Octyl gallate, a food additive with potential beneficial properties to treat Helicobacter pylori infection

Abstract

Helicobacter pylori infection is marked by intense production of reactive oxygen species (ROS) through the activation of neutrophils that are constantly attracted to the infected gastric mucosa. Here, gallic acid and its alkyl esters were evaluated as compounds able to act as antimicrobial agents and inhibitors of ROS released by H. pylori-activated neutrophils simultaneously. We found that the higher hydrophobicity caused by esterification of gallic acid led to a significant increase in its ability as a cytotoxic agent against H. pylori, a scavenger of ROS and an inhibitor of NADPH oxidase in neutrophils. Octyl gallate, a widely used food additive, showed the highest antimicrobial activity against H. pylori, with a minimum inhibitory concentration (MIC) value of 125 μg mL, whereas gallic acid had a MIC value higher than 1000 μg mL. The production of superoxide anion radicals was almost 100% abolished by the addition of 10 μM (2.82 μg mL) octyl gallate, whereas gallic acid inhibited around 20%. A similar tendency was also found when measuring the production of hypochlorous acid. The protective effect of the esters was cytochemically confirmed. In conclusion, this study showed that hydrophobicity is a crucial factor to obtain a significant anti-ROS and anti-H. pylori activity. Finally, it highlights octyl gallate, a food additive widely used in the food industry, as a promising molecule in the treatment of H. pylori infection.

Entropy‐driven binding of octyl gallate in albumin: Failure in the application of temperature effect to distinguish dynamic and static fluorescence quenching

“…This property has been explored in its antitumor effect on B‐cell leukemia, melanoma, and lymphoma . G8 also features antibacterial, antifungal, antiviral, antidiabetic, antiamyloidogenic, and anticancer activities . In the present study, G0 and G8 were chosen to study the relevance of ligand hydrophilicity on binding affinity with albumin.…”

Development of a caffeic acid–phthalimide hybrid compound for NADPH oxidase inhibition

“…Our last publications have argued that a unifying characteristic of the phenolic acid derivatives that presented inhibitory effect was their increased hydrophobicity. 57,58,72,86 We propose that these redox-active lipophilic molecules could more easily access NADPH oxidases as a membrane protein. This property is also present in the hybrid molecule developed here.…”

“…In the last years, we have shown the efficacy of some phenolic acid derivatives as inhibitors of NOX2 and called the attention of readers for a real inhibition and not only scavenger effects. 57,58,72,86 Here, we advanced in this proposal by developing the hybrid caffeic acid-phthalimide compound. As we have demonstrated, the hybrid compound's redox properties were not improved compared to caffeic acid, a widely recognized and potent ROS scavenger; 60 actually, a slight decrease was observed.…”

“…1) was based on the previously described pharmacological properties of its precursors [33][34][35][36][37][38][39][54][55][56] and the benecial effect of an increased hydrophobicity for an NADPH oxidase inhibitor. 40,57,58 C2 was synthesised through a one-step reaction between caffeic acid (C1) and N-(3-bromopropyl)phthalimide, two commercial and relatively inexpensive chemicals. The higher hydrophobicity index of C2 (log P ¼ 2.27) was obtained by the ester moiety and the aliphatic three-carbon chain linkage between C1 (log P ¼ 1.15) and the phthalimide nucleus.…”

Anti‐inflammatory effect of octyl gallate in alveolar macrophages cells and mice with acute lung injury

“…We used the octyl gallate (OG) compound, an ester derived from gallic acid. OG is a phenolic compound with therapeutic actions namely antimicrobial, antiviral, and antifungal (Hsu, Chang, & Chang, 2007; Kubo, Xiao, & Fujita, 2001; Latha & Daisy, 2013; Uozaki et al, 2007; Wolf, Bonacorsi, Raddi, da Fonseca, & Ximenes, 2017). In this study, we evaluated it action on LPS‐induced alveolar macrophages RAW 264.7 and ALI in male mice.…”