Search Results (111)

Cardiac glycosides (CGs), a class of plant- and animal-derived compounds historically used to treat heart failure, have garnered renewed interest for their diverse pharmacological properties beyond Na⁺/K⁺-ATPase (NKA) inhibition. Recent studies reveal that CGs modulate key signaling pathways—such as NF-κB, PI3K/Akt, JAK/STAT, and MAPK—affecting processes central to cancer, viral infections, immune regulation, and neurodegeneration. In cancer, CGs induce multiple forms of regulated cell death, including apoptosis, ferroptosis, pyroptosis, and immunogenic cell death, while also inhibiting angiogenesis, epithelial–mesenchymal transition, and cell cycle progression. They demonstrate broad-spectrum antiviral activity by disrupting viral entry, replication, and mRNA processing in viruses such as HSV, HIV, influenza, and SARS-CoV-2. Immunologically, CGs regulate Th17 differentiation via RORγ signaling, although both inhibitory and agonistic effects have been reported. In the nervous system, CGs modulate neuroinflammation, support synaptic plasticity, and improve cognitive function in models of Alzheimer’s disease, epilepsy, and multiple sclerosis. Despite their therapeutic potential, clinical translation is hindered by narrow therapeutic indices and systemic toxicity. Advances in drug design and nanocarrier-based delivery are critical to unlocking CGs’ full potential as multi-target agents for complex diseases. This review synthesizes the current knowledge on the emerging roles of CGs and highlights strategies for their safe and effective repurposing. Full article

Under the principles of the circular economy and sustainability, consumers, the food industry and health authorities have interest in new natural food preservatives to prevent foodborne diseases and increase produce shelf life. This work aimed to evaluate the antimicrobial properties of cowpea plant extracts. Grain, pod and leaf extracts from five Portuguese cowpea accessions were characterized in terms of their phenolic content. The values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined against pathogenic and non-pathogenic bacteria, as well as on post-harvest pathogenic filamentous fungi. In general, the phenolic content of pod extracts was higher than that of grains and leaves, although leaf extracts had the highest content of a broad-spectrum antibacterial flavonoid, quercetin. Grain extracts exhibited no detectable antimicrobial activity. In contrast, leaf and pod extracts from all five accessions generally displayed bactericidal effects. For bacteria, pod extracts showed MICs ranging from 5.1 to 87.7 mg/mL and MBCs from 20.3 to 87.7 mg/mL. Leaf extracts showed the most promising results, with MICs and MBCs ranging from 1.1 to 9.1 mg/mL. The results against fungi were not so expressive; nevertheless, P. expansum was inhibited by 9 L leaf extract even if at a higher concentration (MIC = 18 mg/mL) than those obtained for bacteria. The Portuguese variety Fradel (1E) showed very promising antibacterial activity, with leaf extracts showing low MBC values (from 2.3 to 9.1 mg/mL). The obtained results indicate that cowpea pods and leaves have antimicrobial properties and could potentially be used as a source of compounds for food preservation. Full article

Probiotics exert beneficial effects on health improvement, infection prevention, and disease management. This study investigated the probiotic characteristics and safety parameters of Levilactobacillus brevis ZG2488, a novel strain isolated from healthy human feces. The strain exhibited robust tolerance to simulated gastrointestinal conditions, maintaining survival rates of 87.20% in artificial gastric juice (pH 3.0; 3 h) and 95.32% in 0.3% bile salt (24 h). Notably, L. brevis ZG2488 displayed superior microbial adhesion properties with high cell surface hydrophobicity (87.32%), auto-aggregation (81.15% at 24 h), and co-aggregation capacities with Escherichia coli ATCC 43895 (63.90%) and Salmonella typhimurium SL1344 (59.28%). Its adhesion to HT-29 cells (7.15%) surpassed that of the reference strain Lactobacillus rhamnosus GG (1.26%). Antimicrobial testing revealed broad-spectrum inhibitory effects against multidrug-resistant Klebsiella pneumoniae NK04152 and other pathogens. Comprehensive safety assessments confirmed the absence of hemolytic or DNase activity, along with appropriate antibiotic susceptibility to most antibiotics, except kanamycin, streptomycin, vancomycin, and penicillin G. Furthermore, L. brevis ZG2488 significantly enhanced nitric oxide production and upregulated the gene expression of nitric oxide synthase (iNOS) and proinflammatory cytokines (IL-1β, IL-6, and TNF-α) in RAW264.7 macrophages. These findings underscore L. brevis ZG2488 as a promising probiotic candidate with functionality in pathogen inhibition and immune modulation. Full article

The global rise in antimicrobial resistance, particularly among ESKAPE pathogens, has intensified the demand for alternative therapeutic strategies. Silver nanoparticles (AgNPs) have exhibited broad-spectrum antimicrobial activity and represent a promising approach to combat multidrug-resistant infections. This study aimed to synthesize and functionalize AgNPs using various polymeric agents—ethylene glycol (EG), polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), and their combinations—and to evaluate their antimicrobial and antibiofilm efficacy against clinically relevant bacterial strains. AgNPs were synthesized via chemical reduction and functionalized as Ag@EG, Ag@PEG, Ag@EG/PVP, and Ag@PEG/PVP. A total of 68 clinical isolates—including Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus lugdunensis, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa—were tested. Antimicrobial susceptibility was assessed using disc diffusion and broth microdilution assays, while antibiofilm activity was evaluated via the crystal violet method. Among all tested formulations, Ag@EG/PVP exhibited the highest antimicrobial and antibiofilm activity, with notably low minimum inhibitory concentrations (MIC₅₀) and minimum biofilm eradication concentrations (MBEC₅₀) for Ps. aeruginosa and K. pneumoniae. In contrast, AgNPs functionalized with PEG or EG alone showed limited efficacy. Biofilm-forming isolates, particularly Staphylococcus spp., required higher concentrations for inhibition. These results highlight the critical role of functionalization in modulating the antimicrobial properties of AgNPs, with Ag@EG/PVP demonstrating potent activity against both planktonic and biofilm-associated multidrug-resistant bacteria. Overall, this study supports further developing AgNPs-based formulations as adjuncts or alternatives to conventional antibiotics, particularly for managing biofilm-related infections. Future research should focus on formulation optimization, safety assessment, and translational potential. Full article

Bacterial diseases cause high mortality and considerable losses in aquaculture. The rapid expansion of intensive aquaculture has further increased the risk of large-scale outbreaks. However, the emergence of drug-resistant bacteria, food safety concerns, and environmental regulations have severely limited the availability of antimicrobial. Compared to traditional antibiotics, antimicrobial peptides (AMPs) offer broad spectrum activity, physicochemical stability, and lower resistance development. However, their low natural yield and high extraction costs along with the time-consuming and expensive nature of traditional drug discovery, pose a challenge. In this study, we applied a machine-learning macro-model to predict AMPs from three macrogenomes in the water column of South American white shrimp aquaculture ponds. The AMP content per megabase in the traditional earthen pond (TC1) was 1.8 times higher than in the biofloc pond (ZA1) and 63% higher than in the elevated pond (ZP11). A total of 1033 potential AMPs were predicted, including 6 anionic linear peptides, 616 cationic linear peptides, and 411 cationic cysteine-containing peptides. After screening based on structural, and physio-chemical properties, we selected 10 candidate peptides. Using a rapid high-throughput cell-free protein expression system, we identified nine peptides with antimicrobial activity against aquatic pathogens. Three were further validated through chemical synthesis. The three antimicrobial peptides (K-5, K-58, K-61) showed some inhibitory effects on all four pathogenic bacteria. The MIC of K-5 against Vibrio alginolyticus was 25 μM, the cell viability of the three peptides was higher than 70% at low concentrations (≤12.5 μM), and the hemolysis rate of K-5 and K-58 was lower than 5% at 200 μM. This study highlights the benefits of machine learning in AMP discovery, demonstrates the potential of cell-free protein synthesis systems for peptide screening, and provides an efficient method for high-throughput AMP identification for aquatic applications. Full article

The 20S proteasome, a critical component of the ubiquitin–proteasome system, plays a central role in regulating protein degradation in eukaryotic cells. Marizomib (MZB), also known as salinosporamide A, is a natural γ-lactam-β-lactone compound derived from Salinispora tropica and is a potent 20S proteasome covalent inhibitor with demonstrated anticancer properties. Its broad-spectrum inhibition of all three proteasome subunits and its ability to cross the blood–brain barrier has made it a promising therapeutic candidate for glioblastoma. In addition to this, MZB also demonstrates significant inhibition against the 20S proteasome of Trichomonas vaginalis (Tv20S), a protozoan parasite, suggesting its potential for parasitic treatments. Here, we present the cryo-EM structure of the human 20S proteasome in complex with MZB at 2.55 Å resolution. This structure reveals the binding mode of MZB to all six catalytic subunits within the two β-rings of the 20S proteasome, providing a detailed molecular understanding of its irreversible inhibitory mechanism. These findings enhance the therapeutic potential of MZB for both cancer and parasitic diseases at the molecular level and highlight marine-derived natural products in targeting the proteasome for therapeutic applications. Full article

This study explores the potential of silver nanoparticles (AgNPs) synthesized through an eco-friendly method using coffee extract to combat non-bacterial mastitis in dairy cattle. Mastitis, often caused by pathogens such as yeasts and algae like Prototheca spp., poses a challenge due to the limited efficacy of traditional antibiotics. This research utilized strains isolated from mastitis milk and assessed the nanoparticles’ physicochemical properties, antimicrobial efficacy, and impact on biofilm formation and microorganism invasion. AgNPs demonstrated a spherical shape with a mean hydrodynamic diameter of ~87 nm and moderate colloidal stability. Antimicrobial tests revealed significant growth inhibition of yeast and Prototheca spp., with minimal inhibitory concentrations (MICs) as low as 10 mg/L for certain strains. Biofilm formation was notably disrupted, and microorganism invasion in bioprinted gels was significantly reduced, indicating the broad-spectrum potential of AgNPs. The study highlights the nanoparticles’ ability to damage cell membranes and inhibit metabolic activities, presenting a promising alternative for managing infections resistant to conventional treatments. These findings suggest that green-synthesized AgNPs could play a pivotal role in developing sustainable solutions for mastitis treatment, particularly for pathogens with limited treatment options. Full article

Antimicrobial resistance is a growing global challenge, rendering many standard treatments ineffective. Essential oils (EOs) of cinnamon (Cinnamomum aromaticum Nees) and clove (Syzygium aromaticum (L.) Merr. et Perry) may offer an alternative solution due to their high antimicrobial properties and their abilities to fight resistant pathogens. This study evaluates the antimicrobial activity of these two EOs, and their synergistic potential when combined with two antibiotics (ciprofloxacin and vancomycin) and two antifungals (fluconazole and amphotericin B) against various bacterial and yeasts strains. The antimicrobial activities of each EO were evaluated by agar diffusion and broth microdilution assays, while the synergetic effects with antimicrobials were determined by calculating the fractional inhibitory concentration index (FICI) using the checkerboard method. The chemical composition of the EOs was analyzed using Gas Chromatography-Mass Spectrometry (GC-MS). The identification of individual components in the EOs was achieved by comparing their mass spectra with the NIST MS Search database and by correlating their retention times with those of known standards. GC-MS analysis revealed that the main constituents of S. aromaticum EO were eugenol (71.49%) and β-caryophyllene (23.43%), while C. aromaticum EO were dominated by cinnamaldehyde (47,04%) and cinnamyl acetate (18.93%). Antimicrobial activity showed that cinnamon EO exhibits highest effectiveness against all tested strains, with inhibition zones (IZ) ranging from 16.99 mm to 53.16 mm, and minimum inhibitory concentrations (MIC) and minimum microbicidal concentrations (MMC) ranging from 0.039 mg/mL to 0.156 mg/mL. However, for clove EO, the IZ ranged from 9.31 mm to 29.91 mm, with MIC and MMC values from 0.313 mg/mL to 1.25 mg/mL. In combination with antibiotics (ciprofloxacin and vancomycin), the studied EOs showed promising synergistic effects with reduction up to 128-fold. As regards antifungals (amphotericin B, and fluconazole), the synergistic effects were recorded with MIC gains up to 32-fold. Our findings demonstrate that the EOs from C. aromaticum and S. aromaticum exhibit significant broad-spectrum antimicrobial activity against diverse yeast and bacterial strains. This highlights their potential as bases for the development of novel plant-based antimicrobial agents. Importantly, the observed synergistic effects of these EOs with conventional antibiotics support their integration into medical treatments as a strategy to address microbial resistance. Future research should aim to elucidate the mechanisms underlying these synergistic actions, optimize their application, and enhance their therapeutic efficacy. Full article

The aim of this study was to identify and characterize the bioactive peptide profile of Podolica cow’s milk. This dairy product is known for its nutritional properties related to the presence of peculiar lipids and is a typical breed traditionally reared in southern Italy. Using top-down peptidomics, we identified 2213 peptides in milk samples from four different farms, with 19 matching bioactive sequences. Bioactivities include dipeptidyl peptidase-IV (DPP-IV) inhibition, angiotensin-converting enzyme (ACE) inhibition, antioxidant activity, enhanced calcium uptake, and other peptides with potential antimicrobial effects. DPP-IV-inhibitory peptides (e.g., LDQWLCEKL and VGINYWLAHK) suggest potential for type 2 diabetes management, while ACE inhibitors (such as YLGY and FFVAPFPEVFGK) could support cardiovascular health by reducing hypertension. Antimicrobial peptides such as SDIPNPIGSENSEK and VLNENLLR showed broad spectrum of activity against various harmful microorganisms, positioning Podolica milk as a promising source for natural antimicrobial agents. Additionally, peptides with osteoanabolic, antianxiety, and immunomodulatory properties further highlight the multifaceted health benefits associated with this type of milk. Our findings underline the functional richness of Podolica milk peptides with various bioactivity properties, which could enhance the value of derived dairy products and contribute to sustainable agricultural practices. Future research will aim to explore these bioactivity properties in vivo, establishing a foundation for functional foods and supplements based on Podolica milk. Full article

6-Aryl-2-picolinic acid herbicides are an important subclass of auxin herbicides, characterized by their good absorption and conductivity, broad weed control spectrum, and excellent herbicidal activity against some resistant weeds. Based on previous studies from our group and the distinct characteristics of physico-chemical properties and biological activities of active skeleton structure containing fluorine atoms, this paper introduces the design and synthesis of 41 novel 4-amino-6-(5-aryl-substituted-1-pyrazolyl)-3-chloro-5-fluoro-2-picolinic acid compounds. The test of inhibiting A. thaliana roots growth showed that most of the S-series compounds exhibited superior inhibitory effects compared to picloram, with six compounds demonstrated even better inhibitory capability than the new herbicidal molecule florpyrauxifen. For example, compound S202, at a concentration of 0.5 µmol/L, exhibited a 78.4% inhibition of A. thaliana root growth, whereas florpyrauxifen showed only a 33.8% inhibition. Root growth inhibition tests on weeds showed that 28 compounds, at a concentration of 250 µM, demonstrated a greater than 80% inhibition of Brassica napus (BN) root growth. Post-emergence herbicidal activity tests showed that most compounds exhibited good inhibitory effects on broadleaf weeds, with 10 compounds achieving a 100% inhibition of the growth of Amaranthus retroflexus L (AL). These results demonstrate that some of the 4-amino-6-(5-aryl-substituted-1-pyrazolyl)-3-chloro-5-fluoro-2-picolinic acid compounds could be used as potential lead structures in the discovery of novel synthetic auxin herbicides. Full article

Melittin, a naturally occurring antimicrobial peptide, demonstrates broad-spectrum activity, effectively suppressing and eliminating both Gram-positive and Gram-negative bacteria, including specific drug-resistant strains. In this study, molecular simulation software was employed to investigate and modify the structure of melittin with the aim of synthesizing a modified peptide exhibiting enhanced antibacterial potency and assessing its bacteriostatic and antibacterial properties. The primary research objectives were as follows: 1. Preparation and characterization of melittin-modified peptide—Using molecular simulation software, the structure of the melittin-modified peptide was adjusted to predict its activity and select the most appropriate amino acid sequence. The peptide was synthesized through solid-phase peptide synthesis employing the Fmoc strategy and subsequently purified using liquid chromatography. The yield of the purified modified melittin was determined to be 30.97%, and the identity of the product was confirmed by LC-MS and MALDI-TOF-MS. 2. Evaluation of the antimicrobial activity of the melittin-modified peptide—The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of melittin and its modified peptide were measured using gradient dilution and plate counting techniques. The results revealed that both melittin and its modified peptide exhibited strong antibacterial efficacy against Gram-positive and Gram-negative bacteria, as well as certain drug-resistant strains. This showed that melittin and its modified peptide have the same antibacterial (killing) effect. A scanning electron microscope analysis indicated that both melittin and its modified peptide were capable of disrupting bacterial cell structures, leading to bacterial cell death. Full article

Microbial resistance to conventional biocides is closely linked to the more complex problem of antibiotic resistance. Therefore, the development of novel and highly antimicrobial effective disinfectants is encouraged. Due to their broad spectrum of action and low toxicity, Argirium Silver Ultra Nano Clusters (Argirium SUNc^®), a new generation of silver nanoparticles, could be one of them. In this regard, the aim of the present work was to evaluate their biocidal properties in two different formulations against the hygiene indicator microorganisms potentially present in three different Italian food industries and to compare them with the chemical disinfectant most commonly used by operators for routine cleaning. Therefore, a series of microbiological swabs on different foodstuff contact surfaces were performed before and after the application of the solutions at each food company. The data showed that this novel nanomaterial was effective against all the parameters analyzed, being able to inhibit or reduce the growth of the tested microorganisms. Furthermore, in most cases, the two sanitizing solutions tested had a greater inhibitory power than the conventional disinfectant. For this reason, Argirium SUNc^® has great potential to be used in the near future as a new-generation disinfectant, an alternative to conventional disinfectants that promote the spread of antibiotic resistance. Full article

Aeromonas species are among the main pathogens causing rainbow trout infections. Silver nanoparticles (AgNPs) have a broad spectrum of antimicrobial properties and are usually produced by various green-synthesis methods. However, the application of commercialized AgNPs has not fully been clarified. Thus, the objective of this study was to evaluate the antibacterial activities of commercialized AgNPs (range of sizes 10–12 nm) on two contrasting A. salmonicida strains (I-1 and I-4), isolated from rainbow trout; the antibacterial mechanism, histopathological alterations and the expression of immune-related genes were investigated. In vitro, the minimal inhibitory concentration (MIC) was 10 µg/mL for I-1, and lowered to 9.5 µg/mL for I-4, respectively. AgNPs were shown to disrupt both the cell wall and membrane of I-1 and I-4, resulting in cell lysis and degradation. In vivo, rainbow trout challenged by immersed or intraperitoneally injected infection, the 10 µg/mL AgNP-treated groups, both showed delayed deaths and lower mortalities compared to the control groups, without any clinical signs and pathological changes. Especially for the virulent I-4, the enhanced expressions of immune-related genes TNF-α, IL-1β, IL-10 and IL-11 were significantly reduced in the AgNP-treated group, indicating a lesser inflammation due to the application of AgNPs. This study would lay theoretical foundation for the wide application of silver nanoparticles in fish diseases. Full article

The overprescription of antibiotics in medicine and agriculture has accelerated the development and spread of antibiotic resistance in bacteria, which severely limits the arsenal available to clinicians for treating bacterial infections. This work discovered a new class of heteroarylcyanovinyl quinazolones and quinazolone pyridiniums to surmount the increasingly severe bacterial resistance. Bioactive assays manifested that the highly active compound 19a exhibited strong inhibition against MRSA and Escherichia coli with extremely low MICs of 0.5 μg/mL, being eightfold more active than that of norfloxacin (MICs = 4 μg/mL). The highly active 19a with rapid bactericidal properties displayed imperceptible resistance development trends, negligible hemolytic toxicity, and effective biofilm inhibitory effects. Preliminary explorations on antibacterial mechanisms revealed that compound 19a could cause membrane damage, embed in intracellular DNA to hinder bacterial DNA replication, and induce metabolic dysfunction. Surprisingly, active 19a was found to trigger the conformational change in PBP2a of MRSA to open the active site, which might account for its high inhibition against MRSA. In addition, the little effect of molecule 19a on the production of reactive oxygen species indicated that bacterial death was not caused by oxidative stress. The above comprehensive analyses highlighted the large potential of quinazolone pyridiniums as multitargeting broad-spectrum antibacterial agents. Full article

Cationic gemini surfactants are used due to their broad spectrum of activity, especially surface, anticorrosive and antimicrobial properties. Mixtures of cationic and anionic surfactants are also increasingly described. In order to investigate the effect of anionic additive on antimicrobial activity, experimental studies were carried out to obtain MIC (minimal inhibitory concentration) against E. coli and S. aureus bacteria. Two gemini surfactants (12-6-12 and 12-O-12) and two single quaternary ammonium salts (DTAB and DDAC) were analyzed. The most commonly used commercial compounds of this class, i.e., SDS and SL, were used as anionic additives. In addition, computer quantum mechanical studies were also carried out to confirm the relationship between the structure of the mixture and the activity. The obtained results of microbiological tests and quantum mechanical calculations are in agreement with each other and show the lack of synergism in catanionic mixtures in the case of antibacterial activity. Full article