Leukotriene B4 12-hydroxydehydrogenase (LTB4DH) – Induces LTB4DH expression (synergistically with calycosin or formononetin) [3]
Gallic acid targets multiple molecular pathways and enzymes. It is a well-characterized inhibitor of cyclooxygenase-2 (COX-2), an enzyme involved in inflammation and prostaglandin synthesis. The compound also targets carbonic anhydrases, FUT7, P4H, and histone acetyltransferases (HATs) including Tip60 and PCAF. As a free radical scavenger, gallic acid neutralizes reactive oxygen species and protects cells from oxidative stress. Its antioxidant activity is linked to its ability to modulate radical-mediated pathways. The compound has multi-affinity drug properties, interacting with numerous cellular targets to exert its diverse biological effects.

COX-2 is inhibited by the antioxidant gallic acid[1]. Following an 18-hour gallic acid treatment, 26.4% of the neutrophils that required treatment—or 40.3% of the total—were still alive after treatment. Cumene cannot be broken down by gallic acid and myocyte lysis cannot occur [3].

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- In HepG2 cells, gallic acid (8 μg/mL) alone did not induce LTB4DH mRNA expression; but in combination with Radix Astragali extracts or calycosin (10 μg/mL) or formononetin (10 μg/mL), it synergistically induced LTB4DH expression after 24 h treatment [3]
- In human neutrophils, gallic acid (8 μg/mL) combined with calycosin (10 μg/mL) induced LTB4DH mRNA expression in a time-dependent manner (detectable after 6 h) [3]
- In human neutrophils, gallic acid (8 μg/mL) alone showed weak LTB4DH induction; combination with calycosin (10 μg/mL) or formononetin (10 μg/mL) significantly increased LTB4DH mRNA expression (p < 0.001) [3]
- Gallic acid (8 μg/mL) combined with calycosin (10 μg/mL) diminished LTB4 (100 nM)-induced neutrophil survival: after 18 h treatment, viable neutrophils decreased from 40.3% (LTB4 alone) to 27.7% (combination), comparable to untreated control (26.4%) [3]
- Gallic acid (8 μg/mL) combined with calycosin (10 μg/mL) inhibited LTB4-induced neutrophil chemotaxis in a TransWell assay (pore size 8 μm) after 24 h pre-treatment; combination showed strongest inhibition against 10 nM and 100 nM LTB4 [3]
Gallic acid exhibits potent in vitro anticancer activity, inducing apoptosis in human lung cancer cells and demonstrating cytotoxicity against PC14 and MKN45 human cancer cell lines. The combination of gallic acid with cisplatin increases tumor cell apoptosis compared to cisplatin treatment alone, suggesting synergistic potential for lung cancer therapy. Gallic acid shows antimicrobial, antioxidant, anti-inflammatory, and anticancer activities in various in vitro models. Its cytotoxic activity is related to its radical modulating activity, and the compound induces apoptosis through multiple different mechanisms. The compound also exhibits COX-2 inhibitory activity in biochemical assays.

The gallic acid group's body weight (2.5±0.69 g, p=0.76) and food approval amount (2.6±0.08 g/day, p=0.69) differed substantially from the body weight (food approval amount: 2.41±0.14 g/day and body weight: 2.83±0.84 g/day). After two weeks of treatment, there was a considerable improvement in the gallic acid group's blood pressure tolerance. After two weeks of therapy, the gallic acid group's blood pressure tolerance was also significantly lowered, with tachycardia observed at 90 and 120 minutes (p<0.05). The group's serum triglyceride concentration was significantly lower in the gallic acid group (0.67±0.03 mM, p<0.05) than in the Manhattan group (1.08±0.20 mM). Gallic acid (3.01±0.18 mM) and Manhattan (3.19±0.27 mM). the overall depth enrichment of the group [2].

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- In isoproterenol-induced mouse model of myocardial infarction (male C57BL/6 mice, 6-8 weeks, 20-22 g), gallic acid (8 mg/kg/day, i.p. for 3 days) alone failed to attenuate isoproterenol-induced myocytolysis (H&E staining). However, combination with calycosin (40 mg/kg/day, i.p.) synergistically preserved cardiac morphology [3]
- Gallic acid alone (8 mg/kg/day, i.p.) showed inhibitory effect on isoproterenol-induced neutrophil infiltration (Ly6G immunohistochemistry), but combination with calycosin (40 mg/kg/day) synergistically reduced infiltration (p < 0.05) [3]
- Gallic acid alone did not significantly reduce isoproterenol-induced increase in myeloperoxidase (MPO) activity; combination with calycosin significantly reduced MPO activity (p < 0.05) [3]
- Gallic acid alone (8 mg/kg/day) effectively reduced isoproterenol-induced increase in malondialdehyde (MDA) levels (p < 0.05); combination with calycosin also showed significant reduction (p < 0.01) [3]
In vivo, gallic acid has demonstrated glucose tolerance improvement and triglyceride concentration reduction in diet-induced obesity mice. It attenuates neutrophil infiltration and subsequent injury in isoproterenol-induced myocardial infarction through a mechanism possibly involving leukotriene B4 12-hydroxydehydrogenase. The compound exhibits anti-inflammatory effects in various animal models. Its antioxidant properties contribute to protective effects against oxidative stress-related diseases, including cardiovascular disorders and neurodegeneration. Gallic acid has been evaluated for its potential in cancer prevention and therapy in preclinical models.

Gallic acid's in vitro enzyme inhibition is typically assessed using COX-2 enzymatic activity assays, where the compound's ability to inhibit prostaglandin synthesis is measured. Molecular docking studies have been performed to analyze the structural interactions between gallic acid and the COX-2 active site. Enzyme inhibition assays for other targets such as carbonic anhydrases and histone acetyltransferases can be conducted using purified enzymes and appropriate substrates. The compound's free radical scavenging activity is evaluated using standard antioxidant assays such as DPPH, ABTS, or FRAP. These cell-free assays provide quantitative data on the compound's potency against various molecular targets.

- HepG2 cells were seeded in 6-well plates overnight and treated with gallic acid (8 μg/mL) alone or in combination with herbal fractions, calycosin (10 μg/mL), or formononetin (10 μg/mL) for 24 h. Total RNA was extracted and RT-PCR was performed for LTB4DH mRNA detection [3]
- Human neutrophils were freshly isolated and treated with gallic acid (8 μg/mL) and calycosin (10 μg/mL) in combination for 0, 3, 6, 9, and 18 h. RT-PCR was used to detect LTB4DH mRNA expression [3]
- Human neutrophils were treated with LTB4 (100 nM) alone or combined with gallic acid (8 μg/mL) and calycosin (10 μg/mL) for 3, 6, 9, and 18 h. Apoptosis was analyzed by Annexin V-FITC/PI staining and flow cytometry [3]
- Human neutrophils were pre-treated with gallic acid (8 μg/mL) and calycosin (10 μg/mL) individually or in combination for 24 h. Cells were labeled with Calcein AM (5 μM) and chemotaxis was assayed using TransWell plates (8 μm pore) toward LTB4 (0, 10, 100 nM) for 3 h. Migrated cells were quantified by fluorescence (ex/em 485/530 nm) [3]
In vitro cell-based assays for gallic acid involve treating cancer cell lines (such as PC14 lung cancer cells and MKN45 gastric cancer cells) with varying concentrations of the compound to assess cytotoxicity and apoptosis induction. Cell viability is measured using MTT, CCK-8, or similar colorimetric assays. Apoptosis is quantified through flow cytometry using Annexin V/PI staining or by measuring caspase activity. Combination studies with cisplatin are performed to evaluate synergistic effects. The compound's anti-inflammatory activity is assessed in immune cells by measuring cytokine production. Antioxidant activity in cells is evaluated by measuring reactive oxygen species levels using fluorescent probes.

- Male C57BL/6 mice (6-8 weeks, 20-22 g) were randomly divided into 5 groups (n=6): Control (saline + vehicle, i.p., 0.5 mL/day for 3 days); ISO group (saline i.p. day1, then isoproterenol 100 mg/kg/day s.c. day2-3); ISO+GA (gallic acid 8 mg/kg/day i.p. for 3 days + isoproterenol 100 mg/kg/day s.c. day2-3); ISO+CA (calycosin 40 mg/kg/day i.p. for 3 days + isoproterenol day2-3); ISO+CA+GA (calycosin 40 mg/kg/day + gallic acid 8 mg/kg/day i.p. for 3 days + isoproterenol day2-3). Isoproterenol dissolved in 0.9% saline; gallic acid dissolved in 5% ethanol in 0.9% saline. Isoproterenol injected 10 min after drug injection [3]
- Half of animals from each group were euthanized by pentobarbital (200 mg/kg, i.p.) and fixed with 4% paraformaldehyde. Heart tissues were paraffin-embedded, sectioned (5 μm), and stained with H&E for histopathology [3]
- For immunohistochemistry, cardiac sections were boiled in citrate buffer (pH=6) for 15 min, blocked in 5% goat serum for 1 h, probed with anti-Ly6G primary antibody (1:50) at 4°C overnight, then incubated with FITC-conjugated secondary antibody (1:200) for 1.5 h at room temperature. Images acquired by laser scanning microscope [3]
- Frozen hearts were homogenized in PBS (pH 6.0) with 0.5% hexadecyltrimethylammonium hydroxide, centrifuged at 12,000 rpm for 20 min at 4°C. Supernatants were used for MPO activity and MDA level assays. Protein concentration determined by Bio-Rad protein assay [3]
In vivo animal experiments for gallic acid have been conducted in diet-induced obesity mouse models to assess its effects on glucose tolerance and triglyceride levels. The compound is typically administered orally or via intraperitoneal injection. In isoproterenol-induced myocardial infarction models, gallic acid's cardioprotective effects have been evaluated by measuring neutrophil infiltration and tissue injury. Tumor xenograft models in immunodeficient mice have been used to assess anticancer efficacy. Doses typically range from 10 to 100 mg/kg depending on the study and route of administration. Efficacy endpoints include biomarker analysis, histopathology, and functional assessments.

Absorption, Distribution and Excretion
Easily absorbed from the gastrointestinal tract. After administration to rabbits, most of it is excreted unchanged in the urine, but small amounts are also excreted as pyrogallic acid and 4-methoxy-3,5-dihydroxybenzoic acid. Metabolism/Metabolites Gallic acid…is methylated to 3,5-dihydroxy-4-methoxybenzoic acid by catechol-O-methyltransferase. This enzyme is located in the sol component and is present in the liver, kidneys, skin, blood cells, glandular tissue, and nerve fibers. It requires S-adenosylmethionine as a methyl donor, as well as Mg++ or other divalent ions. After administration to rabbits, most of it is excreted unchanged in the urine, but small amounts are also excreted as pyrogallic acid and 4-methoxy-3,5-dihydroxybenzoic acid. After metabolism by intestinal flora, gallic acid is decarboxylated to pyrogallic acid. Gallic acid is converted into gallic acid-β-D-glucuronide in rabbits. /Excerpt from table/
Gallic acid is a small, hydrophilic phenolic compound with a molecular weight of 170.12. It is highly soluble in water, ethanol, and methanol, facilitating its use in various experimental systems. The compound is metabolized and excreted primarily through the kidneys. As a natural polyphenol, its oral bioavailability is moderate due to extensive first-pass metabolism, though it reaches systemic circulation at concentrations sufficient for biological activity. It is a minor (approximately 1%) product of the metabolic breakdown of aspirin, excreted in urine. The compound is stable under recommended storage conditions and is typically stored at room temperature or -20°C for long-term preservation.

Non-Human Toxicity Values
Rabbit oral LD50: 5.0 g/kg
Gallic acid is generally considered to have a favorable safety profile as a natural compound found in many foods and traditional medicines. However, the compound can cause skin and strong eye irritation. It is harmful by ingestion and skin absorption, and there is evidence of reproductive toxicity in experimental animals. The compound's safety has been evaluated in various animal models, with toxicity typically observed at high doses. In cell culture, gallic acid exhibits concentration-dependent cytotoxicity, with the therapeutic window depending on the cell type and experimental conditions. Proper safety precautions should be taken when handling the compound in research settings.

[1]. COX-2 structural analysis and docking studies with gallic acid structural analogues. Springerplus. 2012 Dec;1(1):58.

[2]. Gallic acid improves glucose tolerance and triglyceride concentration in diet-induced obesity mice. Scand J Clin Lab Invest. 2013 Dec;73(8):607-14.

[3]. Plant Natural Products Calycosin and Gallic Acid Synergistically Attenuate Neutrophil Infiltration and Subsequent Injury in Isoproterenol-Induced Myocardial Infarction: A Possible Role for Leukotriene B4 12-Hydroxydehydrogenase? Oxid Med Cell Longev. 2015;2015:434052.

Gallic acid is an odorless white solid that sinks in water. (US Coast Guard, 1999)
Gallic acid is a trihydroxybenzoic acid, with hydroxyl groups located at positions 3, 4, and 5. It possesses astringent, cyclooxygenase 2 inhibitor, plant metabolite, antioxidant, antitumor agent, human xenobiotic metabolite, EC 1.13.11.33 (arachidonic acid 15-lipoxygenase) inhibitor, apoptosis inducer, and anti-aging effects. It is the conjugate acid of gallic esters.
Gallic acid is a metabolite found or produced in Escherichia coli (K12 strain, MG1655 strain).
Gallic acid has been reported in Polygonum cuspidatum, tea trees, and other organisms with relevant data.
Gallic acid is a metabolite found or produced in Saccharomyces cerevisiae.
A colorless or slightly yellow crystalline compound extracted from Gallus gallus domesticus. It is used in photography, pharmaceuticals, and as an analytical reagent. See also: Gallic acid monohydrate (active ingredient); Paeonia lactiflora root (partial); Whole plant of Porcine hepatitis (partial)... See more...

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Therapeutic Uses
Veterinary Drug: Formerly used as an intestinal astringent.
Veterinary Drug: Antidiarrheal drug

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- Gallic acid was previously isolated from Radix Paeoniae Rubra through a bioactivity-guided fractionation procedure [3]
- Gallic acid alone does not induce LTB4DH expression; it requires combination with calycosin or formononetin for synergistic induction [3]
- The combination of gallic acid and calycosin represents a novel “multidrugs on one target” strategy for treating neutrophil-mediated myocardial injury [3]
Gallic acid is a natural polyhydroxyphenolic compound with diverse pharmacological activities including antimicrobial, antioxidant, anti-inflammatory, and anticancer properties. It functions as a free radical scavenger and COX-2 inhibitor. The compound has shown promise in combination with cisplatin for enhanced lung cancer therapy. Gallic acid is a metabolite of salicylic acid degradation and is excreted in urine. It is found naturally in various plants and has been used in traditional medicine. The compound is also known as 3,4,5-trihydroxybenzoic acid. Its multi-target effects and natural origin make it an attractive compound for pharmacological research.

C7H6O5

170.12

170.021

149-91-7

Gallic acid hydrate;5995-86-8;Gallic acid-d2;294660-92-7

370

White to off-white solid powder

1.7±0.1 g/cm3

501.1±50.0 °C at 760 mmHg

252 °C (dec.)(lit.)

271.0±26.6 °C

0.0±1.4 mmHg at 25°C

1.730

0.91

4

5

1

12

169

0

C1=C(C=C(C(=C1O)O)O)C(=O)O

LNTHITQWFMADLM-UHFFFAOYSA-N

InChI=1S/C7H6O5/c8-4-1-3(7(11)12)2-5(9)6(4)10/h1-2,8-10H,(H,11,12)

3,4,5-trihydroxybenzoic acid

HSDB2117; HSDB 2117; Gallic acid; 3,4,5-Trihydroxybenzoic acid; 149-91-7; Benzoic acid, 3,4,5-trihydroxy-; Gallic acid, tech.

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ≥ 100 mg/mL (~587.82 mM)
H2O : ~8.33 mg/mL (~48.97 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (14.70 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (14.70 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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 (Please use freshly prepared in vivo formulations for optimal results.)