Neutrophils are key cells of the innate immune and inflammatory responses. They are the first blood cells to migrate to the infection site where they release high amounts of reactive oxygen species (ROS) and several peptides and enzymes required for microbial killing. However, excessive neutrophil activation can induce tissue injury participating in inflammation, thus the characterization of the enzymes involved in neutrophil activation could help to identify new pharmacological targets to treat inflammation. The prolyl-isomerase Pin1 is a ubiquitous enzyme involved in several functions, however, its role in neutrophil functions is less known. In this study, we show that the bacterial peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP or fMLF), a G-protein coupled receptor (GPCR) agonist-induced Pin1 activation in human neutrophils. PiB and juglone, two Pin1 inhibitors inhibited Pin1 activity in neutrophils and consequently inhibited fMLP-induced chemotaxis and -degranulation of azurophil and specific granules as measured by myeloperoxidase and neutrophil gelatinase-associated lipocalin (NGAL) release respectively. We also showed that PiB inhibited TNFα + fMLP-induced superoxide production, confirming the effect of juglone. These data show that inhibitors of Pin1 impaired key pro-inflammatory neutrophil functions elicited by GPCR activation and suggest that Pin1 could control neutrophil inflammatory functions.

Garlic (Allium sativum) is recognized as functional food, rich in bioactive compounds that can combat diseases associated with oxidative stress. This study aims to investigate the protective potential of aqueous garlic extract against hemolysis and oxidation. Despite being caused by membrane fragility, hemolysis can lead to inflammation through the oxidation of its products, and in some cases, even exacerbate it in certain pathological contexts. Supplementation with antioxidant molecules can improves oxidative status, in this study, we selected garlic, an excellent functional food, and targeted its effects using aqueous extract and pure molecules. The aqueous garlic extract was prepared under safe conditions and subjected to toxicity on human neutrophils and red blood cells before experimentation. The results indicate that aqueous garlic extract significantly reduces hemolysis with a maximum protection of 98. 74 ± 1. 08 % at a concentration of 5μg/ml. Additionally, experiments were conducted with pure compounds found in garlic such as quercetin, gallic acid, and caffeic acid. The outcomes show that quercetin reduces hemolysis of RBC with a maximum protection of 88. 8 ± 2. 89 % at 20 µM followed by caffeic acid and gallic acid. The action mechanism of the extract was tested on human neutrophil cells, the extract significantly reduced luminol-amplified chemiluminescence of PMA-stimulated neutrophils up to 50 % at 10 µg/ml in addition to its ability to directly scavenge hydrogen peroxide. Our results suggest that aqueous garlic extract exerts promising anti-inflammatory activity in vitro. Through its dual protection against hemolysis and Ros production, garlic may indirectly prevent inflammation reducing the oxidation of hemolysis products. These abilities make garlic aqueous extract promising candidate for improving cardiovascular health, reducing oxidative stress and modulating immunity.

Biofilms represent complex three-dimensional microbial communities that can harbor strains highly resistant to antimicrobial agents. These structures, which form on both biotic and abiotic surfaces, are associated with food spoilage and increased complications in hospitalized patients. Consequently, there is significant interest in developing novel biofilm and infection control strategies, particularly those focusing on natural molecules with dual antimicrobial and antibiofilm properties. In this study, olive tree twigs from three varieties of Olea europea chemlal (CH), Azeradj (AZ), and wild-type Olea europaea sylvestris (W) were collected from the Kabylia region in Algeria. The samples underwent systematic extraction and were evaluated for their antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, antimicrobial properties via disk diffusion assay, minimum inhibitory concentration (MIC), and antibiofilm capabilities. Results demonstrated that olive tree twig extracts exhibited substantial antioxidant activity and significant antibacterial and antibiofilm potential. The antioxidant activity, measured through DPPH radical scavenging, showed IC50 values ranging from 38.12 ± 1.52 µg/mL to 148.7 ± 1.23 µg/mL. When tested against six pathogenic bacterial strains, including both ATCC reference strains and milk isolates, the MIC values ranged from 1.18 mg/mL to 4.71 mg/mL. Notably, sub-inhibitory concentrations significantly reduced biofilm formation across most tested strains, with inhibition rates varying from 21% to 90.43%. The effectiveness of biofilm inhibition was dependent on the bacterial strain, olive tree variety, and extract concentration used. Statistical analysis confirmed the significance of these results (p < 0.05). Given the demonstrated antioxidant, antibacterial, and antibiofilm properties of these olive tree twig extracts, they show promise for further development as surface disinfectants and potential applications in food safety and infection control. Additional research is warranted to fully characterize their mechanisms of action and optimize their practical applications.

Orange peel aqueous extract and its major compound hesperidin inhibit neutrophil oxidative burst, MPO release, and chemotaxis, reducing inflammation in a rat pleurisy model.