A colorless crystalline compound, C7H6O5, derived from tannin and used as a tanning agent, as an ink dye, and in photography and the manufacture of paper.
[French acide gallique, from galle, plant gall. See gall3.]
gallic acid
Dictionary:
gal·lic acid (găl'ĭk, gô'lĭk)  |
n.
A colorless crystalline compound, C7H6O5, derived from tannin and used as a tanning agent, as an ink dye, and in photography and the manufacture of paper.
A colorless crystalline compound, C7H6O5, derived from tannin and used as a tanning agent, as an ink dye, and in photography and the manufacture of paper.
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| Chemistry Dictionary: gallic acid |
Variant: 3,4,5-trihydroxybenzoic acid
A colourless crystalline aromatic compound, C6H2(OH)3COOH; m.p. 253°C. It occurs in wood, oak galls, and tea, and is a component of tannins. It can be made from tannin by acid hydrolysis or fermentation. Gallic acid is used to make ink and various dyes. On heating it yields pyrogallol.
Gallic acid
| Dental Dictionary: gallic acid |
n
An astringent used topically, made from tannic acid or nut-galls, and chemically known as 3,4,5-trihydroxybenzoic acid.
| Columbia Encyclopedia: gallic acid |
gallic acid or (trī'hīdrŏk'sēbĕnzō'ĭk), C6H2(OH)3CO2H, colorless crystalline organic acid found in gallnuts, sumach, tea leaves, oak bark, and many other plants, both in its free state and as part of the tannin molecule (see tannin). Since gallic acid has hydroxyl groups and a carboxylic acid group in the same molecule, two molecules of it can react with one another to form an ester, digallic acid. Gallic acid is obtained by the hydrolysis of tannic acid with sulfuric acid. When heated above 220°C, gallic acid loses carbon dioxide to form pyrogallol, or 1,2,3-trihydroxybenzene, C6H3(OH)3, which is used in the production of azo dyes and photographic developers and in laboratories for absorbing oxygen.
| Wikipedia: Gallic acid |
| Gallic acid | |
|---|---|
 |
 |
| IUPAC name |
3,4,5-trihydroxybenzoic acid
|
| Other names | Gallic acid Gallate 3,4,5-trihydroxybenzoate |
| Identifiers | |
| CAS number | 149-91-7  ,[5995-86-8] (Monohydrate) |
| PubChem | 370 |
| SMILES |
Oc1cc(cc(O)c1O)C(O)=O
|
| Properties | |
| Molecular formula | C7H6O5 |
| Molar mass | 170.12 g/mol |
| Exact mass | 170.021523 |
| Appearance | White, yellowish-white, or pale fawn-colored crystals. |
| Density | 1.7 g/cm3 (anhydrous) |
| Melting point |
250 °C, 523 K, 482 °F |
| Solubility in water | 1.1 g/100 ml water @ 20° C (anhydrous) 1.5 g/100 ml water @ 20 °C (monohydrate) |
| Acidity (pKa) | COOH: 4.5, OH: 10. |
| Hazards | |
| MSDS | External MSDS |
| Main hazards | Irritant |
| Related compounds | |
| Related compounds | Benzoic acid, Phenol, Pyrogallol |
| (what is this?) (verify) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
|
| Infobox references | |
Gallic acid is an organic acid, also known as 3,4,5-trihydroxybenzoic acid, found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants.[1] The chemical formula is C6H2(OH)3COOH. Gallic acid is found both free and as part of tannins. Salts and esters of gallic acid are termed gallates. Despite its name, it does not contain gallium.
Gallic acid is commonly used in the pharmaceutical industry.[2] It is used as a standard for determining the phenol content of various analytes by the Folin-Ciocalteau assay; results are reported in gallic acid equivalents.[3] Gallic acid can also be used as a starting material in the synthesis of the psychedelic alkaloid mescaline.[4]
Gallic acid was one of the substances used by Angelo Mai among other early investigators of palimpsests to clear the top layer of text off and reveal hidden manuscripts underneath. Mai was the first to employ it, but did so "with a heavy hand," often damaging manuscripts for future study.[citation needed]
"Gallic acid seems to have anti-fungal and anti-viral properties. Gallic acid acts as a antioxidant and helps to protect our cells against oxidative damage. Gallic acid was found to show cytotoxicity against cancer cells, without harming healthy cells. Gallic acid is used as a remote astringent in cases of internal haemorrhage. Gallic acid is also used to treat albuminuria and diabetes. Some ointment to treat psoriasis and external haemorrhoids contain gallic acid."[5]
Contents |
List of plants that contain the chemical
See also
References
- ^ LD Reynolds and NG Wilson, “Scribes and Scholars” 3rd Ed. Oxford: 1991. pp193–4.
- ^ S. M. Fiuza. "Phenolic acid derivatives with potential anticancer properties––a structure–activity relationship study. Part 1: Methyl, propyl and octyl esters of caffeic and gallic acids". Elsevier. http://dx.doi.org/10.1016/j.bmc.2004.04.026.
- ^ Andrew Waterhouse. "Folin-Ciocalteau Micro Method for Total Phenol in Wine". UC Davis. http://waterhouse.ucdavis.edu/phenol/folinmicro.htm.
- ^ Tsao, Makepeasce (July 1951). "A New Synthesis Of Mescaline". Journal of the American Chemical Society 73 (11): 5495-5496. ISSN 0002-7863.
- ^ phytochemicals.info
- ^ Pathak, S. B. et al. (2004). "TLC Densitometric Method for the Quantification of Eugenol and Gallic Acid in Clove". Chromatographia 60 (3 - 4): 241 - 244. doi:.
External links
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Mentioned in
- witch hazel
- gallate
- tannase (biochemistry)
- ellagic
- rufigallic
- gallein
- gallates
- subgallate
- bablah
- divi-divi
- sinapic
- calotype (graphic arts)
- erigeron oil (materials)
- pyrogallol
