Gallic acid
Encyclopedia
Gallic acid is a trihydroxybenzoic acid
, a type of phenolic acid, a type of organic acid, also known as 3,4,5-trihydroxybenzoic acid
, found in gallnuts, sumac
, witch hazel
, tea
leaves, oak
bark
, and other plant
s. The chemical formula is C
6H
2(OH
)3COOH. Gallic acid is found both free and as part of tannin
s. Salts and ester
s of gallic acid are termed 'gallates'. Despite its name, it does not contain gallium
.
Gallic acid is commonly used in the pharmaceutical industry. 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. Gallic acid can also be used as a starting material in the synthesis of the psychedelic alkaloid mescaline
.
Gallic acid seems to have anti-fungal and anti-viral properties. Gallic acid acts as an antioxidant and helps to protect human 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 ointments to treat psoriasis and external haemorrhoids contain gallic acid.
from acacia trees to produce the ink .
Gallic acid was one of the substances used by Angelo Mai
(1782–1854) among other early investigators of palimpsest
s 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.
It has been discovered by French chemist and pharmacist Henri Braconnot
(1780–1855) in 1818 and studied by French chemist Théophile-Jules Pelouze
(1807–1867).
Early photographers also used it, Joseph Bancroft Reade
(1801–1870) for instance and William Fox Talbot
(1800–1877) for developing latent images in calotype
s. It has also been used as a coating agent in zincography
.
It was also used by George Washington
to communicate with spies during the United States war of Independence (American Revolution
) according to the miniseries America: The Story of Us
.
Gallic acid is a component of some whistle mix
tures.
Reference
(EC 2.4.1.136) is an enzyme that uses UDP-glucose and gallate, whereas its two products are UDP and 1-galloyl-beta-D-glucose.
Gallate decarboxylase
(EC 4.1.1.59)is another enzyme.
Trihydroxybenzoic acid
Trihydroxybenzoic acid may refer to the following phenolic acids :* Gallic acid * Phloroglucinol carboxylic acid O-methylated trihydroxybenzoic acids are :* Eudesmic acid* Syringic acid...
, a type of phenolic acid, a type of organic acid, also known as 3,4,5-trihydroxybenzoic acid
Benzoic acid
Benzoic acid , C7H6O2 , is a colorless crystalline solid and the simplest aromatic carboxylic acid. The name derived from gum benzoin, which was for a long time the only source for benzoic acid. Its salts are used as a food preservative and benzoic acid is an important precursor for the synthesis...
, found in gallnuts, sumac
Sumac
Sumac is any one of approximately 250 species of flowering plants in the genus Rhus and related genera, in the family Anacardiaceae. Sumacs grow in subtropical and temperate regions throughout the world, especially in Africa and North America....
, witch hazel
Witch hazel
Witch hazel may refer to:*Witch-hazel , a genus of decorative shrubs in North America and east Asia*Witch hazel , an astringent topical medicine derived from the Hamamelis plant...
, tea
Tea
Tea is an aromatic beverage prepared by adding cured leaves of the Camellia sinensis plant to hot water. The term also refers to the plant itself. After water, tea is the most widely consumed beverage in the world...
leaves, oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
bark
Bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...
, and other plant
Plant
Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...
s. The chemical formula is C
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
6H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
2(OH
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
)3COOH. Gallic acid is found both free and as part of tannin
Tannin
A tannin is an astringent, bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids.The term tannin refers to the use of...
s. Salts and ester
Ester
Esters are chemical compounds derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH group is replaced by an -O-alkyl group, and most commonly from carboxylic acids and...
s of gallic acid are termed 'gallates'. Despite its name, it does not contain gallium
Gallium
Gallium is a chemical element that has the symbol Ga and atomic number 31. Elemental gallium does not occur in nature, but as the gallium salt in trace amounts in bauxite and zinc ores. A soft silvery metallic poor metal, elemental gallium is a brittle solid at low temperatures. As it liquefies...
.
Gallic acid is commonly used in the pharmaceutical industry. It is used as a standard
Standard solution
In analytical chemistry, a standard solution is a solution containing a precisely known concentration of an element or a substance i.e, a known weight of solute is dissolved to make a specific volume. It is prepared using a standard substance, such as a primary standard. Standard solutions are used...
for determining the phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...
content of various analytes by the Folin-Ciocalteau assay
Folin-Ciocalteu reagent
The Folin–Ciocalteu reagent or Folin's phenol reagent or Folin–Denis reagent, also called the Gallic Acid Equivalence method , is a mixture of phosphomolybdate and phosphotungstate used for the colorimetric assay of phenolic and polyphenolic antioxidants...
; results are reported in gallic acid equivalents. Gallic acid can also be used as a starting material in the synthesis of the psychedelic alkaloid mescaline
Mescaline
Mescaline or 3,4,5-trimethoxyphenethylamine is a naturally occurring psychedelic alkaloid of the phenethylamine class used mainly as an entheogen....
.
Gallic acid seems to have anti-fungal and anti-viral properties. Gallic acid acts as an antioxidant and helps to protect human 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 ointments to treat psoriasis and external haemorrhoids contain 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 century with a history extending to the Roman empire and the dead sea scrolls. Pliny the Elder (23-79 AD) describes his experiments with it 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 gallic acid (hence the name). It could then be mixed with green vitriol (ferrous sulfate), obtained by allowing sulfate saturated spring or mine drainage water to evaporate, and gum arabicGum arabic
220px|thumb|right|Acacia gumGum arabic, also known as acacia gum, chaar gund, char goond, or meska, is a natural gum made of hardened sap taken from two species of the acacia tree; Acacia senegal and Acacia seyal...
from acacia trees to produce the ink .
Gallic acid was one of the substances used by Angelo Mai
Angelo Mai
Angelo Mai was an Italian Cardinal and philologist. He won a European reputation for publishing for the first time a series of previously unknown ancient texts. These he was able to discover and publish, first while in charge of the Biblioteca Ambrosiana in Milan and then in the same role at the...
(1782–1854) among other early investigators of palimpsest
Palimpsest
A palimpsest is a manuscript page from a scroll or book from which the text has been scraped off and which can be used again. The word "palimpsest" comes through Latin palimpsēstus from Ancient Greek παλίμψηστος originally compounded from πάλιν and ψάω literally meaning “scraped...
s 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.
It has been discovered by French chemist and pharmacist Henri Braconnot
Henri Braconnot
Henri Braconnot was a French chemist and pharmacist.He was born in Commercy, his father being a counsel at the local parliament...
(1780–1855) in 1818 and studied by French chemist Théophile-Jules Pelouze
Théophile-Jules Pelouze
Théophile-Jules Pelouze was a French chemist. He was born at Valognes, and died in Paris....
(1807–1867).
Early photographers also used it, Joseph Bancroft Reade
Joseph Bancroft Reade
Rev. Joseph Bancroft Reade FRS was an English clergyman, amateur scientist and pioneer of photography.-Early life:...
(1801–1870) for instance and William Fox Talbot
William Fox Talbot
William Henry Fox Talbot was a British inventor and a pioneer of photography. He was the inventor of calotype process, the precursor to most photographic processes of the 19th and 20th centuries. He was also a noted photographer who made major contributions to the development of photography as an...
(1800–1877) for developing latent images in calotype
Calotype
Calotype or talbotype is an early photographic process introduced in 1841 by William Henry Fox Talbot, using paper coated with silver iodide. The term calotype comes from the Greek for 'beautiful', and for 'impression'....
s. It has also been used as a coating agent in zincography
Zincography
Zincography was a planographic printing process that used zinc plates. Alois Senefelder first mentioned zinc's lithographic use as a substitute for Bavarian limestone in his 1801 English patent specifications . In 1834, the Frenchman Breugnot patented a zincographic printing process, producing...
.
It was also used by George Washington
George Washington
George Washington was the dominant military and political leader of the new United States of America from 1775 to 1799. He led the American victory over Great Britain in the American Revolutionary War as commander-in-chief of the Continental Army from 1775 to 1783, and presided over the writing of...
to communicate with spies during the United States war of Independence (American Revolution
American Revolution
The American Revolution was the political upheaval during the last half of the 18th century in which thirteen colonies in North America joined together to break free from the British Empire, combining to become the United States of America...
) according to the miniseries America: The Story of Us
America: The Story of Us
America: The Story of Us is a six-part, 12-hour documentary television miniseries that premiered on April 25, 2010, on History...
.
Gallic acid is a component of some whistle mix
Whistle mix
Whistle mix is a general term to refer to any pyrotechnic composition that emits a whistling sound when pressed into a tube and ignited. It is used as a rocket propellant, particularly in small bottle rockets...
tures.
List of plants or foods that contain the chemical
- Areca nut
- BearberryBearberryBearberries are three species of dwarf shrubs in the genus Arctostaphylos. Unlike the other species of Arctostaphylos , they are adapted to Arctic and sub-Arctic climates, and have a circumpolar distribution in northern North America, Asia and Europe, one with a small highly disjunctive population...
(Arctostaphylos sp) - BergeniaBergeniaBergenia is a genus of ten species of flowering plants in the family Saxifragaceae, native to central Asia, from Afghanistan to China and the Himalayan region...
sp - BlackberryBlackberryThe blackberry is an edible fruit produced by any of several species in the Rubus genus of the Rosaceae family. The fruit is not a true berry; botanically it is termed an aggregate fruit, composed of small drupelets. The plants typically have biennial canes and perennial roots. Blackberries and...
- Caesalpinia mimosoidesCaesalpinia mimosoidesCaesalpinia mimosoides is a plant species in the genus Caesalpinia.Gallic acid can be extracted from the plant. It is a food plant for the caterpillars of Eurema blanda....
- Hot chocolateHot chocolateHot chocolate is a heated beverage typically consisting of shaved chocolate, melted chocolate or cocoa powder, heated milk or water, and sugar...
- Drosera (sundew)
- Juglans regia (Common walnut)
- MangoMangoThe mango is a fleshy stone fruit belonging to the genus Mangifera, consisting of numerous tropical fruiting trees in the flowering plant family Anacardiaceae. The mango is native to India from where it spread all over the world. It is also the most cultivated fruit of the tropical world. While...
in peels and leaves - Phyllanthus emblica (Indian gooseberry) in fruits
- RaspberryRaspberryThe raspberry or hindberry is the edible fruit of a multitude of plant species in the genus Rubus, most of which are in the subgenus Idaeobatus; the name also applies to these plants themselves...
- Syzygium aromaticum (clove)
- Rhodiola roseaRhodiola roseaRhodiola rosea is a plant in the Crassulaceae family that grows in cold regions of the world. These include much of the Arctic, the mountains of Central Asia, the Rocky Mountains, and mountainous parts of Europe, such as the Alps, Pyrenees, Carpathian Mountains, Scandinavia, Iceland, Great...
(Golden root) - TriphalaTriphalaTriphala is an Ayurvedic herbal rasayana formula consisting of equal parts of three myrobalans, taken without seed: Amalaki , Bibhitaki , and Haritaki...
(Ayurvedic herbal rasayana formula) - Witch hazelWitch Hazel (astringent)Witch hazel is an astringent produced from the leaves and bark of the North American Witch-hazel shrub , which grows naturally from Nova Scotia west to Ontario, Canada, and south to Florida and Texas in the United States...
(Hamamelis virginiana) - White teaWhite teaWhite tea is a lightly oxidized tea grown and harvested almost exclusively in China, primarily in the Fujian province.White tea comes from the delicate buds and younger leaves of the Chinese Camellia sinensis plant. These buds and leaves are allowed to wither in natural sunlight before they are...
- Toona sinensisToona sinensisToona sinensis Toona sinensis Toona sinensis (syn. Cedrela sinensis A.Juss.; Chinese Mahogany, Chinese Toon, or Red Toon is a species of Toona native to eastern and southeastern Asia, from North Korea south through most of eastern, central and southwestern China to Nepal, northeastern India,...
Spectral data
| UV-Vis | |
|---|---|
| Retention time | |
| Lambda-max: | 220, 271 nm Nanometre A nanometre is a unit of length in the metric system, equal to one billionth of a metre. The name combines the SI prefix nano- with the parent unit name metre .The nanometre is often used to express dimensions on the atomic scale: the diameter... (ethanol) |
| Extinction coefficient Molar absorptivity The molar absorption coefficient, molar extinction coefficient, or molar absorptivity, is a measurement of how strongly a chemical species absorbs light at a given wavelength... (log ε) |
|
| IR Infrared Infrared light is electromagnetic radiation with a wavelength longer than that of visible light, measured from the nominal edge of visible red light at 0.74 micrometres , and extending conventionally to 300 µm... |
|
| Major absorption bands | ν : 3491, 3377, 1703, 1617, 1539, 1453, 1254 cm−1 (KBr) |
| NMR NMR spectroscopy Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy, is a research technique that exploits the magnetic properties of certain atomic nuclei to determine physical and chemical properties of atoms or the molecules in which they are contained... |
|
| Proton NMR Proton NMR Proton NMR is the application of nuclear magnetic resonance in NMR spectroscopy with respect to hydrogen-1 nuclei within the molecules of a substance, in order to determine the structure of its molecules. In samples where natural hydrogen is used, practically all of the hydrogen consists of the... (acetone-d6): d : doublet, dd : doublet of doublets, m : multiplet, s : singlet |
δ Chemical shift In nuclear magnetic resonance spectroscopy, the chemical shift is the resonant frequency of a nucleus relative to a standard. Often the position and number of chemical shifts are diagnostic of the structure of a molecule... : 7.15 (2H, s, H-3 and H-7) |
| Carbon-13 NMR Carbon-13 NMR Carbon-13 NMR is the application of nuclear magnetic resonance spectroscopy to carbon. It is analogous to proton NMR and allows the identification of carbon atoms in an organic molecule just as proton NMR identifies hydrogen atoms... (acetone-d6): |
δ Chemical shift In nuclear magnetic resonance spectroscopy, the chemical shift is the resonant frequency of a nucleus relative to a standard. Often the position and number of chemical shifts are diagnostic of the structure of a molecule... : 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 Mass spectrometry Mass spectrometry is an analytical technique that measures the mass-to-charge ratio of charged particles.It is used for determining masses of particles, for determining the elemental composition of a sample or molecule, and for elucidating the chemical structures of molecules, such as peptides and... |
|
| Masses of main fragments |
ESI-MS [M-H]- m/z : 169.0137 |
Reference
Esters
Also known as galloylated esters:- Ethyl gallateEthyl gallateEthyl 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 food additive with E number E313 - Propyl gallatePropyl gallatePropyl 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.-Description:Propyl...
, or propyl 3,4,5-trihydroxybenzoate, an ester formed by the condensation of gallic acid and propanol - Octyl gallateOctyl gallateOctyl gallate is the ester of octanol and gallic acid. As a food additive it is used under the E number E311 as an antioxidant and preservative....
, the ester of octanol and gallic acid - Dodecyl gallateDodecyl gallateDodecyl gallate, or lauryl gallate, is the ester of dodecanol and gallic acid. As a food additive it is used under the E number E312 as an antioxidant and preservative....
, or lauryl gallate, the ester of dodecanol and gallic acid - Epicatechin gallateEpicatechin gallateEpicatechin gallate is a flavan-3-ol, a type of flavonoid, present in green tea. It is also reported in buckwheat and in grape....
, a flavan-3-ol, a type of flavonoid, present in green tea - Epigallocatechin gallateEpigallocatechin gallateEpigallocatechin gallate , also known as epigallocatechin 3-gallate, is the ester of epigallocatechin and gallic acid, and is a type of catechin....
(EGCG), also known as epigallocatechin 3-gallate, the ester of epigallocatechin and gallic acid, and a type of catechin - Gallocatechin gallateGallocatechin gallateGallocatechin gallate is the ester of gallocatechin and gallic acid and a type of catechin. It is an epimer of epigallocatechin gallate ....
(GCG), the ester of gallocatechin and gallic acid and a type of flavan-3ol - Theaflavin-3-gallateTheaflavin-3-gallateTheaflavin-3-gallate is a theaflavin derivative. It can be found in black tea....
, a theaflavin derivative
Metabolism
Gallate 1-beta-glucosyltransferaseGallate 1-beta-glucosyltransferase
In enzymology, a gallate 1-beta-glucosyltransferase is an enzyme that catalyzes the chemical reactionThus, the two substrates of this enzyme are UDP-glucose and gallate, whereas its two products are UDP and 1-galloyl-beta-D-glucose....
(EC 2.4.1.136) is an enzyme that uses UDP-glucose and gallate, whereas its two products are UDP and 1-galloyl-beta-D-glucose.
Gallate decarboxylase
Gallate decarboxylase
In enzymology, a gallate decarboxylase is an enzyme that catalyzes the chemical reactionHence, this enzyme has one substrate, 3,4,5-trihydroxybenzoate, and two products, pyrogallol and CO2....
(EC 4.1.1.59)is another enzyme.