Gallic acid

Last updated
Gallic acid
Gallic acid.svg
Gallic acid molecule spacefill from xtal.png
Names
Preferred IUPAC name
3,4,5-Trihydroxybenzoic acid
Other names
Gallic acid
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.005.228 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 205-749-9
KEGG
PubChem CID
RTECS number
  • LW7525000
UNII
  • InChI=1S/C7H6O5/c8-4-1-3(7(11)12)2-5(9)6(4)10/h1-2,8-10H,(H,11,12) Yes check.svgY
    Key: LNTHITQWFMADLM-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C7H6O5/c8-4-1-3(7(11)12)2-5(9)6(4)10/h1-2,8-10H,(H,11,12)
    Key: LNTHITQWFMADLM-UHFFFAOYAN
  • O=C(O)c1cc(O)c(O)c(O)c1
Properties
C7H6O5
Molar mass 170.12 g/mol
AppearanceWhite, yellowish-white, or
pale fawn-colored crystals.
Density 1.694 g/cm3 (anhydrous)
Melting point 260 °C (500 °F; 533 K)
1.19 g/100 mL, 20°C (anhydrous)
1.5 g/100 mL, 20 °C (monohydrate)
Solubility soluble in alcohol, ether, glycerol, acetone
negligible in benzene, chloroform, petroleum ether
log P 0.70
Acidity (pKa)COOH: 4.5, OH: 10.
-90.0·10−6 cm3/mol
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Irritant
NFPA 704 (fire diamond)
NFPA 704.svgHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 0: Will not burn. E.g. waterInstability (yellow): no hazard codeSpecial hazards (white): no code
1
0
Lethal dose or concentration (LD, LC):
5000 mg/kg (rabbit, oral)
Safety data sheet (SDS) External MSDS
Related compounds
Related
phenols,
carboxylic acids
Related compounds
 Benzoic acid, Phenol, Pyrogallol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Gallic acid (also known as 3,4,5-trihydroxybenzoic acid) is a trihydroxybenzoic acid with the formula C 6 H 2(OH)3CO2H. It is classified as a phenolic acid. It is found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants. [1] It is a white solid, although samples are typically brown owing to partial oxidation. Salts and esters of gallic acid are termed "gallates".

Contents

Its name is derived from oak galls, which were historically used to prepare tannic acid. Despite the name, gallic acid does not contain gallium.

Isolation and derivatives

Electrostatic potential map of surface of gallic acid molecule Gallic acid ESP.png
Electrostatic potential map of surface of gallic acid molecule
Ellagic acid molecule structure resembles that of two gallic acid molecules assembled in head to tail position and linked together by a C-C bond (as in biphenyl) and two cyclic ester links (lactones) forming two additional 6-piece cycles. Ellagic acid.svg
Ellagic acid molecule structure resembles that of two gallic acid molecules assembled in head to tail position and linked together by a C–C bond (as in biphenyl) and two cyclic ester links (lactones) forming two additional 6-piece cycles.

Gallic acid is easily freed from gallotannins by acidic or alkaline hydrolysis. When heated with concentrated sulfuric acid, gallic acid converts to rufigallol. Hydrolyzable tannins break down on hydrolysis to give gallic acid and glucose or ellagic acid and glucose, known as gallotannins and ellagitannins, respectively. [2]

Biosynthesis

Chemical structure of 3,5-didehydroshikimate 3,5-didehydroshikimate.PNG
Chemical structure of 3,5-didehydroshikimate

Gallic acid is formed from 3-dehydroshikimate by the action of the enzyme shikimate dehydrogenase to produce 3,5-didehydroshikimate. This latter compound aromatizes. [3] [4]

Reactions

Oxidation and oxidative coupling

Alkaline solutions of gallic acid are readily oxidized by air. The oxidation is catalyzed by the enzyme gallate dioxygenase, an enzyme found in Pseudomonas putida .

Oxidative coupling of gallic acid with arsenic acid, permanganate, persulfate, or iodine yields ellagic acid, as does reaction of methyl gallate with iron(III) chloride. [5] Gallic acid forms intermolecular esters (depsides) such as digallic and cyclic ether-esters (depsidones). [5]

Hydrogenation

Hydrogenation of gallic acid gives the cyclohexane derivative hexahydrogallic acid. [6]

Decarboxylation

Heating gallic acid gives pyrogallol (1,2,3-trihydroxybenzene). This conversion is catalyzed by gallate decarboxylase.

Esterification

Many esters of gallic acid are known, both synthetic and natural. Gallate 1-beta-glucosyltransferase catalyzes the glycosylation (attachment of glucose) of gallic acid.

Historical context and uses

Gallic acid is an important component of iron gall ink, the standard European writing and drawing ink from the 12th to 19th centuries, with a history extending to the Roman empire and the Dead Sea Scrolls. Pliny the Elder (23-79 AD) describes the use of gallic acid as a means of detecting an adulteration of verdigris [7] and writes that it was used to produce dyes. Galls (also known as oak apples) from oak trees were crushed and mixed with water, producing tannic acid. It could then be mixed with green vitriol (ferrous sulfate) — obtained by allowing sulfate-saturated water from a spring or mine drainage to evaporate[ citation needed ] — and gum arabic from acacia trees; this combination of ingredients produced the ink. [8]

Gallic acid was one of the substances used by Angelo Mai (1782–1854), 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 rendering manuscripts too damaged for subsequent study by other researchers. [9]

Gallic acid was first studied by the Swedish chemist Carl Wilhelm Scheele in 1786. [10] In 1818, French chemist and pharmacist Henri Braconnot (1780–1855) devised a simpler method of purifying gallic acid from galls; [11] gallic acid was also studied by the French chemist Théophile-Jules Pelouze (1807–1867), [12] among others.

When mixed with acetic acid, gallic acid had uses in early types of photography, like the calotype to make the silver more sensitive to light; it was also used in developing photographs. [13]

Occurrence

Gallic acid is found in a number of land plants, such as the parasitic plant Cynomorium coccineum , [14] the aquatic plant Myriophyllum spicatum , and the blue-green alga Microcystis aeruginosa . [15] Gallic acid is also found in various oak species, [16] Caesalpinia mimosoides, [17] and in the stem bark of Boswellia dalzielii, [18] among others. Many foodstuffs contain various amounts of gallic acid, especially fruits (including strawberries, grapes, bananas), [19] [20] as well as teas, [19] [21] cloves, [22] and vinegars. [23] [ clarification needed ] Carob fruit is a rich source of gallic acid (24–165 mg per 100 g). [24]

Esters

Also known as galloylated esters:

Gallate esters are antioxidants useful in food preservation, with propyl gallate being the most commonly used. Their use in human health is scantly supported by evidence.

Spectral data

UV-Vis
Lambda-max:220, 271 nm (ethanol)
Spectrum of gallic acid Gallic acid spectrum.PNG
Spectrum of gallic acid
Extinction coefficient (log ε)
IR
Major absorption bandsν : 3491, 3377, 1703, 1617, 1539, 1453, 1254 cm−1 (KBr)
NMR
Proton NMR


(acetone-d6):
d : doublet, dd : doublet of doublets,
m : multiplet, s : singlet

 δ  :

7.15 (2H, s, H-3 and H-7)

Carbon-13 NMR


(acetone-d6):

δ  :

167.39 (C-1),
144.94 (C-4 and C-6),
137.77 (C-5),
120.81 (C-2),
109.14 (C-3 and C-7)

Other NMR data
MS
Masses of
main fragments		ESI-MS [M-H]- m/z : 169.0137 ms/ms (iontrap)@35 CE m/z product 125(100), 81(<1)

[17]

See also

Related Research Articles

<span class="mw-page-title-main">Tannin</span> Class of astringent, bitter plant polyphenolic chemical compounds

Tannins are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids.

<span class="mw-page-title-main">Flavan-3-ol</span> Category of polyphenol compound

Flavan-3-ols are a subgroup of flavonoids. They are derivatives of flavans that possess a 2-phenyl-3,4-dihydro-2H-chromen-3-ol skeleton. Flavan-3-ols are structurally diverse and include a range of compounds, such as catechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate, proanthocyanidins, theaflavins, thearubigins. They play a part in plant defense and are present in the majority of plants.

<span class="mw-page-title-main">Polyphenol</span> Class of chemical compounds

Polyphenols are a large family of naturally occurring phenols. They are abundant in plants and structurally diverse. Polyphenols include flavonoids, tannic acid, and ellagitannin, some of which have been used historically as dyes and for tanning garments.

<span class="mw-page-title-main">Iron gall ink</span> Ink made from iron salts and tannic acids from vegetable sources

Iron gall ink is a purple-black or brown-black ink made from iron salts and tannic acids from vegetable sources. It was the standard ink formulation used in Europe for the 1400-year period between the 5th and 19th centuries, remained in widespread use well into the 20th century, and is still sold today.

<span class="mw-page-title-main">Pyrogallol</span> Benzene-1,2,3-triol

Pyrogallol is an organic compound with the formula C6H3(OH)3. It is a water-soluble, white solid although samples are typically brownish because of its sensitivity toward oxygen. It is one of three isomers of benzenetriols.

<span class="mw-page-title-main">Ellagic acid</span> Natural phenol antioxidant

Ellagic acid is a polyphenol found in numerous fruits and vegetables. It is the dilactone of hexahydroxydiphenic acid.

<span class="mw-page-title-main">Propyl gallate</span> Chemical compound

Propyl gallate, or propyl 3,4,5-trihydroxybenzoate is an ester formed by the condensation of gallic acid and propanol. Since 1948, this antioxidant has been added to foods containing oils and fats to prevent oxidation. As a food additive, it is used under the E number E310.

<span class="mw-page-title-main">Epigallocatechin gallate</span> Catechin (polyphenol) in tea

Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is the ester of epigallocatechin and gallic acid, and is a type of catechin.

<span class="mw-page-title-main">Theaflavin digallate</span> Chemical compound

Theaflavin digallate (TFDG) is an antioxidant natural phenol found in black tea, and a theaflavin derivative.

The enzyme tannase (EC 3.1.1.20) catalyzes the following reaction:

<span class="mw-page-title-main">Phenolic content in wine</span> Wine chemistry

The phenolic content in wine refers to the phenolic compounds—natural phenol and polyphenols—in wine, which include a large group of several hundred chemical compounds that affect the taste, color and mouthfeel of wine. These compounds include phenolic acids, stilbenoids, flavonols, dihydroflavonols, anthocyanins, flavanol monomers (catechins) and flavanol polymers (proanthocyanidins). This large group of natural phenols can be broadly separated into two categories, flavonoids and non-flavonoids. Flavonoids include the anthocyanins and tannins which contribute to the color and mouthfeel of the wine. The non-flavonoids include the stilbenoids such as resveratrol and phenolic acids such as benzoic, caffeic and cinnamic acids.

<span class="mw-page-title-main">Ethyl gallate</span> Chemical compound

Ethyl gallate is a food additive with E number E313. It is the ethyl ester of gallic acid. Ethyl gallate is added to food as an antioxidant.

A gallotannin is any of a class of molecules belonging to the hydrolysable tannins. Gallotannins are polymers formed when gallic acid, a polyphenol monomer, esterifies and binds with the hydroxyl group of a polyol carbohydrate such as glucose.

A hydrolysable tannin or pyrogallol-type tannin is a type of tannin that, on heating with hydrochloric or sulfuric acids, yields gallic or ellagic acids.

The ellagitannins are a diverse class of hydrolyzable tannins, a type of polyphenol formed primarily from the oxidative linkage of galloyl groups in 1,2,3,4,6-pentagalloyl glucose. Ellagitannins differ from gallotannins, in that their galloyl groups are linked through C-C bonds, whereas the galloyl groups in gallotannins are linked by depside bonds.

<span class="mw-page-title-main">Gallocatechin gallate</span> Chemical compound

Gallocatechin gallate (GCG) is the ester of gallocatechin and gallic acid and a type of catechin. It is an epimer of epigallocatechin gallate (EGCG).

<span class="mw-page-title-main">Glucogallin</span> Chemical compound

Glucogallin is chemical compound formed from gallic acid and β-D-glucose. It can be found in oaks species like the North American white oak, European red oak and Amla fruit.

<i>Quercus infectoria</i> Species of oak tree

Quercus infectoria or the Aleppo oak is a species of oak well known for producing galls that have been traditionally used for centuries in Asia medicinally while also used in softening leather and in making black dye and ink.

<span class="mw-page-title-main">Phenolic content in tea</span> Natural plant compounds

The phenolic content in tea refers to the phenols and polyphenols, natural plant compounds which are found in tea. These chemical compounds affect the flavor and mouthfeel of tea. Polyphenols in tea include catechins, theaflavins, tannins, and flavonoids.

References

  1. ↑ Haslam, E.; Cai, Y. (1994). "Plant polyphenols (vegetable tannins): Gallic acid metabolism". Natural Product Reports. 11 (1): 41–66. doi:10.1039/NP9941100041. PMID   15206456.
  2. ↑ Andrew Pengelly (2004), The Constituents of Medicinal Plants (2nd ed.), Allen & Unwin, pp. 29–30
  3. ↑ Gallic acid pathway on metacyc.org
  4. ↑ Dewick, PM; Haslam, E (1969). "Phenol Biosynthesis in Higher Plants. Gallic Acid". Biochemical Journal. 113 (3): 537–542. doi:10.1042/bj1130537. PMC   1184696 . PMID   5807212.
  5. 1 2 Edwin Ritzer; Rudolf Sundermann (2007), "Hydroxycarboxylic Acids, Aromatic", Ullmann's Encyclopedia of Industrial Chemistry (7th ed.), Wiley, p. 6
  6. ↑ Albert W. Burgstahler and Zoe J. Bithos (1962). "Hexahydrogallic Acid and Hexahydrogallic Acid Triacetate". Organic Syntheses. 42: 62. doi:10.15227/orgsyn.042.0062.
  7. ↑ Pliny the Elder with John Bostock and H.T. Riley, trans., The Natural History of Pliny (London, England: Henry G. Bohn, 1857), vol. 6, p. 196. In Book 34, Chapter 26 of his Natural History, Pliny states that verdigris (a form of copper acetate (Cu(CH3COO)2·2Cu(OH)2), which was used to process leather, was sometimes adulterated with copperas (a form of iron(II) sulfate (FeSO4·7H2O)). He presented a simple test for determining the purity of verdigris. From p. 196: "The adulteration [of verdigris], however, which is most difficult to detect, is made with copperas; … The fraud may also be detected by using a leaf of papyrus, which has been steeped in an infusion of nut-galls; for it becomes black immediately upon the genuine verdigris being applied."
  8. ↑ Fruen, Lois. "Iron Gall Ink". Archived from the original on 2011-10-02.
  9. ↑ L.D. Reynolds and N.G. Wilson, "Scribes and Scholars" 3rd Ed. Oxford: 1991, pp 193–4.
  10. ↑ Carl Wilhelm Scheele (1786) "Om Sal essentiale Gallarum eller Gallåple-salt" (On the essential salt of galls or gall-salt), Kongliga Vetenskaps Academiens nya Handlingar (Proceedings of the Royal [Swedish] Academy of Science), 7: 30–34.
  11. ↑ Braconnot Henri (1818). "Observations sur la préparation et la purification de l'acide gallique, et sur l'existence d'un acide nouveau dans la noix de galle" [Observations on the preparation and purification of gallic acid, and on the existence of a new acid in galls]. Annales de Chimie et de Physique. 9: 181–184.
  12. ↑ J. Pelouze (1833) "Mémoire sur le tannin et les acides gallique, pyrogallique, ellagique et métagallique," Annales de chimie et de physique, 54: 337–365 [presented February 17, 1834].
  13. ↑ Taylor, Roger; Schaaf, Larry John (2007). Impressed by Light: British Photographs from Paper Negatives, 1840-1860. Metropolitan Museum of Art. ISBN   978-1-58839-225-1.
  14. ↑ Zucca, Paolo; Rosa, Antonella; Tuberoso, Carlo; Piras, Alessandra; Rinaldi, Andrea; Sanjust, Enrico; Dessì, Maria; Rescigno, Antonio (11 January 2013). "Evaluation of Antioxidant Potential of "Maltese Mushroom" (Cynomorium coccineum) by Means of Multiple Chemical and Biological Assays". Nutrients. 5 (1): 149–161. doi: 10.3390/nu5010149 . PMC   3571642 . PMID   23344249.
  15. ↑ Nakai, S (2000). "Myriophyllum spicatum-released allelopathic polyphenols inhibiting growth of blue-green algae Microcystis aeruginosa". Water Research. 34 (11): 3026–3032. Bibcode:2000WatRe..34.3026N. doi:10.1016/S0043-1354(00)00039-7.
  16. ↑ Mämmelä, Pirjo; Savolainen, Heikki; Lindroos, Lasse; Kangas, Juhani; Vartiainen, Terttu (2000). "Analysis of oak tannins by liquid chromatography-electrospray ionisation mass spectrometry". Journal of Chromatography A. 891 (1): 75–83. doi:10.1016/S0021-9673(00)00624-5. PMID   10999626.
  17. 1 2 Chanwitheesuk, Anchana; Teerawutgulrag, Aphiwat; Kilburn, Jeremy D.; Rakariyatham, Nuansri (2007). "Antimicrobial gallic acid from Caesalpinia mimosoides Lamk". Food Chemistry. 100 (3): 1044–1048. doi:10.1016/j.foodchem.2005.11.008.
  18. ↑ Alemika, Taiwo E.; Onawunmi, Grace O.; Olugbade, Tiwalade A. (2007). "Antibacterial phenolics from Boswellia dalzielii". Nigerian Journal of Natural Products and Medicine. 10 (1): 108–10.
  19. 1 2 Pandurangan AK, Mohebali N, Norhaizan ME, Looi CY (2015). "Gallic acid attenuates dextran sulfate sodium-induced experimental colitis in BALB/c mice". Drug Design, Development and Therapy. 9: 3923–34. doi: 10.2147/DDDT.S86345 . PMC   4524530 . PMID   26251571.
  20. ↑ Koyama, K; Goto-Yamamoto, N; Hashizume, K (2007). "Influence of maceration temperature in red wine vinification on extraction of phenolics from berry skins and seeds of grape (Vitis vinifera)". Bioscience, Biotechnology, and Biochemistry. 71 (4): 958–65. doi: 10.1271/bbb.60628 . PMID   17420579.
  21. ↑ Hodgson JM, Morton LW, Puddey IB, Beilin LJ, Croft KD (2000). "Gallic acid metabolites are markers of black tea intake in humans". Journal of Agricultural and Food Chemistry. 48 (6): 2276–80. doi:10.1021/jf000089s. PMID   10888536.
  22. ↑ Pathak, S. B.; Niranjan, K.; Padh, H.; Rajani, M.; et al. (2004). "TLC Densitometric Method for the Quantification of Eugenol and Gallic Acid in Clove". Chromatographia. 60 (3–4): 241–244. doi:10.1365/s10337-004-0373-y. S2CID   95396304.
  23. ↑ Gálvez, Miguel Carrero; Barroso, Carmelo García; Pérez-Bustamante, Juan Antonio (1994). "Analysis of polyphenolic compounds of different vinegar samples". Zeitschrift für Lebensmittel-Untersuchung und -Forschung. 199: 29–31. doi:10.1007/BF01192948. S2CID   91784893.
  24. ↑ Goulas, Vlasios; Stylos, Evgenios; Chatziathanasiadou, Maria; Mavromoustakos, Thomas; Tzakos, Andreas (10 November 2016). "Functional Components of Carob Fruit: Linking the Chemical and Biological Space". International Journal of Molecular Sciences. 17 (11): 1875. doi: 10.3390/ijms17111875 . ISSN   1422-0067. PMC   5133875 . PMID   27834921.
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