Search Results (10,580)

Background/Objectives: The global rise in multidrug-resistant (MDR) bacteria, particularly methicillin-resistant and methicillin-susceptible Staphylococcus aureus (MRSA and MSSA), continues to pose a major public health challenge, including in Hawaii. This underscores the need to discover new antimicrobial agents from natural sources. Guided by teachings from a Buddhist master regarding the medicinal value of lichens, we investigated the endemic Hawaiian lichen Cladonia skottsbergii. Methods: Specimens of C. skottsbergii were collected from the Lotus Buddhist Monastery in Mountain View, Hawaii. A methanolic extract was prepared and purified using chromatographic techniques, and compound structures were elucidated through spectroscopic analyses and single-crystal X-ray diffraction. The antibacterial activity of the compounds was assessed against Gram-positive strains (MRSA, MSSA) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa). Cytotoxicity was assessed using A549 (non-small cell lung cancer) and Vero E6 (non-tumorigenic) cell lines. Results: Three compounds were isolated: clarosione (1), a newly identified trichlorinated xanthone, and two known metabolites, (S)-usnic acid (2) and perlatolic acid (3). Compounds 2 and 3 demonstrated strong inhibitory effects against MRSA and MSSA. Their minimum inhibitory concentrations (MICs) ranged from 2 to 4 µg/mL, compared with vancomycin (0.5–1 µg/mL). Cytotoxicity testing showed higher sensitivity in A549 cells than in Vero E6 cells, resulting in favorable selectivity indices for the active compounds. Conclusions: In the current study, a new compound, clarosione (1) was discovered. This enhances our understanding of the constituents of C. skottsbergii and its potential antibacterial properties. Lichen-derived compounds may serve as lead candidates for further development, and further study is warranted. Full article

The shift toward sustainable packaging requires biodegradable, active alternatives. This study developed ternary nanohybrids by loading carvacrol (CV) or trans-cinnamaldehyde (tCN) onto zinc oxide/natural zeolite (ZnO/NZ) hybrids, which were incorporated into a poly-L-lactide/tri-ethyl citrate (PLA/TEC) matrix via melt extrusion to produce active films. A key finding was the distinct interaction mechanism: tCN underwent strong chemisorption with ZnO, creating a sustained-release reservoir, while CV was predominantly physisorbed, leading to rapid release. This interfacial divergence dictated functional performance. Antibacterial assessment of nanohybrids revealed that tCN@ZnO/NZ0.25 exhibited the highest inhibition zones against pathogens, correlating with its chemisorbed reservoir. In films, however, CV-based formulations (especially CV@ZnO/NZ0.25) showed superior immediate antioxidant activity (EC₅₀, ~DPPH~ = 34.43 mg/mL) and an 82% reduction in oxygen permeability. In contrast, tCN-based films (especially tCN@ZnO/NZ1.0) demonstrated superior, sustained antibacterial efficacy. In a minced pork preservation study, both films delayed lipid oxidation and preserved heme iron, while the tCN-based film provided better long-term microbial control. This work demonstrates that engineering the nanocarrier–active compound interface enables precise tailoring of release kinetics, which can be optimized for either high immediate antioxidant power or long-term antimicrobial action, depending on specific food preservation requirements. Full article

Thymus, Satureja, and Monarda are three plant genera, belonging to the Lamiaceae family, that are particularly valued for their essential oils (EOs) abundant in phenolic terpenoids. In this study, a botanical characterization of the following eight Eastern European cultivars (some of them newly bred) grown in Ukraine is distinguished: Thymus vulgaris (‘Yalos’, ‘101’), Thymus richardii (‘Fantasia’), Satureja montana (‘Krymsky smaragd’, ‘Lunata’, ‘4-18’), Monarda fistulosa (‘Premiera’), and Monarda × hybrida hort., which is a Monarda didyma × Monarda fistulosa hybrid (‘Tonya’). The EO of those cultivars was obtained and characterized in detail using GC-MS and GC-FID. Additionally, some biological activities of these oils were tested. Antimicrobial activity was verified against Escherichia coli, Staphylococcus aureus, and Candida albicans using disk diffusion and microdilution methods. Furthermore, some preliminary tests were performed on the motility of bull sperm using the CASA system. All the Thymus cultivars were very rich in thymol (57.99–67.62%), and all the S. montana cultivars were very abundant in carvacrol (62.22–75.53%). M. fistulosa cv. ‘Premiera’ contained mainly thymol (49.87%), and M. × hybrida cv. ‘Tonya’ contained both thymol (46.70%) and carvacrol (10.37%). All the tested EOs, as well as thymol and carvacrol, exhibited strong antibacterial and antifungal action with minimal inhibitory concentrations ranging from <0.25–0.5 mg/mL for Satureja, through <0.25–0.5 mg/mL for Monarda, to 0.5–4 mg/mL for Thymus. The EOs, at a concentration of 0.4 µL/mL, exhibited cytotoxicity towards bull spermatozoa when compared to the control sample. Full article

Recent studies have shown that wood tar exhibits excellent potential as an additive to polymers for food packaging. In this study, we demonstrated that the differential temperature of dry pyrolysis of wood affects the antioxidant and antibacterial activities of the liquid pyrolysis products (LPP). Birch LPP showed, on average, approximately 16% higher reducing power in the ferric-reducing antioxidant power (FRAP) assay and, on average, approximately 29% lower free radical scavenging activity than pine LPP. Thermal characterization suggests a qualitatively similar chemical composition among the tested fractions, with the 500 °C pyrolysis fraction showing the highest thermal resistance (lowest mass loss). Thermal characterization indicated similarities in the qualitative chemical composition of the tested fractions. Analyzed products demonstrated bactericidal activity against human- or plant-pathogenic bacteria and exhibited poor antimicrobial activity towards probiotic bacteria. Specifically, Lactoplantibacillus sp. and L. rhamnosus were, on average, approximately 61% and 45% less affected, respectively, compared to the most sensitive E. coli. We demonstrate apparent, predominantly substrate-driven differences in antibacterial activity, with Gram-negative bacteria being more susceptible to pine products and Gram-positive bacteria being more susceptible to birch products. Full article

Antimicrobial resistance (AMR) is a major global health concern, which complicates treatment of microbial infections and wounds. Conventional therapies are no longer effective against drug resistant microbes; hence, novel antimicrobial approaches are urgently required. Silver nanoparticles (AgNPs) offer stronger antimicrobial activity, and in situ synthesis improves stability, uniformity, cost efficiency, and bioactivity while minimising contamination. These features make AgNPs well-suited for incorporation into textiles and wound dressings. Red wine extract (RW-E), rich in antioxidant and anti-inflammatory compounds was used to hydrothermally synthesise RW-AgNPs and RW-AgNPs-loaded on cotton (RWALC) by optimising pH and RW-E concentration. Characterisation was performed using UV–Vis spectroscopy, dynamic light scattering (DLS), and High Resolution and Scanning electron microscopy (HR-TEM and SEM). Antibacterial activities were evaluated against human pathogens through agar disc diffusion assay for RWALC and microdilution assay for RW-AgNPs. RWALC showed higher potency against both Gram-negative and Gram-positive bacteria, with inhibition zones of 12.33 ± 1.15 to 23.5 ± 5.15 mm, that surpassed those of ciprofloxacin (10 ± 3 to 19.17 ± 1.39 mm at 10 μg/mL). RW-AgNPs exhibited low minimum inhibitory concentrations (MIC: 0.195–3.125 μg/mL) and minimum bactericidal concentrations (MBC: 0.78–6.25 μg/mL). Preincubation with β-mercaptoethanol (β-ME) inhibited the antibacterial activity of RWALC, suggesting that thiolated molecules are involved in AgNPs-mediated effects. This study demonstrated that green-synthesised RW-AgNPs, incorporated in situ into cotton, conferred strong antibacterial properties, warranting further investigation into their mechanisms of action. Full article

The use of natural bioactive compounds in edible coatings provides a sustainable approach to reducing food spoilage and meeting consumer demand for safer food preservation. In this study, bioactive extracts from Brassica juncea (green mustard, GM) and Raphanus sativus (radish tango, RT) sprouts were encapsulated into zein/chitosan (Z/CH) microparticles (MPs) using a complex coacervation–based encapsulation approach. The encapsulated microparticles (MPs), characterized by FTIR and UV-Vis spectroscopy, demonstrated a high loading efficiency of up to 90% and maintained their antioxidant activity for up to 168 h. TGA and SEM tests confirmed that the edible films produced by incorporating these microparticles (MPs) into polyvinyl alcohol (PVA) and chitosan (CH) matrices had a more uniform microstructure and enhanced heat stability. The Z/CH/RT6:PVA (1:2) and Z/CH/GM6:CH (1:1) formulations of the films showed significant antioxidant and antibacterial action, with up to 22.4% DPPH inhibition and a 1-log decrease in Salmonella enterica CFU, respectively. Overall, the results underscore the promise of sprout-derived microparticles as components for developing active, biodegradable packaging films with improved functional properties. Full article

Bacterial infections remain a major challenge to human health, especially in wound healing, where they can cause prolonged inflammation, delayed recovery, and severe complications. Current research is increasingly focused on developing innovative antimicrobial materials capable of overcoming the limitations of conventional antibiotics, whose effectiveness has declined due to the rise in bacterial resistance. Among the various alternatives, silver nanoparticles have gained particular attention for their broad-spectrum antibacterial properties and have already been successfully applied in the functionalization of commercial wound dressings. The aim of this study was to optimize the functionalization of commercial cotton gauzes based on in situ UV-assisted reduction of silver nanoparticles, reducing methanol usage and identifying the minimal silver nitrate precursor concentration to achieve antimicrobial efficacy while maintaining biocompatibility. Different precursor concentrations were then evaluated through cytocompatibility assays (MTT, Live/Dead, and scratch tests on fibroblasts) and antimicrobial analyses against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus (including an antibiotic-resistant strain), and Candida albicans. The results demonstrated that a 0.5% w/w silver nitrate concentration provided strong antimicrobial and antibiofilm activity without compromising textile properties or cytocompatibility. Furthermore, this optimized process reduced material waste, highlighting its potential for scalable production of antimicrobial wound dressings. Full article

Bacteriophages, traditionally viewed solely as antibacterial agents, are increasingly being studied for their immunomodulatory properties. In this study, we demonstrate that PM16 phage therapy not only effectively controls subcutaneous Proteus mirabilis infection in mice but also induces long-term specific humoral immunity against subsequent reinfection. This immunomodulatory effect was dose-dependent. In vitro, PM16 directly activates macrophages, leading to increased production of proinflammatory cytokines (tumor necrosis factor-α and interleukin-1β) and inducible nitric oxide synthase, and enhances macrophage bactericidal activity against P. mirabilis. We assume that the enhancement of the adaptive immune response is mediated not by the phage acting as a classical antigenic adjuvant but by its ability to prime innate immune cells, specifically macrophages. This priming leads to more efficient bacterial clearance, antigen presentation, and the formation of protective immunological memory. Full article

This study addresses the critical need for advanced biomedical materials that possess both potent antimicrobial properties and high biocompatibility to prevent device-related infections and promote healing. To this end, we demonstrate the successful development and comprehensive characterization of functional composite materials based on a photopolymerizable acrylate resin modified with laser-ablated copper nanoparticles (Cu NPs). The synthesized Cu NPs exhibited a monomodal size distribution with a peak at 47 nm, a high zeta potential of −33 mV, and a spherical morphology. Incorporation of Cu NPs into the polymer matrix via Masked Stereolithography (MSLA) enabled the fabrication of complex structures that maintained high surface quality and optical transparency after polishing. Modification of photopolymer resin with Cu NPs significantly increased the strength of the resulting products and caused dose-dependent formation of reactive oxygen species (ROS). The resulting composite materials exhibited strong antibacterial activity against E. coli. Crucially, despite their potent antimicrobial efficacy, the materials showed no cytotoxicity towards human fibroblast cultures. These results highlight the potential of these composites for a new generation of biomedical applications, such as implantable devices and wound coatings, which combine programmable antimicrobial activity with high biocompatibility. Full article

Staphylococcus aureus (S. aureus) is a common pathogen that threatens healthcare and food safety. Vine tea extract (VTE) and its major active component, dihydromyricetin (DMY), show antibacterial activity. However, their mechanisms of action are not fully understood. In this study, we combined proteomics and lipidomics, with RT–qPCR validation of selected differentially expressed genes, to investigate how DMY and VTE affect S. aureus. Proteomics identified 210 and 535 differentially expressed proteins (DEPs) in the DMY-treated and VTE-treated groups, respectively. These DEPs were mainly enriched in cell wall- and membrane-associated pathways. DMY markedly increased proteins involved in fatty acid degradation, glyceride metabolism, and cell wall synthesis. In contrast, VTE increased proteins related to heme/iron acquisition and cell wall degradation. In addition, VTE altered proteins involved in pyrimidine metabolism and aminoacyl-tRNA biosynthesis, suggesting that non-DMY components in VTE may contribute to the antibacterial activity through additional pathways. Lipidomics further indicated membrane lipid remodeling, including increased fatty acid unsaturation and shorter acyl chain length. Collectively, DMY and VTE may inhibit S. aureus growth by remodeling membrane lipids and disturbing cell wall–cell membrane homeostasis. These findings provide mechanistic support for further development of DMY and VTE as natural antimicrobial candidates. Full article

The development of eco-friendly antimicrobial materials is essential for addressing antibiotic resistance, while reducing environmental impact. In this study, bio-derived anionic and cationic cellulose nanofibers (a-CNF and c-CNF) were employed as templating matrices for the in situ hydrothermal synthesis of cellulose/ZnO nanohybrids. Physicochemical characterization confirmed efficient cellulose functionalization and high-quality nanofibrillation, as well as the formation of uniformly dispersed ZnO nanoparticles (≈10–20 nm) strongly integrated within the cellulose network. The ZnO content was 30 and 20 wt. % for a-CNF/ZnO and c-CNF/ZnO, respectively. Antibacterial evaluation against Escherichia coli and Staphylococcus aureus revealed enhanced activity for both hybrids, with c-CNF/ZnO displaying the lowest MIC/MBC values (50/100 μg/mL). Antiviral assays revealed complete feline calicivirus inactivation at 100 μg/mL for c-CNF/ZnO, while moderate activity was observed against bovine coronavirus, highlighting the role of surface charge. Cytotoxicity assays on mammalian cells demonstrated high biocompatibility at antimicrobial concentrations. Life cycle assessment showed that c-CNF/ZnO exhibits a lower overall environmental burden than a-CNF/ZnO, with electricity demand being the main contributor, indicating clear opportunities for further reductions through process optimization and scale-up. Overall, these results demonstrate that CNF/ZnO nanohybrids effectively combine renewable biopolymers with ZnO antimicrobial functionality, offering a sustainable and safe platform for biomedical and environmental applications. Full article

The global prevalence of antibiotic-resistant bacteria, such as Staphylococcus aureus, presents a substantial challenge to public health, necessitating the development of innovative therapeutic strategies to combat these infections. This study examined the synergistic effects of a biosurfactant (BS) derived from Lactiplantibacillus plantarum and a novel extract from Rosmarinus officinalis (RoME) obtained through supercritical CO₂ extraction against S. aureus sourced from the microbiology laboratory at King Salman Hospital in Ha’il, Saudi Arabia. Antibacterial efficacy was determined using minimum inhibitory concentration (MIC) assays, assessments of bacterial membrane damage, and qRT-PCR analysis of genes associated with antibiotic resistance. The findings revealed that the S. aureus strain exhibited resistance to multiple antibiotics with a resistance score of 0.44. RoME and BS demonstrated MICs of 0.125 mg/mL and 0.5 mg/mL, respectively. The assays indicated significant bacterial membrane damage and reduced expression of the norA, mdeA, and sel genes, which are implicated in resistance and virulence, respectively. The combination of BSs with plant extracts may provide innovative approaches for treating infections caused by multidrug-resistant bacteria, highlighting the potential of probiotic-derived BSs in combination with plant extracts. Full article

Canal wall down mastoidectomy (CWD) effectively eradicates cholesteatoma and chronic otitis media but frequently results in a problematic open mastoid cavity. Mastoid obliteration aims to reduce cavity-related morbidity. Bioceramic materials, including hydroxyapatite (HA), tricalcium phosphate (TCP), and bioactive glass (BAG), have been increasingly adopted because of their osteoconductive, biocompatible, and antimicrobial properties. This systematic review evaluates the clinical outcomes and complications of bioceramic mastoid obliteration following CWD. A systematic literature search of PubMed, Scopus, and Web of Science was conducted for studies published between 2005 and 2025, following PRISMA guidelines. Clinical studies reporting outcomes of bioceramic mastoid obliteration after CWD were included. Thirteen clinical studies were included. HA-, TCP-, and BAG-based materials demonstrated high obliteration success rates (>90% in most series). BAG S53P4 was consistently associated with low infection rates and favorable epithelialization, whereas earlier HA cement formulations were occasionally associated with revision-requiring complications. Bioceramic scaffolds represent safe and effective materials for mastoid obliteration after CWD. BAG offers additional antibacterial advantages, while HA provides predictable volume stability. Further prospective and comparative studies are required to establish material superiority and long-term outcomes. Full article

The increasing prevalence of multidrug-resistant (MDR) Campylobacter species poses a serious threat to food safety and public health, highlighting the urgent need for natural antimicrobial alternatives to conventional antibiotics. This study investigated the antibacterial potential and mechanism of action of seven essential oils (EOs), Cymbopogon citratus, Mentha pulegium, Artemisia absinthium, Myrtus communis, Thymus algeriensis, Thymus capitatus, and Eucalyptus globulus, against multidrug-resistant Campylobacter jejuni and Campylobacter coli. The antimicrobial activity was first assessed by the agar disk diffusion and broth microdilution methods to determine inhibition zones, minimum inhibitory concentrations (MICs), and minimum bactericidal concentrations (MBCs). The most active EOs were further evaluated through time–kill kinetics, cell lysis, salt tolerance, and membrane integrity assays to elucidate their bactericidal mechanisms. Results showed that E. globulus, T. algeriensis, and M. communis exhibited the strongest inhibitory effects, particularly against C. jejuni, with MIC values ranging from 3.125% to 6.25%, while C. coli was more resistant. Time–kill and lysis experiments demonstrated rapid bacterial reduction and significant decreases in optical density, indicating cell disruption. Additionally, EO treatments reduced salt tolerance and induced leakage of cytoplasmic materials, confirming membrane damage. Overall, these findings suggest that selected essential oils exert potent antimicrobial effects through membrane disruption and osmotic imbalance, offering promising natural strategies to control MDR Campylobacter in food systems. The application of such bioactive compounds could contribute significantly to improving food quality, extending shelf life, and enhancing food safety. Full article

Currently, the increased incidence of invasive fungal infections globally is posing a significant challenge to public health. Due to drug resistance issues, the clinical efficacy of existing antifungal drugs is seriously insufficient, while new drug development progresses slowly. Consequently, there is an urgent need to discover and develop novel antifungal therapeutics. Natural products have the characteristics of wide sources and few adverse reactions and are one of the sources for developing antifungal drugs. Numerous studies have shown that many compounds isolated from plants and traditional Chinese medicine have antifungal activity and diverse antifungal mechanisms. Thymol, a monoterpene phenol compound from thyme (Lamiaceae), has multiple biological functions such as antibacterial, antioxidant, and anti-inflammatory. Recent research has found that thymol has strong antifungal activity, and its molecular mechanisms involve cell membrane rupture, interference with cell wall synthesis, disruption of mitochondrial function and energy metabolism, inhibition of biofilm, inhibition of virulence factor expression, inhibition of key enzymes, and induction of cell apoptosis. This review aimed to summarize the antifungal activity of thymol and the underlying molecular mechanisms, safety, and potential clinical applications. Emerging technologies in thymol delivery systems and future research directions are also discussed. The comprehensive analysis aims to provide a detailed understanding of fungal infections and the role of thymol in antifungal treatment, offering insights for further research and clinical practice. Full article