Human serum albumin (HSA) and bovine serum albumin (BSA). Octyl gallate binds primarily to Sudlow site II (the ibuprofen binding site) on HSA. [2]
NADPH oxidase in polymorphonuclear neutrophils (PMNs). [1]
Herpes simplex virus type 1 (HSV-1) virions and infected cells. [3]

The antibacterial activity of octyl gallate against Helicobacter pylori has been reported, with a minimum inhibitory concentration (MIC) of 125 µg/mL[1].

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In cell-free antioxidant assays, Octyl gallate (G8) showed an EC50 of approximately 5 µM in the DPPH scavenging assay, demonstrating potent radical scavenging activity. [1]
In the Triene Degradation Assay (peroxyl radical ROO• scavenging), Octyl gallate (G8) was the most efficient molecule among tested gallates, presenting antioxidant activity about five-fold higher compared to other substances, with a Trolox equivalent antioxidant activity (TEAC) value approximately 1.2. [1]
Octyl gallate (10 µM) almost 100% abolished the production of superoxide anion radical by human PMNs stimulated with H. pylori, zymosan, or PMA, as measured by lucigenin-dependent chemiluminescence and WST-1 assays. In comparison, gallic acid inhibited around 20%. [1]
Octyl gallate (10 µM) showed a potent inhibitory effect on ROS produced by stimulated leukocytes (luminol-dependent chemiluminescence), with inhibition exceeding 90% regardless of stimulus (H. pylori, zymosan, PMA). [1]
In the NBT cytochemical assay, treatment with 10 µM Octyl gallate reduced formazan precipitate (indicating superoxide production) by 96% in PMA-stimulated PMNs. [1]
Octyl gallate (10 µM) provided a protective effect against PMA-induced morphological changes in neutrophils, including vacuolization and nuclear disruption. [1]
Octyl gallate at 10 µM significantly inhibited hypochlorous acid (HOCl) production by zymosan-stimulated PMNs. However, in a cell-free system using purified MPO and H2O2, Octyl gallate (G8) led to a significant increase in HOCl production. [1]
Octyl gallate demonstrated potent antibacterial activity against H. pylori with a MIC of 125 μg/mL and an MBC of 250 μg/mL. [1]
Octyl gallate (15 μM) suppressed the multiplication of HSV-1 in HEp-2 cells, decreasing the progeny virus yield by approximately 10,000-fold. [3]
Octyl gallate (15 μM) inhibited the multiplication of vesicular stomatitis virus (VSV, an RNA virus) in HEp-2 cells, decreasing the progeny virus yield to about one hundredth of the control. [3]
Octyl gallate inhibited the multiplication of poliovirus (an RNA virus) in HEp-2 cells, but with less sensitivity; a concentration of 60 μM was required for over 90% inhibition. [3]
Octyl gallate directly inactivated HSV-1 virions in a concentration-dependent manner (virucidal activity). At 50 μg/mL (approx. 178 μM), it reduced viral infectivity by over 90% after a 10-minute incubation at room temperature. It also inactivated VSV but did not inactivate poliovirus even at 200 μg/mL. [3]
Octyl gallate (15 μM) suppressed both the intracellular multiplication and the release of HSV-1 in HEp-2 cells, as shown in a one-step growth curve. [3]
Octyl gallate (15 μM) selectively accelerated the death of HSV-1-infected HEp-2 cells, as determined by trypan blue exclusion. [3]
The fluorescence of Octyl gallate was selectively enhanced in the presence of HSA and BSA. At a 1:1 molar ratio, it yielded approximately 49-fold and 11-fold increments in emission intensity with HSA and BSA, respectively (λex = 320 nm). [2]
The addition of ibuprofen (IP), which binds to Sudlow site II, to an Octyl gallate-HSA mixture completely suppressed the STD NMR signal and fluorescence enhancement of Octyl gallate, indicating it binds primarily to site II. Phenylbutazone (PB) did not inhibit the fluorescence enhancement. [2]

DPPH Radical Scavenging Assay: The antioxidant activity was evaluated by measuring the ability to scavenge the stable DPPH radical. Different concentrations of Octyl gallate were added to a DPPH methanolic solution. After incubation in the dark at room temperature for 30 minutes, the absorbance was measured at 517 nm. The EC50 value was obtained by linear interpolation from triplicate experiments. [1]
Triene Degradation (CAT) Assay: The peroxyl radical (ROO•) scavenging capacity was measured using an oil-water emulsion system. AAPH was used as a source of peroxyl radicals, which degrade eleostearic acid (a conjugated triene in tung oil), causing bleaching measured at 273 nm. The protective effect of Octyl gallate was evaluated by the lag phase it induced in the degradation curve. The area under the curve (AUC) was calculated, and the slope of (AUCsample - AUCcontrol) vs. concentration was compared to the slope for Trolox to determine the Trolox Equivalent Antioxidant Activity (TEAC). [1]
Myeloperoxidase (MPO)/H2O2 HOCl Production Assay: The effect of Octyl gallate on HOCl production was determined in a cell-free system. Reactions were performed in a 96-well plate by adding PBS, taurine (10 mM), MPO (10 nM), H2O2 (100 μM), and the test compound. The reaction was triggered by H2O2, incubated for 30 min at 37°C, and stopped by catalase. TMB solution was added, and the absorbance was measured at 630 nm to quantify taurine chloramine (a product of HOCl). [1]
Fluorescence Spectroscopy: Fluorescence analyses of Octyl gallate with proteins were conducted using a fluorescence spectrophotometer with 5/5 nm (excitation/emission) slit widths at λex = 280 nm and 10/5 nm slit widths at λex = 320 nm. [2]
Fluorescence Lifetime Measurement: Time-resolved quenching of protein fluorescence by Octyl gallate was measured using time-correlated single photon counting. The protein concentration was 4.0 μM and Octyl gallate was at 4.0 and 8.0 μM. Excitation and emission wavelengths were 280 and 345 nm, respectively. [2]
Circular Dichroism (CD) Spectroscopy: The effect of Octyl gallate on protein secondary structure was assessed using a CD spectrometer. Spectra were recorded at a constant HSA/BSA concentration of 2.0 μM with varying Octyl gallate concentrations (0 to 8.0 μM). Measurements were taken at 298 K in a 2 mm quartz cell from 250 nm to 190 nm with a step size of 1 nm. [2]
NMR Spectroscopy (STD and WATERGATE): The interaction between Octyl gallate and HSA was characterized using 1D WATERGATE and Saturation Transfer Difference (STD) NMR experiments on a 700 MHz Inova spectrometer at 298 K. The sample contained 0.01 mM HSA and 0.4 mM Octyl gallate. The WATERGATE spectrum was obtained with acquisition and relaxation times of 2 s and 32 scans. STD experiments used a 2 s Gauss pulse train with alternating irradiation frequency at -0.7 or -45 ppm, with 256 scans. [2]
Molecular Docking: The binding mode of Octyl gallate to HSA (Sudlow site II) was simulated using the CDOCKER docking program in Discovery Studio 3.1. The crystal structure of HSA (2BXG) was used. The 3D structure of Octyl gallate was generated and optimized. The pose with the lowest CDOCKER energy was chosen for analysis. [2]

PMN Isolation and ROS Measurement (Luminol-dependent Chemiluminescence): Human polymorphonuclear neutrophils (PMNs) were isolated from blood using a Histopaque-1077/1119 gradient. PMNs (1 x 10^6 cells/mL) were pre-incubated with Octyl gallate for 10 min at 37°C. Luminol (10 μM) and the stimulus (H. pylori, zymosan, or PMA) were added. Light emission was measured for 30-90 min using a luminometer. Integrated light emission was used to measure ROS production and calculate inhibitory potency relative to a control. [1]
Superoxide Anion Measurement (Lucigenin-dependent Chemiluminescence): Isolated PMNs (1 x 10^6 cells/mL) were pre-incubated with Octyl gallate for 10 min at 37°C. Lucigenin (10 μM) and the stimulus were added. Light emission was measured for 30-60 min using a luminometer to specifically measure superoxide anion radical production. [1]
Superoxide Anion Measurement (WST-1 Assay): Isolated PMNs (1 x 10^6 cells/mL) were pre-incubated with Octyl gallate for 10 min at 37°C. WST-1 (500 μM) and the stimulus were added. The extracellular release of superoxide was measured by the reduction of WST-1 to a soluble formazan, determined spectrophotometrically at 450 nm after 30-90 min of incubation. [1]
Nitroblue Tetrazolium (NBT) Assay: PMNs (1 x 10^6 cells/mL) were incubated with PMA (0.1 μM) and Octyl gallate (10 μM) for 30 min. NBT solution was added, and cells were incubated for another 30 min. Cells were then centrifuged onto glass slides (Cytospin), stained with May Grunwald-Giemsa, and observed under a microscope. The percentage of cells containing dark formazan granules (reduced NBT by superoxide) was established. [1]
Neutrophil Morphology Assay: PMNs (1 x 10^6 cells/mL) were pre-incubated with Octyl gallate (10 μM) for 10 min, then activated with PMA (0.1 μM) for 30 min. Cells were centrifuged onto glass slides, stained with May Grunwald-Giemsa, and observed under an optical microscope to evaluate vacuolization and nuclear disruption as a measure of NADPH oxidase activation and protection. [1]
Hypochlorous Acid Production (Activated Neutrophils): PMNs (2 x 10^6 cells/mL) were pre-incubated for 10 min at 37°C in PBS containing 10 mM taurine and Octyl gallate. Cells were stimulated with PMA or zymosan for 30-90 min. The reaction was stopped with catalase. The supernatant was transferred, and TMB solution was added. The resulting oxidation product was detected spectrophotometrically at 630 nm to measure taurine chloramine (produced by HOCl). [1]
Antibacterial Assay (Broth Microdilution for MIC): H. pylori (ATCC 43504) suspension (10^6 CFU/mL) was added to wells of a 96-well plate containing BHI broth with 10% fetal bovine serum and various concentrations of Octyl gallate (final concentrations 62.5 to 1000 μg/mL). The plate was incubated at 36-37°C in a microaerophilic atmosphere (10% CO2) for 72 hours. Bacterial growth was determined by spectrophotometric reading at 630 nm before and after incubation. The MIC was defined as the lowest concentration that inhibited bacterial growth by more than 90%. An aliquot from each well was transferred to agar plates to determine the Minimum Bactericidal Concentration (MBC). [1]
Viral Growth Inhibition (Virus Yield Assay): Confluent monolayers of HEp-2 or Vero cells were infected with HSV-1, VSV, or poliovirus at a specified MOI. Infected cells were incubated at 37°C in serum-free MEM with 0.1% BSA and various concentrations of Octyl gallate. After incubation (e.g., 24 h for HSV-1), the total progeny virus (cells + medium) was harvested by freezing and thawing. The number of infectious virus particles was determined by a plaque assay on Vero cells. [3]
Direct Virucidal Activity Assay: A virus preparation (10^5 PFU of HSV-1 in PBS with 1% calf serum) was mixed with various concentrations of Octyl gallate and incubated for 10 min at room temperature. The mixture was then diluted with ice-cold PBS, and the remaining infectious virus was measured by a plaque assay on Vero cells. [3]
Cytopathic Effect (CPE) and Cell Death Determination: HEp-2 cells were mock-infected or infected with HSV-1 and incubated in the presence or absence of Octyl gallate (15 μM). The CPE was determined by microscopic observation of rounded cells. For cell death determination, cells were trypsinized, and the numbers of living and dead cells were determined by the trypan blue dye-exclusion method. [3]
Time of Addition Experiment: HEp-2 cells infected with HSV-1 were incubated in medium without the reagent. At various times post-infection (p.i.), Octyl gallate was added to the culture medium at a final concentration of 14.2 μM (4 μg/mL). At 23 h p.i., the total progeny virus in each culture was assayed to determine the reagent-sensitive step in the viral multiplication cycle. [3]

In HEp-2 cells, the cytotoxicity of Octyl gallate was relatively moderate compared to gallates with longer alkyl chains. At a concentration of 15 μM (approx. 4.2 μg/mL), it induced moderate cell death in uninfected HEp-2 cells after 24 or 36 hours of incubation, as measured by trypan blue exclusion. It also induced significant cytoplasmic effects (rounding, shrinkage, detachment) in HEp-2 cells regardless of virus infection. [3]
The FAO/WHO Joint Expert Committee on Food Additives (JECFA) established an acceptable daily intake (ADI) for man of 0.2 mg/kg body weight (as a sum of propyl, octyl, and lauryl gallate). [1]
It was demonstrated that alkyl esters of gallic acid, including Octyl gallate, can inhibit pyruvate carboxylation and lactate gluconeogenesis, with Octyl gallate being the more effective inhibitor, highlighting its potential toxic effect to the liver. [1]

[1]. Octyl gallate, a food additive with potential beneficial properties to treat Helicobacter pylori infection. Food Funct. 2017 Jul 19;8(7):2500-2511.

[2]. Octyl gallate: An antioxidant demonstrating selective and sensitive fluorescent property. Food Chem. 2017 Mar 15;219:268-273.

[3]. Antiviral effect of octyl gallate against DNA and RNA viruses. Antiviral Res. 2007 Feb;73(2):85-91.

Octyl gallate is a gallic acid ester formed by the condensation of the carboxyl group of gallic acid and the hydroxyl group of octanol. It functions as a food antioxidant, plant metabolite, and hypoglycemic agent. Octyl gallate is an antioxidant used in margarine. Studies have shown that octyl gallate has antiviral properties (A7906).

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Octyl gallate is a widely used food additive in the food industry. The study highlights it as a promising molecule in the treatment of H. pylori infection due to its dual anti-ROS and anti-H. pylori activity, which is crucially dependent on its hydrophobicity. [1]
Octyl gallate is an internationally recognized antioxidant, with maximum permitted levels in foods in the EU ranging from 25 to 400 mg/kg. [2]
In Japan, Octyl gallate is recognized as a quasi-drug by the Ministry of Health, Labour and Welfare. [3]
The selective and sensitive fluorescent property of Octyl gallate in the presence of HSA can be used to determine its concentration via the standard addition method, which must be performed under certain conditions (e.g., using corresponding blank food samples). [2]

C15H22O5

282.3322

282.146

1034-01-1

61253

White to off-white solid powder

1.2±0.1 g/cm3

482.9±40.0 °C at 760 mmHg

101-104 °C(lit.)

177.1±20.8 °C

0.0±1.3 mmHg at 25°C

1.552

5.26

3

5

9

20

269

0

NRPKURNSADTHLJ-UHFFFAOYSA-N

InChI=1S/C15H22O5/c1-2-3-4-5-6-7-8-20-15(19)11-9-12(16)14(18)13(17)10-11/h9-10,16-18H,2-8H2,1H3

octyl 3,4,5-trihydroxybenzoate

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 : ~125 mg/mL (~442.74 mM)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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