Octyl Gallate Research Articles

Exploring the thermochromic properties of fluoran-based complexes: Synthesis, structural influence, and application in temperature sensing

Fluoran dyes are extensively used as key components of thermochromic materials. To expand the scope of fluoran-based thermochromic systems, we conducted a comprehensive study to explore the relationships between the thermochromic properties of three-component complexes and the types and ratios of their constituents: fluoran dyes, developers, and solvents. We synthesized twenty-one fluoran dyes with varied chemical structures, including differences in the carbon chain length of the dialkylamino group, substitutions with electron-donating and electron-withdrawing groups, and the enlargement of conjugation systems. By combining these dyes with several phenolic developers and three long-chain alcohols, we prepared numerous thermochromic complexes and evaluated their color-changing behaviors under temperature variations. Complexes utilizing developers, bisphenol (BPA), bisphenol S (BPS), 4-hydroxy-4′-isopropoxydiphenylsulfone (D-8), 2,4′-dihydroxydiphenyl sulfone (2, 4′-BPS), and octyl gallate (OG) exhibited a red-to-colorless transition with increasing temperature, whereas those with developer lauryl gallate (LG) displayed a colorless-to-red transition upon heating. The chain length and conjugation extension of fluoran dyes influenced the optimal ratio of the three components. Additionally, substituents on the xanthene moiety of fluoran dyes didn't impact their complex performance. Finally, we demonstrated the fabrication of these thermochromic complexes on filter papers, showcasing their sensitivity to temperature fluctuations and highlighting their potential application as temperature sensors.

Antimicrobial and anti-biofilm activities of octyl gallate against Shewanella putrefaciens and Listeria monocytogenes

Shewanella putrefaciens and Listeria monocytogenes are concerned by scientists and consumers due to their ability to produce dense biofilms to contaminate and cause food spoilage. The object of this study was to investigate the antimicrobial and anti-biofilm activities of octyl gallate (OG) against the two food-related bacteria. Results showed that the antimicrobial activities of OG were in a dose-dependent manner and the minimum inhibitory concentration (MIC) of S. putrefaciens and L. monocytogenes were 0.2 mmol/L and 0.1 mmol/L, respectively. OG can rapidly penetrate the bacteria and produce reactive oxygen species (ROS). Then, OG and ROS can lead to membrane damage and cell rupture, causing DNA and protein leakage. Our data also strongly suggested that OG not only can inhibit biofilms formation, but also eradicate the performed biofilms. Furthermore, it was shown that OG, as an additive, has great potential in antimicrobial application to prolong the shelf life of large yellow croakers. These prove that OG can combat bacteria and eradicate biofilm against S. putrefaciens and L. monocytogenes.

Broad-Spectrum Antibacterial Activity of Antioxidant Octyl Gallate and Its Impact on Gut Microbiome.

In this study, we investigated the antibacterial activity of octyl gallate (OG), an antioxidant food additive, against both Gram-positive and Gram-negative bacterial pathogens. OG demonstrated robust bactericidal activity against Gram-positive bacterial pathogens with minimum inhibitory concentrations (MIC) of 4 to 8 µg/mL and minimum bactericidal concentrations (MBC) of 8 to 16 µg/mL in vitro. However, OG exhibited limited antibacterial activity against Gram-negative bacteria, including E. coli, although it could inhibit bacterial growth in vitro. Importantly, OG administration in mice altered the fecal microbiome, significantly reducing microbial diversity, modifying community structure, and increasing the abundance of beneficial bacteria. Additionally, OG displayed low cytotoxicity and hemolytic activity. These findings suggest that OG could be developed as a novel antibacterial agent, particularly against multi-drug-resistant MRSA. Our results provide new insights into the therapeutic potential of OG in modulating the gut microbiome, especially in conditions associated with microbial imbalance, while ensuring food safety.

Controlled release characteristics of alkyl gallates and gallic acid from β-cyclodextrin inclusion complexes of alkyl gallates

The freeze-drying approach was used to create inclusion complexes utilizing alkyl gallates and β-cyclodextrin, namely dodecyl gallate, octyl gallate, butyl gallate, and ethyl gallate, which are exemplary examples of phenolic esters. The everted-rat-gut-sac model demonstrated that the inclusion complexes released alkyl gallates, which were subsequently hydrolyzed to generate free gallic acid, as evidenced by HPLC-UV analysis. Both gallic acid and short-chain alkyl gallates were capable of permeating the small intestinal membrane. The transport rate of gallic acid (or alkyl gallates) exhibited an initial rise followed by a drop when the carbon-chain lengths varied. The inclusion complex groups exhibited a superior sustained-release effect compared to the comparable alkyl gallates groups, thus possibly leading to higher bioavailability and stronger bioactivity. Moreover, altering the length of the carbon chain will allow for the effortless achievement of regulated release of phenolic compounds and short-chain phenolic esters from such β-cyclodextrin inclusion complexes.

Supplemental Patch Testing Identifies Allergens Missed by Standard Screening Series.

Background: Supplemental patch testing is an adjunct to standard patch test screening series. Objective: To determine the demographics, characteristics, frequency, relevance, and interpretation of patch test reactions for supplemental patch testing. Methods: Retrospective study of patients tested 2017-2020 with North American Contact Dermatitis Group (NACDG) and supplemental screening series (Supplemental Series A [SSA], Supplemental Series B [SSB]). Demographics, characteristics, reaction strengths, relevance, and final interpretation were recorded. Results: Cohort included 791 patients; 73.5% female, 68.6% age >40 years. 74.1% were White, 15.2% Black, 5.7% Asian, and 1.5% Hispanic. The most common Dermatitis sites were scattered/generalized (27.2%), face (24.0%), and hands (23.5%). For 2017-2018 and 2019-2020, respectively, 82% (318/388) and 78.4% (316/403) had ≥1 "allergic" reaction. In addition, 13.5% (52/385) and 11.7% (47/403) had SSA reactions, and 38.1% (115/302) and 31.5% (101/321) had SSB reactions. In the 87 (2017-2018) and 99 (2019-2020) patients with negative NACDG testing, 17 (19.5%) and 12 (12.1%) had supplemental reactions. Of the 34 supplemental allergens with reaction frequency ≥1%, 58.8% (20/34) are not part of the American Contact Dermatitis Society 90 (2020) or NACDG 2021-2022 screening series. The highest frequency allergens from this group were dodecyl and octyl gallate, cinnamic alcohol, phenyl salicylate, hexahydro-1,3,5-tris-(2-hydroxyethyl) triazine, and abitol. Conclusions: Supplemental patch testing identifies additional relevant allergens in patients with suspected allergic contact Dermatitis.

Identification of octyl gallate, a novel apoptosis-inducing compound for colon cancer therapy, from Sanguisorba officinalis L. by cell membrane chromatography and UHPLC-(Q)TOF-MS/MS

Colon cancer is a common gastrointestinal malignancy that ranks third in incidence among gastrointestinal cancers. Therefore, screening bioactive compounds for treatment of colon cancer is urgently needed. Sanguisorba officinalis L. (SO) has been demonstrated that the extractions or monomers possess potential anti-tumor effect. In this study, we firstly used cell membrane chromatography (CMC) and ultra-performance liquid chromatography coupled with (quadrupole) time-of-flight mass spectrometry (UHPLC-(Q) TOF-MS/MS) to identify a novel active ingredient, octyl gallate (OG), from SO methanol extract (SO-MtOH). HCT116 and SW620 cells lines were used for in vitro research, which showed OG presents great anti-colon cancer effect by inhibiting proliferation, inducing apoptosis, and repressing the migration and invasion. Furthermore, SW620 bearing athymic nude mice was used to investigate the potential antitumor activity in vivo, which exhibited OG treatment remarkably lessened the tumor volume. Mechanism studies showed that OG downregulated the PI3K/AKT/mTOR signaling axis and induced apoptosis by upregulating the Bax/Bcl-2 protein and the cleaved caspase-3, caspase-9. In conclusion, our research innovatively applied the method of CMC to intriguingly unearth the potential anti-colon cancer ingredient OG and demonstrated its the great antineoplastic activity, which provide a new insight for researchers efficiently developing the novel apoptosis-inducing compound for colon cancer therapy.

Antimicrobial Effect of Lippia citriodora Extract in Combination with Gallic Acid or Octyl Gallate on Bacteria from Meat.

Chicken meat and its derivatives are easily alterable. They are a nutritionally healthy food, and their consumption has seen a remarkable increase worldwide in recent years. At the same time, consumer demand for the use of natural products to control microbial growth is increasing. In this context, the antimicrobial capacity of a commercial extract of the lemon verbena (Lippia citriodora) plant, (LCE) was tested in binary combination with gallic acid or octyl gallate against two strains of lactic acid bacteria (LAB) of meat origin: Carnobacterium divergens ATCC 35677 and Leuconostoc carnosum ATCC 49367. First, the antimicrobial potential was evaluated by the checkerboard microdilution method at the optimal growth temperature of each and at 4 °C, pH 5.7 and 6.7, in culture medium. Octyl gallate was the most effective antimicrobial against the two bacteria under all study conditions. At 4 °C, the combination of LCE with octyl gallate had a similar antimicrobial effect on the two LAB, being bactericidal at pH 6.7. In chicken breast, this effective combination was tested in normal or modified atmosphere and refrigerated (4-8 °C) for 9 days. LCE + OG in modified atmosphere reduced the different microbial groups studied, including the lactic acid bacteria as the main microorganisms responsible for the spoilage of fresh meat. Further research could pave the way for the development of novel strategies contributing to the technological stability, security, and functional properties of chicken meat.

Mechanisms and quality variations of non-volatile and volatile metabolites in black tea from various ages of tea trees: Insights from metabolomics analysis

The sensory quality of black tea (BT) influenced by various factors, among which tree age is particularly significant. People prefer BT produced by fresh leaves from old tea trees, yet the correlation between tree age and tea quality has not been thoroughly investigated. In this study, we analyzed the quality of BT from young trees (H-JYH) and old trees (H-OJYH) using e-tongue technology and sensory evaluation. Our findings revealed that H-OJYH had stronger sweetness and sourness, richer flavor, and diminished bitter-astringency compared to H-JYH. 1231 non-volatile metabolites and 504 volatile metabolites were discovered by ultra-performance liquid chromatography (UPLC) and gas chromatography–mass spectrometry (GC–MS). L-tartaric acid and trans-citridic acid were found to contribute to increase acidity, and 7,8-dihydroxy-6-methoxycoumarin and d-fructose 6-phosphate were associated with enhanced sweetness in H-OJYH. Additionally, lower levels of octyl gallate and vanillic acid in H-OJYH contributed to the diminished bitter-astringency. β-ionone, 2-phenylethanol and phenylacetaldehyde merged as characteristic compounds of older tree BT with stronger floral and sweet aroma. Our study serves as a guideline to explore the relationship between tree age and tea quality.

Ascorbic acid potentiates photodynamic inactivation mediated by octyl gallate and blue light for rapid eradication of planktonic bacteria and biofilms

This study reported for the first time that Ascorbic acid (AA) could appreciably boost the efficiency of Octyl gallate (OG)-mediated photodynamic inactivation (PDI) on Escherichia coli and Staphylococcus aureus in planktonic and biofilm states. The combination of OG (0.075 mM) and AA (200 mM) with 420 nm blue light (212 mW/cm2) led to a >6 Log killing within only 5 min for E. coli and S. aureus and rapid eradication of biofilms. The mechanism of action appears to be the generation of highly toxic hydroxyl radicals (•OH) via photochemical pathways. OG was exposed to BL irradiation to generate various reactive oxygen radicals (ROS) and the addition of AA could transform singlet oxygen (1O2) into hydrogen peroxide (H2O2), which could further react with AA to generate enormous •OH. These ROS jeopardized bacteria and biofilms by nonspecifically attacking various biomacromolecules. Overall, this PDI strategy provides a powerful microbiological decontamination modality to guarantee safe food products.

Simulating the behavior of antioxidant to explore the mechanisms of oxidative stability in Pickering emulsion

This study explores effective strategies for bolstering emulsion oxidative stability via optimized interfacial distribution of varying hydrophobicity antioxidants (gallic acid, propyl gallate, octyl gallate) in zein nanoparticle (ZP) stabilized Pickering emulsions. Experimental and simulation methods revealed that antioxidant (AO) with higher hydrophobicity or loaded into ZP demonstrated stronger hydrogen bonding and van der Waals interactions with ZP. This increased interfacial loading of antioxidants resulted in improved oxidative stability in Pickering emulsions. The flow, distribution and orientation of AO, as revealed by dissipative dynamics simulations, highlighted the role of hydrophobic interactions during initial AO migration, influenced by varied alkyl chain lengths. Subsequent interface rearrangements arose from conservative force interactions between the AO's phenol hydroxyl ends and ZP. These findings inform effective interfacial engineering to optimize antioxidant efficiency, guiding practical applications in emulsion systems for improved oxidative stability.

Targeted inhibition of gut bacterial β-glucuronidases by octyl gallate alleviates mycophenolate mofetil-induced gastrointestinal toxicity

Mycophenolate mofetil (MMF) is a viable therapeutic option against various immune disorders as a chemotherapeutic agent. Nevertheless, its application has been undermined by the gastrotoxic metabolites (mycophenolic acid glucuronide, MPAG) produced by microbiome-associated β-glucuronidase (βGUS). Therefore, controlling microbiota-produced βGUS underlines the potential strategy to improve MMF efficacy by overcoming the dosage limitation. In this study, the octyl gallate (OG) was identified with promising inhibitory activity on hydrolysis of PNPG in our high throughput screening based on a chemical collection of approximately 2000 natural products. Furthermore, OG was also found to inhibit a broad spectrum of BGUSs, including mini-Loop1, Loop 2, mini-Loop 2, and mini-Loop1,2. The further in vivo experiments demonstrated that administration of 20 mg/kg OG resulted in predominant reduction in the activity of BGUSs while displayed no impact on the overall fecal microbiome in mice. Furthermore, in the MMF-induced colitis model, the administration of OG at a dosage of 20 mg/kg effectively mitigated the gastrointestinal toxicity, and systematically reverted the colitis phenotypes. These findings indicate that the OG holds promising clinical potential for the prevention of MMF-induced gastrointestinal toxicity by inhibition of BGUSs and could be developed as a combinatorial therapy with MFF for better clinical outcomes.

Octyl gallate has potent anti-inflammasome activity by directly binding to NLRP3 LRR domain.

The NOD-, LRR-, and Pyrin domain-containing protein 3 (NLRP3) inflammasome plays key roles in regulating inflammation. Numerous studies show that the abnormal activation of NLRP3 associates with the initiation and progression of various diseases. Hence, the NLRP3 inflammasome may be a promising therapeutic target for these diseases. Octyl gallate (OG) is a small molecule with antioxidant, antimicrobial, antifungal, and anti-inflammatory activities; however, the mechanism underlying its anti-inflammatory activity is still unclear. Here, we developed a screening system for NLRP3-inflammasome inhibitors. A total of 3287 small molecules were screened for inhibitors of nigericin-induced NLRP3 oligomerization. OG was identified as a novel inhibitor. We show that OG directly targets the LRR domain of NLRP3 and thereby blocks the inflammatory cascade of the NLRP3 inflammasome. This contrasts with the mode-of-action of other direct NLRP3 inhibitors, which all bind to the NACHT domain of NLRP3. Interestingly, OG also inhibits the priming step by downregulating the Raf-MEK1/2-ERK1/2 axis. Thus, OG inhibits the NLRP3 inflammasome by two distinct mechanisms. Importantly, OG injection ameliorated the inflammation in mouse models of foot gout and sepsis. Our study identifies OG as a potential therapeutic agent for NLRP3-associated diseases.

Effect of lipophilized gallic acid on the oxidative stability of omega-3 fatty acids rich soy and cow milk

The antioxidant and interfacial effects of gallate alkyl esters on the oxidative stability of fish oil-enriched cow milk (CM) and soymilk emulsions (SM) stored at 4 °C were evaluated. The peroxide value and volatile compounds were also measured to monitor the progress of lipid oxidation. Despite the higher amount of unsaturated fatty acids, the SM emulsion showed a considerable increase in the oxidative stability compared to CM emulsion. It was found that reducing chlorogenic acid content may contribute to the lipid oxidation of SM emulsions. Moreover, the results showed that the antioxidant efficiency of gallates had a positive correlation with their partitioning at the oil-water interface. Octyl gallate followed by propyl gallate with the same partition at the interface had the highest antioxidant effect in protecting SM and CM emulsions. In contrast, short and long-chain gallates showed a higher lipid oxidation due to the higher partitioning into the aqueous and oil phases.

Alkyl gallates inhibit serine O-acetyltransferase in bacteria and enhance susceptibility of drug-resistant Gram-negative bacteria to antibiotics.

A principal concept in developing antibacterial agents with selective toxicity is blocking metabolic pathways that are critical for bacterial growth but that mammalian cells lack. Serine O-acetyltransferase (CysE) is an enzyme in many bacteria that catalyzes the first step in l-cysteine biosynthesis by transferring an acetyl group from acetyl coenzyme A (acetyl-CoA) to l-serine to form O-acetylserine. Because mammalian cells lack this l-cysteine biosynthesis pathway, developing an inhibitor of CysE has been thought to be a way to establish a new class of antibacterial agents. Here, we demonstrated that alkyl gallates such as octyl gallate (OGA) could act as potent CysE inhibitors in vitro and in bacteria. Mass spectrometry analyses indicated that OGA treatment markedly reduced intrabacterial levels of l-cysteine and its metabolites including glutathione and glutathione persulfide in Escherichia coli to a level similar to that found in E. coli lacking the cysE gene. Consistent with the reduction of those antioxidant molecules in bacteria, E. coli became vulnerable to hydrogen peroxide-mediated bacterial killing in the presence of OGA. More important, OGA treatment intensified susceptibilities of metallo-β-lactamase-expressing Gram-negative bacteria (E. coli and Klebsiella pneumoniae) to carbapenem. Structural analyses showed that alkyl gallate bound to the binding site for acetyl-CoA that limits access of acetyl-CoA to the active site. Our data thus suggest that CysE inhibitors may be used to treat infectious diseases caused by drug-resistant Gram-negative bacteria not only via direct antibacterial activity but also by enhancing therapeutic potentials of existing antibiotics.

In vitro plasma hydrolysis of phenolic esters and their absorption kinetics in rats: Controlled release of phenolic compounds and enhanced health benefits

Phenolic esters are considered as promising functional food ingredients. However, their digestion, absorption and metabolism are still unclear. Tyrosol acyl esters (TYr-Es), hydroxytyrosol acyl esters (HTy-Es) and alkyl gallates (A-GAs) were hydrolyzed by carboxylesterase in plasma and exhibited slow release of polyphenols (phenolic acids). In vitro hydrolysis degrees initially increased and then decreased with the increasing carbon chain length (C2-C16). TYr-Es exhibited higher hydrolysis degrees compared to HTy-Es, and hydrolysis degrees of TYr-Es and HTy-Es were markedly higher than those of A-GAs. Due to the fast hydrolysis rates of TYr-Es and HTy-Es, they were undetectable in all rat plasma samples collected at several times within 24 h after administration. Whereas, A-GAs could be detected in rat plasmas and three absorption peaks were found in the pharmacokinetic profiles. Importantly, the T1/2, MRT, AUC0-∞, AUC0-t in octyl gallate group were longer (or stronger) than those in propyl gallate and dodecyl gallate groups.

New anti-α-Glucosidase and Antioxidant Ingredients from Winery Byproducts: Contribution of Alkyl Gallates.

Wine-making activity entails the production of solid and semisolid byproducts (grape stems and pomace and wine lees) that negatively impact the environment and industrial sustainability. Their features as sources of bioactive compounds support valorization procedures for functional and healthy ingredients. This work uncovers the quantitative alkyl gallates (gallic acid esters, C1-C12) profile of fresh (freeze-dried) materials and the effect of oven-drying on their stability by UHPLC-ESI-QqQ-MS/MS. The functionality was established concerning DPPH• scavenging and antihyperglycemic power. Wine lees exerted the highest high-free concentration of galloyl derivatives, ethyl gallate being the most abundant ester (3472.62 ng/g dw, on average). About the impact of the stabilization process, although as a general trend, the thermal treatment reduced the concentration, the reduction dimensions depended on the compound/matrix, remaining in valuable concentrations. Concerning radical scavenging, ze-dried stems and pomace displayed the highest capacity (24.11 and 18.46 mg TE/g dw, respectively), being correlated with propyl gallate (r2 = 0.690), butyl gallate (r2 = 0.686), and octyl gallate (r2 = 0.514). These two matrices exerted α-glucosidase inhibitory activity (1.58 and 1.46 units/L) equivalent to that of acarbose (a recognized α-glucosidase inhibitor). The newly described bioactive phytochemicals in winery residues (galloyl esters) and their correlation with functional traits allow for envisioning valorization alternatives.

Exploring the antioxidant “cut-off effect” of gallic acid alkyl esters in dried oysters (Crassostrea gigas) during storage

In some complex food matrices, lipophenols exert stronger antioxidant effects than free polyphenols due to their better amphiphilicity and solubility. The use of lipophenols of different chain lengths often presents a “cut-off effect” in real foods, but the reason is far from understood. This work compared the antioxidant capacity of ethyl gallate (EG), octyl gallate (OG) and myristyl gallate (MG) in dried oysters during storage. The oxidation rate of polyunsaturated fatty acids (PUFAs), oxidation inhibition rate of the antioxidants on PUFAs and the generation number of lipid hydroperoxides and aldehydes shown that the treatment of antioxidants effectively inhibited lipid oxidation during storage, and the inhibition ability in the OG group was significantly better than that in the other antioxidant groups, which was consistent with the as of the “cut-off effect”. The density functional theory (DFT) and the molecular dynamics (MD) simulation showed that this “cut-off effect” is related to the ability of the polyphenolic hydroxyl group at C4 to transfer hydrogen atoms and the effective concentration of lipophenols at the initiation site of lipid oxidation.

Ultraefficient OG-Mediated Photodynamic Inactivation Mechanism for Ablation of Bacteria and Biofilms in Water Augmented by Potassium Iodide under Blue Light Irradiation.

While photodynamic inactivation (PDI) has emerged as a novel sterilization strategy for drinking water treatment that recently attracted tremendous attention, its efficiency needs to be further improved. In this study, we aimed to clarify the ultraefficient mechanism by which potassium iodide (KI) potentiates octyl gallate (OG)-mediated PDI against bacteria and biofilms in water. When OG (0.15 mM) and bacteria were exposed to blue light (BL, 420 nm, 210 mW/cm2), complete sterilization (>7.5 Log cfu/mL of killing) was achieved by the addition of KI (250 mM) within only 5 min (63.9 J/cm2). In addition, at lower doses of OG (0.1 mM) with KI (100 mM), the biofilm was completely eradicated within 10 min (127.8 J/cm2). The KI-potentiated mechanism involves in situ rapid photogeneration of a multitude of reactive oxygen species, especially hydroxyl radicals (•OH), reactive iodine species, and new photocytocidal substances (quinone) by multiple photochemical pathways, which led to the destruction of cell membranes and membrane proteins, the cleavage of genomic DNA and extracellular DNA within biofilms, and the degradation of QS signaling molecules. This multitarget synergistic strategy provided new insights into the development of an environmentally friendly, safe, and ultraefficient photodynamic drinking water sterilization technology.

Natural phenolic compounds as biofilm inhibitors of multidrug-resistant Escherichia coli - the role of similar biological processes despite structural diversity.

Multidrug-resistant gram-negative pathogens such as Escherichia coli have become increasingly difficult to treat and therefore alternative treatment options are needed. Targeting virulence factors like biofilm formation could be one such option. Inhibition of biofilm-related structures like curli and cellulose formation in E. coli has been shown for different phenolic natural compounds like epigallocatechin gallate. This study demonstrates this effect for other structurally unrelated phenolics, namely octyl gallate, scutellarein and wedelolactone. To verify whether these structurally different compounds influence identical pathways of biofilm formation in E. coli a broad comparative RNA-sequencing approach was chosen with additional RT-qPCR to gain initial insights into the pathways affected at the transcriptomic level. Bioinformatical analysis of the RNA-Seq data was performed using DESeq2, BioCyc and KEGG Mapper. The comparative bioinformatics analysis on the pathways revealed that, irrespective of their structure, all compounds mainly influenced similar biological processes. These pathways included bacterial motility, chemotaxis, biofilm formation as well as metabolic processes like arginine biosynthesis and tricarboxylic acid cycle. Overall, this work provides the first insights into the potential mechanisms of action of novel phenolic biofilm inhibitors and highlights the complex regulatory processes of biofilm formation in E. coli.

New Palladium(II) Complexes Containing Methyl Gallate and Octyl Gallate: Effect against Mycobacterium tuberculosis and Campylobacter jejuni.

This work describes the preparation, characterization and antimicrobial activity of four palladium(II) complexes, namely, [Pd(meg)(1,10-phen)] 1, [Pd(meg)(PPh3)2] 2, [Pd(og)(1,10-phen)] 3 and [Pd(og)(PPh3)2] 4, where meg = methyl gallate, og = octyl gallate, 1,10-phen = 1,10-phenanthroline and PPh3 = triphenylphosphine. As to the chemical structures, spectral and physicochemical studies of 1-4 indicated that methyl or octyl gallate coordinates a palladium(II) ion through two oxygen atoms upon deprotonation. A chelating bidentate phenanthroline or two triphenylphosphine molecules complete the coordination sphere of palladium(II) ion, depending on the complex. The metal complexes were tested against the Mycobacterium tuberculosis H37Rv strain and 2 exhibited high activity (MIC = 3.28 μg/mL). As to the tests with Campylobacter jejuni, complex 1 showed a significant effect in reducing bacterial population (greater than 7 log CFU) in planktonic forms, as well as in the biomass intensity (IBF: 0.87) when compared to peracetic acid (IBF: 1.11) at a concentration of 400 μg/mL. The effect provided by these complexes has specificity according to the target microorganism and represent a promising alternative for the control of microorganisms of public health importance.