. PMID 20702351.