Difference between revisions of "Methylene blue" - New World Encyclopedia
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| [[IUPAC nomenclature|Chemical name]] | | [[IUPAC nomenclature|Chemical name]] | ||
| − | | 3,7-bis(Dimethylamino)-<br /> | + | | 3,7-bis(Dimethylamino)-<br />phenothiazin-5-ium chloride<br />Tetramethyl thionine |
|- | |- | ||
| − | | [[ | + | | [[Empirical formula]] |
| − | | {{{formula|C<sub>16</sub>H<sub>18</sub> | + | | {{{formula|C<sub>16</sub>H<sub>18</sub>CIN<sub>3</sub>S}}} |
|- | |- | ||
| [[Molecular mass]] | | [[Molecular mass]] | ||
| − | | {{{mol_mass|319. | + | | {{{mol_mass|319.86}}} g/mol |
|- | |- | ||
| [[CAS registry number|CAS number]] | | [[CAS registry number|CAS number]] | ||
| Line 40: | Line 40: | ||
==Uses== | ==Uses== | ||
===Chemistry=== | ===Chemistry=== | ||
| − | Methylene blue is widely used a [[redox indicator]] in [[analytical chemistry]]. | + | Methylene blue is widely used a [[redox indicator]] in [[analytical chemistry]] meaning that it indicates the presence or absence of oxygen. Oxygen-rich environments are said to be "oxidizing." Oxidizing chemicals, such as oxygen and chlorine, strip electrons away from atoms of other elements. Chemical elements that have such a strong attraction for electrons that they can "rip" electrons away from other types of atoms are known as oxidizing agents, and are very useful in chemistry. Methylene blue indicates the presence of oxidizing agents because it is oxidized itself by these compounds. When electrons are stripped from methylene blue, the resulting molecule imparts a blue color to the solution—giving a clear sign of a chemical change. <ref>http://www.americanchemistry.com/s_chlorine/sec_content.asp?CID=1251&DID=4729&CTYPEID=113</ref>The redox properties can be seen in a classical demonstration of chemical kinetics in general chemistry, the "blue bottle" experiment. Typically, a solution is made of dextrose, methylene blue, and sodium hydroxide. Upon shaking the bottle, oxygen oxidizes methylene blue, and the solution turns blue. The dextrose will gradually reduce the methylene blue to its colorless, reduced form. Hence, when the dissolved oxygen is entirely consumed, the solution will turn colorless. <ref>http://www.cci.ethz.ch/experiments/methylen/en/stat.html</ref>Methylene blue is also used to make the reaction between Fehling's solution and reducing sugars more visible. <ref>http://www.starch.dk/isi/methods/27DE.htm</ref> |
| − | Methylene blue is also used to make the reaction between | ||
===Biology=== | ===Biology=== | ||
| − | + | Methylene blue is commonly used by biologists as a dye that assists in the identification of bacteria. Because bacteria are practically colorless, adding a drop or two of methylene blue to a microscope slide enables the biologists to see bacterial shapes and structures. Dyes like methylene blue (referred to as stains in biology) work by binding to biological tissues as a result of chemical attractions. Methylene blue is at its deepest shade of blue when in contact with acids, which makes it very useful in the identification of nucleic acids, like DNA and RNA.<ref>http://www.americanchemistry.com/s_chlorine/sec_content.asp?CID=1252&DID=4730&CTYPEID=113</ref> It can also work as an alternative to the chemical crystal violet in [[Bacteria|cellular structure|gram's staining procedures]]. <ref>http://www.eng.umd.edu/~nsw/ench485/lab9b.htm</ref> As a result of this attraction to nucleic acids, methylene blue has also been used in procedures such as northern blotting/ northern hybridization (which is used for the detection of specific RNA sequences), in order to visualize RNA.<ref>http://wheat.pw.usda.gov/~lazo/methods/iubio/northgel.html</ref> In addition, methylene blue is used as a safer alternative for another chemical called ethidium bromide (normally used in the visualization of DNA on gels in blotting procedures [[Antibody|western blot]]. This is because ethidium bromide is a potent carcinogen and mutagen, and also because the short-length UV light that is required for ethidium bromide to fluroresce (and thereby aid in visualizing the DNA) can cause unwanted mutations in the DNA sample itself. Drawbacks of using methylene blue as a replacement are that it is less sensitive than ethidium bromide, and also fades rapidly after staining. This makes methylene blue an unideal replacement (though suitable for school contexts, due to it's less toxic nature). <ref>http://www.bioscience-explained.org/EN1.2/schollar.html</ref> | |
| − | + | Methylene blue has also been used as a way to obtain a quick estimate of the percentage of viable cells in a yeast sample, since viable yeast cells contain an enzyme that decolorizes methylene blue, whereas dead cells do not. As a result, when cells from a yeast are suspended in the dye, it penetrates all the cells, and leaves the dead cells blue, and the living cells unstained. Despite this, it must be noted that this method simply indicates whether an enzyme is present in the yeast cells (not whether the cells are incapable of dividing), and therefore is less accurate than other methods, and should be used to simply provide a rapid estimate. <ref>http://www.wfcc.info/tis/info2.html</ref> | |
| − | |||
===Medicine=== | ===Medicine=== | ||
Revision as of 02:23, 20 July 2007
| Methylene blue | |
|---|---|
 
| |
| Chemical name | 3,7-bis(Dimethylamino)- phenothiazin-5-ium chloride Tetramethyl thionine |
| Empirical formula | C16H18CIN3S |
| Molecular mass | 319.86 g/mol |
| CAS number | [61-73-4] |
| EC number | 200-515-2 |
| Density | ? g/cm³ |
| Melting point | 100 °C |
| Boiling point | Decomposes |
| SMILES | CN(C)c3ccc2nc1ccc(N(C) C)cc1[s+]c2c3.[Cl-] |
| Disclaimer and references | |
Methylene blue is a heterocyclic aromatic chemical compound with molecular formula: C16H18ClN3S. It has many uses in a range of different fields, such as biology or chemistry. At room temperature it appears as a solid, odorless, dark green powder, that yields a blue solution when dissolved in water. Methylene blue should not be confused with methyl blue, another histology stain, new methylene blue, nor with the methyl violets often used as pH indicators.
Uses
Chemistry
Methylene blue is widely used a redox indicator in analytical chemistry meaning that it indicates the presence or absence of oxygen. Oxygen-rich environments are said to be "oxidizing." Oxidizing chemicals, such as oxygen and chlorine, strip electrons away from atoms of other elements. Chemical elements that have such a strong attraction for electrons that they can "rip" electrons away from other types of atoms are known as oxidizing agents, and are very useful in chemistry. Methylene blue indicates the presence of oxidizing agents because it is oxidized itself by these compounds. When electrons are stripped from methylene blue, the resulting molecule imparts a blue color to the solution—giving a clear sign of a chemical change. [1]The redox properties can be seen in a classical demonstration of chemical kinetics in general chemistry, the "blue bottle" experiment. Typically, a solution is made of dextrose, methylene blue, and sodium hydroxide. Upon shaking the bottle, oxygen oxidizes methylene blue, and the solution turns blue. The dextrose will gradually reduce the methylene blue to its colorless, reduced form. Hence, when the dissolved oxygen is entirely consumed, the solution will turn colorless. [2]Methylene blue is also used to make the reaction between Fehling's solution and reducing sugars more visible. [3]
Biology
Methylene blue is commonly used by biologists as a dye that assists in the identification of bacteria. Because bacteria are practically colorless, adding a drop or two of methylene blue to a microscope slide enables the biologists to see bacterial shapes and structures. Dyes like methylene blue (referred to as stains in biology) work by binding to biological tissues as a result of chemical attractions. Methylene blue is at its deepest shade of blue when in contact with acids, which makes it very useful in the identification of nucleic acids, like DNA and RNA.[4] It can also work as an alternative to the chemical crystal violet in cellular structure|gram's staining procedures. [5] As a result of this attraction to nucleic acids, methylene blue has also been used in procedures such as northern blotting/ northern hybridization (which is used for the detection of specific RNA sequences), in order to visualize RNA.[6] In addition, methylene blue is used as a safer alternative for another chemical called ethidium bromide (normally used in the visualization of DNA on gels in blotting procedures western blot. This is because ethidium bromide is a potent carcinogen and mutagen, and also because the short-length UV light that is required for ethidium bromide to fluroresce (and thereby aid in visualizing the DNA) can cause unwanted mutations in the DNA sample itself. Drawbacks of using methylene blue as a replacement are that it is less sensitive than ethidium bromide, and also fades rapidly after staining. This makes methylene blue an unideal replacement (though suitable for school contexts, due to it's less toxic nature). [7] Methylene blue has also been used as a way to obtain a quick estimate of the percentage of viable cells in a yeast sample, since viable yeast cells contain an enzyme that decolorizes methylene blue, whereas dead cells do not. As a result, when cells from a yeast are suspended in the dye, it penetrates all the cells, and leaves the dead cells blue, and the living cells unstained. Despite this, it must be noted that this method simply indicates whether an enzyme is present in the yeast cells (not whether the cells are incapable of dividing), and therefore is less accurate than other methods, and should be used to simply provide a rapid estimate. [8]
Medicine
Owing to its reducing agent properties, methylene blue is employed as a medication for the treatment of methemoglobinemia, which can arise from ingestion of certain pharmaceuticals or broad beans. Basically, methylene blue acts to reduce the heme group from methemoglobin to hemoglobin, however since methylene blue is toxic, any methemoglobinemia treatment with this substance should be strictly evaluated by a doctor.
Methylene blue also blocks accumulation of cyclic guanosine monophosphate (cGMP) by inhibiting the enzyme guanylate cyclase: this action results in reduced responsiveness of vessels to cGMP-dependent vasodilators like nitric oxide and carbon monoxide.
Methylene blue is used in endoscopic polypectomy as an adjunct to saline or epinephrine, and is used for injection into the submucosa around the polyp to be removed. This allows the submucosal tissue plane to be identified after the polyp is removed, which is useful in determining if more tissue needs to be removed, or if there has been a high risk for perforation. Methylene blue is also used as a dye in chromoendoscopy, and is sprayed onto the mucosa of the gastrointestinal tract in order to identify dysplasia, or pre-cancerous lesions.
Methylene blue was used at the end of the century as a successful treatment for malaria. It disappeared as an anti-malarial during the wars in Asia, as U.S. soldiers disliked its two inevitable, fully reversible side effects: green urine and blue sclera. Interest in its use has recently been revived,[9] especially because it is very cheap. Several clinical trials are in progress, trying to find a suitable drug combination. Initial attempts to combine methylene blue with chloroquine were disappointing;[10] however, more recent attempts have appeared more promising.
Since its reduction potential is similar to that of oxygen and can be reduced by components of the electron transport chain, large doses of methylene blue are sometimes used as an antidote to cyanide poisoning.
Methylene blue is probably a monoamine oxidase inhibitor, and if infused intravenously at doses exceeding 5 mg/kg, may precipitate serious serotonin toxicity, serotonin syndrome, if combined with any selective serotonin reuptake inhibitors (SSRIs) or other serotonin reuptake inhibitor (e.g., duloxetine, sibutramine, venlafaxine, clomipramine, imipramine).[11]
Aquaculture
Methylene blue is used in aquaculture and by tropical fish hobbyists as a bacterial and fungal infection preventative on freshwater fish eggs. It is also commonly used as a additive in a solution in which infected (or newly purchased) fish are dipped (commonly called a dip). In the dip, the methylene blue serves to fight and kill the offending organisms, as well as increase the oxygen carrying capacity of the fish's hemoglobin. [12] While some hobbyists use methylene blue to treat fish infected with ich, the parasitic[protozoa]] Ichthyophthirius multifiliis, methylene blue has shown to not be the most effective solution, and other solutions, such as ionized copper, are instead suggested. [13] While methylene blue is non-toxic to fish if used in the proper dosage, it is toxic to live plants, and also will harm fish if placed in long-term contact with them.
Misuse
While methylene blue has many uses in the medicine, it has also been used inappropriately by pranksters, due to it's ability to alter urine with a green-blue color. About 75% of an oral dose of methylene blue is released into the urine (mostly in its reduced form - leucomethylene blue), thereby adding a blue-green hue to the urine (some of the remaining methylene blue is excreted via the bile). However, use of this substance in such a way is dangerous, because methylene blue is a biologically active substance[14], and if administered inappropriately, can lead to a number of health complications, including gastrointestinal disturbances and dysuria. Large doses of methylene blue can can produce methaemoglobinaemia, as well as chest pain, dyspnoea, restlessness, apprehension, tremors, a sense of oppression, urinary tract irritation, as well as a mild haemolysis with moderate hyperbilirubinaemia, reticulosis and slight anaemia.[15]
See also
- Prussian blue
- Gentian violet
Notes
- ↑ http://www.americanchemistry.com/s_chlorine/sec_content.asp?CID=1251&DID=4729&CTYPEID=113
- ↑ http://www.cci.ethz.ch/experiments/methylen/en/stat.html
- ↑ http://www.starch.dk/isi/methods/27DE.htm
- ↑ http://www.americanchemistry.com/s_chlorine/sec_content.asp?CID=1252&DID=4730&CTYPEID=113
- ↑ http://www.eng.umd.edu/~nsw/ench485/lab9b.htm
- ↑ http://wheat.pw.usda.gov/~lazo/methods/iubio/northgel.html
- ↑ http://www.bioscience-explained.org/EN1.2/schollar.html
- ↑ http://www.wfcc.info/tis/info2.html
- ↑ Schirmer H, Coulibaly B, Stich A, et al. (2003). Methylene blue as an antimalarial agent—past and future. Redox Rep. 8: 272–76.
- ↑ Meissner PE, Mandi G, Coulibaly B, et al. (2006). Methylene blue for malaria in Africa: results from a dose-finding study in combination with chloroquine. Malaria Journal 5: 84.
- ↑ Gillman PK. (2006). Methylene Blue implicated in potentially fatal serotonin toxicity. Anaesthesia 61: 1013-14.
- ↑ http://www.aquaria.info/index.php?name=PNphpBB2&file=viewtopic&p=344037
- ↑ http://www.wetwebmedia.com/methblueart.htm
- ↑ http://www.madsci.org/posts/archives/may99/925860441.Me.r.html
- ↑ http://www.medsafe.govt.nz/profs/datasheet/m/MethyleneBlueinj.htm
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