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Gallic acid is a trihydroxybenzoic acid, a type of phenolic acid, a type of organic acid, also known as 3,4,5- trihydroxy benzoic acid, found in gallnuts, sumac, witch hazel, tea leaves, oak bark, and other plants. The chemical formula is C6H2(OH)3COOH.
Gallic acid is found both free and as part of hydrolyzable tannins.
Gallic acid is commonly used in the pharmaceutical industry.
CAS Number: 149-91-7
Molecular Formula: C7H6O5
Molecular Weight: 170.12
EINECS Number: 205-749-9
Synonyms: Gallic acid, 3,4,5-Trihydroxybenzoic acid, 149-91-7, Benzoic acid, 3,4,5-trihydroxy-, Gallic acid, tech., Pyrogallol-5-carboxylic acid, Kyselina gallova, DTXSID0020650, NSC-20103, NSC-674319, CHEBI:30778, 632XD903SP, NSC20103, DTXCID60650, Acid, Gallic, Gallic Acid 1520, RefChem:6437, 3,4,5-hydroxybenzoic acid, 205-749-9, GALLIC ACID ANHYDROUS, MFCD00002510, GALOP, HSDB 2117, CCRIS 5523, NSC 674319, AI3-16412, Kyselina 3,4,5-trihydroxybenzoova, CHEMBL288114, 3,4,5-trihydroxy-Benzoic acid, NSC674319, NCGC00091125-01, 3,4,5-Trihydroxybenzoic acid, anhydrous, Kyselina gallova [Czech], CAS-149-91-7, Gallic acid [NF], SR-05000001537, EINECS 205-749-9, NSC 20103, BRN 2050274, gallic-acid, UNII-632XD903SP, Kyselina 3,4,5-trihydroxybenzoova [Czech], Gallic acid tech., Gallic Acid, F, GDE, Deuterated gallic acid, Spectrum_000342, Gallic acid (Standard), SpecPlus_000307, 5-Trihydroxybenzoic acid, Spectrum2_000399, Spectrum3_000254, Spectrum4_001544, Spectrum5_000108, GALLIC ACID [MI], bmse000389, 3,5-Trihydroxybenzoic acid, GALLIC ACID [HSDB], WLN: QVR CQ DQ EQ, 3,4,5-trihydroxy-Benzoate, Oprea1_087792, SCHEMBL15012, 3,4,5-Trihydroxybenzoicacid, BSPBio_001668, KBioGR_002008, KBioSS_000822, SPECTRUM210369, 3-10-00-02070 (Beilstein Handbook Reference), BIDD:ER0374, DivK1c_006403, GALLIC ACID [WHO-DD], SCHEMBL407763, SPBio_000617, 3,4,5-Trihydroxybenzoate, X, Benzoic acid,4,5-trihydroxy-, Gallic acid, 98% 250GR, GTPL5549, orb1310208, orb3025511, HY-N0523R, KBio1_001347, KBio2_000822, KBio2_003390, KBio2_005958, KBio3_001168, CPD-183, Gallic acid, puriss., 98.0%, MSK2307, GLXC-07618, HMS1923K07, HMS2091A07, HMS5083N19, HMS6019I06, Pharmakon1600-00210369, BB_NC-02799, HY-N0523, NSC36997, ULA66092, Tox21_111089, Tox21_202515, BBL009937, BDBM50085536, CCG-38670, EBC-12174, NSC-36997, NSC755825, s4603, SBB008781, STK298718, AKOS000119625, Tox21_111089_1, AC-1206, CS-8191, FG11942, NSC-755825, PS-8710, SDCCGMLS-0066503.P001, 3,4,5-Trihydroxybenzoic acid anhydrous, NCGC00091125-02, NCGC00091125-03, NCGC00091125-04, NCGC00091125-05, NCGC00091125-07, NCGC00091125-13, NCGC00091125-14, NCGC00260064-01, DA-33612, ST083487, SY038078, SBI-0052184.P002, Gallic acid, 97.5-102.5% (titration), G0011, NS00013682, EN300-21542, C01424, D85056, 3,4,5-trihydroxybenzoic acid (ACD/Name 4.0), AB00052697_03, F358297, Q375837, SR-05000001537-1, SR-05000001537-2, SR-05000001537-3, BRD-K77345217-001-01-9, BRD-K77345217-001-05-0, F1908-0156, Gallic acid, certified reference material, TraceCERT(R), Z104501122, 78563C7D-0E2D-4766-A8EA-670A03C78FCF, Dodecyl Gallate EP Impurity A; Octyl Gallate EP Impurity A; Gallic Acid, InChI=1/C7H6O5/c8-4-1-3(7(11)12)2-5(9)6(4)10/h1-2,8-10H,(H,11,12, 137657-43-3, 31387-49-2, Gallic acid, 98% 250GR;Gallic acid, 98% 5GR;Gallic acid 0;3,4,5-Trihydroxybenzoic acid, anhydrous 99%;Gallic acid, 5-Carboxybenzene-1,2,3-triol;BETZ 0276;GALLIC ACID;GALLIC ACID-1-HYDRATE
Gallic acid 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 antiviral 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.
Gallic acid is a naturally occurring organic acid belonging to the group of phenolic acids.
Its chemical name is 3,4,5-trihydroxybenzoic acid, reflecting the presence of three hydroxyl (–OH) groups attached to a benzoic acid core.
Gallic acid has the molecular formula C₇H₆O₅.
Gallic acid is widely found in plants and plant-derived materials.
It occurs naturally in gallnuts, oak bark, tea leaves, grapes, berries, and various fruits.
Gallic acid is also released during the hydrolysis of tannins, especially gallotannins.
Physically, gallic acid appears as a white to pale yellow crystalline solid.
It has a slightly astringent taste and is soluble in water, alcohol, and acetone.
Gallic acids solubility increases with temperature.
Chemically, gallic acid is known for its strong antioxidant properties.
The multiple hydroxyl groups allow it to donate hydrogen atoms and scavenge free radicals.
This makes it an important model compound in antioxidant research.
Gallic acid has been used historically in ink and dye production, particularly in iron gall ink.
It also plays a role in tanning and color chemistry due to its ability to form complexes with metal ions.
These metal-binding properties are still relevant in analytical chemistry.
In modern contexts, gallic acid is studied extensively in food science, pharmaceuticals, and biochemistry.
It is valued for its antioxidant, antimicrobial, and anti-inflammatory activities.
Gallic acid is also used as a reference compound in analytical and biological research.
Overall, gallic acid is an important plant-derived phenolic compound with broad scientific, industrial, and biological relevance.
Its simple structure combined with high reactivity makes it a key molecule in both traditional and modern applications.
Gallic acid, also known as trihydroxybenzoic acid, is a colorless crystalline needles or prisms that is obtained from nutgall tannins.
Gallic acid is soluble in hot water, ether, ethanol, acetone and glycerin, insoluble in cold water, insoluble in benzene and chloroform and has a melting point of 235 to 240 °C (decomposition).
When heated to 100-120°C, crystal water will be lost, and when heated above 200°C, carbon dioxide will be lost to generate pyrogallic acid (ie, pyrogallol).
Gallic acid is used in photography, tanning, ink manufacture and pharmaceuticals.
Gallic acid is considered a weak organic acid, with acidic behavior primarily due to its carboxyl group.
Its hydroxyl groups can also participate in hydrogen bonding and ionization under certain conditions.
This combination influences its solubility and reactivity in aqueous systems.
In polymer and materials chemistry, gallic acid is used as a functional monomer or crosslinking component.
Its multiple reactive sites allow it to bind to polymers or form coordination networks.
This property is explored in bio-based and sustainable material development.
Gallic acid participates in enzymatic and non-enzymatic browning reactions.
Under oxidative conditions, it can polymerize or form dark-colored complexes.
This behavior is relevant in food chemistry and natural product processing.
Molecular formula: C7H6O5
Molecular weight: 170.12 g/mol
Melting point: 251 °C (decomposition)
Boiling point: 259.73 °C (estimate)
Density: 1.694 g/cm3
Vapor pressure: 0 Pa (25 °C)
Refractive index: 1.5690 (estimate)
Storage temperature: 2–8 °C
Solubility: Slightly soluble in methanol; slightly soluble in water when heated
Water solubility: 12 g/L (cold water)
Form: Powder
Color: Off-white
pKa: 4.41 (25 °C)
pH (1 mM): 3.75
pH (10 mM): 3.22
pH (100 mM): 2.71
Biological source: Plant fruit
Merck index: 14,4345
BRN: 2050274
Stability: Stable; may discolor upon light exposure; hygroscopic; incompatible with strong oxidizing agents, strong bases, acid chlorides, acid anhydrides
Major application: Agriculture; metabolomics; microbiology; vitamins and nutraceuticals; natural products
Cosmetics ingredients functions: Antioxidant
InChI: 1S/C7H6O5/c8-4-1-3(7(11)12)2-5(9)6(4)10/h1-2,8-10H,(H,11,12)
InChIKey: LNTHITQWFMADLM-UHFFFAOYSA-N
SMILES: OC(=O)c1cc(O)c(O)c(O)c1
LogP: 0.7
Gallic acid plays a key role in plant defense mechanisms.
Gallic acid contributes to protection against pathogens, insects, and oxidative stress in plants.
Its presence in tannin-rich tissues is part of the plant’s natural protective chemistry.
In biochemical systems, gallic acid readily undergoes oxidation–reduction reactions.
Gallic acid can form quinone-like structures under oxidative conditions.
This reactivity underlies both its antioxidant behavior and its ability to interact with proteins and metals.
Gallic acid shows a strong tendency to chelate metal ions such as iron and copper.
These complexes can influence redox reactions and color formation.
This property explains its historical importance in iron gall inks and analytical chemistry.
In food science, gallic acid contributes to astringency and flavor characteristics.
It influences taste perception in teas, wines, and fruits.
Its concentration can affect sensory quality and perceived bitterness.
Gallic acid is often used as a reference standard in antioxidant assays.
Methods such as total phenolic content (expressed as gallic acid equivalents) rely on it.
This makes it a benchmark compound in food and natural product analysis.
In pharmaceutical and biomedical research, gallic acid is studied for biological activity at the cellular level.
It has been investigated for interactions with enzymes, membranes, and signaling pathways.
These studies focus on its potential protective and regulatory roles.
Gallic acid also serves as a building block for more complex molecules.
Ester derivatives such as propyl gallate and octyl gallate are synthesized from it.
These derivatives are widely used as antioxidants in food, cosmetics, and industrial products.
From a materials and chemical standpoint, gallic acid is valued for its reactivity combined with structural simplicity.
Its three hydroxyl groups make it a versatile platform for chemical modification.
This versatility supports its continued use in research, industry, and applied chemistry.
In microbiology studies, gallic acid has shown antimicrobial activity against certain bacteria and fungi.
Its mechanism may involve membrane disruption or oxidative stress modulation.
Research in this area continues to explore its bioactive potential.
Gallic acid is frequently used in chromatographic and spectrophotometric analysis.
It serves as a calibration standard for phenolic quantification.
This is especially common in total phenolic content assays.
In environmental chemistry, gallic acid can act as a natural reducing agent.
It influences redox balance in soil and aquatic systems.
Its presence may affect metal mobility and nutrient cycling.
Gallic acid also exhibits UV-absorbing properties, which contribute to its antioxidant and stabilizing roles.
This characteristic supports its inclusion in formulations aimed at oxidative protection.
Its aromatic ring structure enhances this light-absorbing capacity.
Gallic acid is a multifunctional phenolic compound with roles spanning plant biology, food science, analytical chemistry, and materials research.
Its combination of acidity, antioxidant behavior, and metal-binding capacity makes it chemically versatile.
This broad utility explains its continued scientific and industrial importance.
Uses:
Gallic acid is a potential bleaching agent and anti-oxidant, it is also astringent and potentially anti-microbial and anti-fungal.
Scientists are finding that gallic acid may serve as a skin-lightening agent by inhibiting the action of the tyrosinase and peroxidase enzymes.
Some studies indicate that it is more effective than hydroquinone when combined with the proper ingredients.
Gallic acid is also incorporated into anti-aging formulations for its ability to prevent mucopolysaccaride deterioration.
Gallic acid is a constituent of witch hazel and oak bark, among many other plants; however, it is generally obtained from nutgalls for commercial purposes.
Gallic acid is a cyclooxygease inhibitor substance found in plants. It has antioxidant, anti-inflammatory, and antineoplastic properties.
Gallic acid can be used to produce polyesters based on phloretic acid and gallic acid.
Gallic acid is widely used in food and beverage analysis as a reference compound.
It serves as the standard for measuring total phenolic content, commonly reported as gallic acid equivalents.
This application is essential in quality control of foods, teas, wines, and plant extracts.
In the food industry, gallic acid and its derivatives are used as antioxidants.
They help prevent oxidation, rancidity, and color degradation in fats and oils.
Ester derivatives such as propyl gallate are particularly important in this context.
Gallic acid is used in pharmaceutical and biomedical research for its antioxidant and bioactive properties.
It is studied for potential anti-inflammatory, antimicrobial, and protective effects.
These uses are mainly research-based rather than direct therapeutic applications.
In cosmetics and personal care products, gallic acid derivatives are used for antioxidant protection.
They help stabilize formulations and protect skin from oxidative stress.
Applications include creams, lotions, and anti-aging products.
Gallic acid is used in ink, dye, and pigment chemistry, especially in historical and specialty inks.
It is a key component in iron gall ink due to its metal-chelating ability.
This use remains relevant in conservation and restoration work.
In polymer and materials science, gallic acid is used as a building block for bio-based materials.
Its multiple hydroxyl groups enable crosslinking and functionalization.
This supports development of sustainable coatings, adhesives, and composites.
Gallic acid is applied in analytical and laboratory chemistry as a calibration and test compound.
It is used in redox studies, metal-complexation experiments, and antioxidant assays.
Its well-characterized behavior makes it a reliable laboratory standard.
In agriculture and plant science, gallic acid is studied for its role in plant defense and soil chemistry.
It is investigated as a natural antimicrobial and growth-modulating compound.
These applications are primarily experimental and research-focused.
Gallic acid is used in nutraceutical and functional ingredient research.
It is investigated as a natural antioxidant component in plant-based supplements.
These studies focus on stability, bioavailability, and synergistic effects with other polyphenols.
In cosmetic formulation research, gallic acid is explored for skin-protective functions.
It is studied for reducing oxidative stress linked to skin aging and environmental exposure.
This supports development of antioxidant-rich cosmetic actives.
Gallic acid is applied in antimicrobial and preservative research.
It is evaluated as a natural alternative to synthetic preservatives in food and cosmetic systems.
Gallic acids effectiveness is often studied in combination with other natural compounds.
In environmental and green chemistry, gallic acid is used as a bio-based reducing agent.
Gallic acid participates in the synthesis of metal nanoparticles, such as silver or gold nanoparticles.
These applications support sustainable and low-toxicity synthesis routes.
Gallic acid is used in enzyme inhibition and biochemical studies.
It serves as a probe molecule to study enzyme–polyphenol interactions.
This is relevant in drug discovery and metabolic research.
In wine, tea, and beverage research, gallic acid is used to study phenolic composition and aging.
In environmental and green chemistry, gallic acid is used as a bio-based reducing agent.
Gallic acid participates in the synthesis of metal nanoparticles, such as silver or gold nanoparticles.
These applications support sustainable and low-toxicity synthesis routes.
Gallic acid is used in enzyme inhibition and biochemical studies.
It serves as a probe molecule to study enzyme–polyphenol interactions.
This is relevant in drug discovery and metabolic research.
Gallic acid is also used in paper, leather, and natural tanning research.
Its interaction with proteins and fibers is studied to improve tanning and finishing processes.
These applications reflect its historical roots adapted to modern sustainable practices.
Safety Profile:
Gallic acid is generally considered to have low acute toxicity when handled under normal laboratory or industrial conditions.
Gallic acid is a naturally occurring phenolic compound commonly found in foods and plants.
Routine exposure at low levels is not expected to cause serious health effects.
Skin contact may cause mild irritation, especially with prolonged exposure or in sensitive individuals.
This is mainly due to its acidic and phenolic nature.
Protective gloves are recommended during handling.
Eye contact can result in irritation, redness, or stinging.
Accidental exposure should be rinsed immediately with plenty of water.
Eye protection is advised in laboratory and industrial settings.
Gallic acid inhalation of dust may cause respiratory tract irritation.
Symptoms can include coughing or throat discomfort if fine particles are inhaled.
Good ventilation and avoidance of dust generation are recommended.
Ingestion of large amounts may cause gastrointestinal irritation, such as nausea or stomach discomfort.
These effects are unlikely at normal exposure levels.
Medical attention should be sought if significant quantities are ingested.
Gallic acid is not flammable and does not present an explosion hazard.
However, thermal decomposition at high temperatures may produce irritating fumes.
Standard fire safety measures for organic solids are sufficient.
