Search Results (227)

The European chestnut (Castanea sativa Mill.) industry generates substantial amounts of underutilized biomass, including shells, leaves, and spiny burs. Distinguishing itself from existing literature, this review presents a novel, integrated life-science analysis that redefines these by-products as a complementary ‘bioactive triad’, ranging from metabolic regulators to anti-virulence agents, rather than interchangeable sources of polyphenols. Although traditionally discarded, these by-products are rich sources of polyphenols, ellagitannins, and flavonoids, with promising potential for nutraceutical, cosmetic, and pharmaceutical applications. This review examines recent advances in the valorization of chestnut by-products, focusing on extraction strategies, chemical profiles, and biological activities. Shell valorization has increasingly shifted toward green extraction technologies, such as subcritical water extraction and deep eutectic solvents, which strongly influence bioactive recovery and composition. Chestnut leaves emerge as a sustainable resource enriched in hydrolysable tannins with anti-inflammatory and quorum sensing-inhibitory properties, particularly relevant for dermatological applications. Spiny burs, often the most phenolic-rich fraction, display marked antioxidant activity and the ability to potentiate conventional antibiotics against pathogens such as Helicobacter pylori. Despite these promising features, major challenges remain, including cultivar-dependent chemical variability, the predominance of in vitro evidence, and safety concerns related to the accumulation of potentially toxic elements. Overall, while chestnut by-products represent valuable resources within circular bioeconomy frameworks, their successful industrial and practical translation will require standardized extraction protocols, robust bioavailability assessments, and well-designed in vivo and clinical studies to ensure safety and efficacy. Full article

Microbial contamination of food is a crucial cause of food spoilage and foodborne diseases, posing a severe threat to global public health. Although chemical preservatives are effective, their potential hazards to human health and the environment, coupled with the growing demand for “clean label” products, have driven the search for natural alternatives. Lactic acid bacteria (LAB), recognized as the Generally Recognized as Safe (GRAS) microorganisms, have emerged as the promising bio-preservatives due to their safety, effectiveness, and multifunctionality. This review systematically summarized the core antimicrobial properties of LAB, including their inhibitory spectrum against foodborne pathogens, spoilage microorganisms, viruses, parasites, and their ability to degrade toxic substances such as mycotoxins, pesticides, and heavy metals. Key inhibitory mechanisms of LAB are highlighted, encompassing the production of antimicrobial metabolites, leading to metabolism disruption and cell membrane damage, nutrition and niche competition, quorum-sensing interference, and anti-biofilm formation. Furthermore, recent advances in LAB applications in preserving various food matrices (meat, dairy products, fruits and vegetables, cereals) are integrated, including their roles in enhancing food sensory quality, extending shelf life, and retaining nutritional value. The review also discusses critical factors influencing LAB’s inhibitory activity (medium composition, culture conditions, ionic components, pathway regulator, etc.) and the challenges associated with the application of LAB. Finally, future research directions are outlined, including the novel LAB and metabolites exploration, AI-driven cultural condition optimization, genetic engineering application, nano-encapsulation and active packaging development, and building up the LAB-based cellular factories. In conclusion, LAB and their antimicrobial metabolites hold great promise as green and safe food preservatives. This review is to provide comprehensive theoretical support for the rational improvement and efficient application of LAB-based natural food preservatives, contributing to the development of a safer and more sustainable food processing and preservation systems. Full article

Foodborne diseases remain a major global challenge because pathogenic microorganisms persist in food systems, often protected by biofilms and increasing resistance to conventional chemical preservatives and sanitizers. Control strategies that were effective in the past are becoming less reliable in complex processing environments, creating a need for more precise and adaptable food-safety approaches. This review examines emerging technologies that shift food safety from broad, reactive control toward targeted, data-driven intervention. Biological tools, including bacteriophages, phage-derived enzymes, bacteriocins, quorum-sensing inhibitors, and gene-guided antimicrobial systems, are discussed for their capacity to selectively control specific pathogens while limiting unintended effects on beneficial microbiota. The review also addresses nano-enabled strategies that improve antimicrobial stability, delivery, and performance, along with plant-derived and microbial bioactive compounds that support clean-label and sustainable preservation. In parallel, advances in anti-biofilm surface engineering, such as nano-textured, contact-active, and responsive materials, are examined as preventive measures to reduce microbial attachment and persistence on food-contact surfaces. Beyond individual interventions, this review emphasizes integration within coordinated multi-hurdle systems supported by real-time monitoring and predictive analytics. Emerging digital frameworks, including digital twins of food-processing lines, are highlighted as tools to link detection, risk prediction, and targeted control. Finally, remaining knowledge gaps, regulatory challenges, and research priorities are identified, highlighting the need for realistic testing, long-term safety evaluation, standardized validation, and collaborative efforts to translate precision food-safety technologies into dependable real-world applications. Full article

Repeat-in-toxin (RTX) toxins are calcium-dependent exoproteins secreted by diverse Gram-negative bacteria and play central roles in cytotoxicity, immune modulation, and tissue colonization. While their structure and secretion mechanisms are well-characterized, the regulation of RTX toxin expression remains complex and species-specific. This review provides a comprehensive overview of the regulatory networks governing RTX gene expression, highlighting both conserved mechanisms and niche-specific adaptations. RTX genes are controlled by multilayered regulatory systems that integrate global transcriptional control, metabolic regulation, and environmental sensing. Expression is further shaped by host-derived signals, physical contact with host cells, and population-dependent cues. Quorum sensing, post-transcriptional regulation by small RNAs, and post-translational activation mechanisms contribute additional layers of control to ensure precise regulation of toxin production. We also explore how RTX regulation varies across anatomical niches, including the gut, lung, bloodstream, and biofilms, and how it is co-regulated with broader bacterial virulence. Finally, we discuss emerging insights from omics-based approaches and the potential of anti-virulence strategies targeting RTX regulatory pathways. Together, these topics underscore RTX regulation as a model for adaptive virulence control in bacterial pathogens. Full article

Microbial biofilms pose significant medical and industrial challenges due to their resistance to conventional antimicrobials, accounting for 40–80% of bacteria in various environments. This resistance primarily results from the extracellular polymeric matrix, a protective network of sugars, proteins, and other molecules produced by bacteria. The matrix restricts antibiotic penetration, facilitates microbial communication, and retains nutrients. Consequently, novel strategies to counteract biofilms are under investigation. Fatty acids have emerged as promising prebiotic agents, defined as substances that stimulate the growth of beneficial bacteria. These compounds can disrupt biofilm structure and increase microbial susceptibility to treatment. Short- and medium-chain fatty acids demonstrate direct antimicrobial activity and can alter microbial community composition, thereby inhibiting biofilm formation in several pathogens, including oral species. For instance, omega-3 fatty acids effectively inhibit Staphylococcus aureus and Pseudomonas aeruginosa biofilms through membrane disruption and quorum sensing (QS) inhibition. Additionally, long-chain fatty acids, particularly omega-3 and omega-6 polyunsaturated fatty acids, exhibit anti-inflammatory and antibacterial properties. This review synthesises current evidence on fatty acids as prebiotics, emphasising their mechanisms of action and therapeutic potential against drug-resistant biofilm-associated infections. Given the increasing prevalence of antimicrobial resistance, unsaturated and essential fatty acids rep-resent promising candidates for innovative biofilm-control strategies. Full article

Background: Infections caused by Staphylococcus aureus are a health problem worsened by antibiotic resistance. New drugs, including those inhibiting virulence and resistance mechanisms, are needed. This study aimed to evaluate the anti-growth, anti-virulence, and anti-biofilm activities of Trametes villosa. (2) Methods: Fractions were obtained from the basidiomata of T. villosa. Anti-growth, anti-hemolysis, and anti-biofilm activities were tested against S. aureus strains using resazurin microtiter, blood cell lysis, and crystal violet assays, respectively. Cytotoxicity was evaluated in Vero and HaCaT cells using sulforhodamine B. The active fractions were subjected to GC-MS analysis and molecular docking with S. aureus quorum-sensing receptors. Results: The n-hexane and ethyl acetate (EtOAc) fractions exhibited anti-growth activity against all strains (MIC: 31.2–2000 µg/mL). These fractions also displayed anti-hemolysis (IC₅₀ = 33.8 ± 1.1–53.8 ± 5.1 µg/mL) and anti-biofilm formation activity (IC₅₀ = 106.6 ± 4.8–383.4 ± 31.4 µg/mL), while exhibiting low cytotoxicity in Vero and HaCat. GC-MS analysis revealed that both active fractions mainly contained alkanes, aldehydes, and fatty acids. Molecular docking revealed that isovanillic acid, identified in the EtOAc fraction, exhibited optimal interactions with S. aureus quorum-sensing receptors AgrA and SarA. (4) Conclusions: Our research highlights the potential of T. villosa as a source of bioactive compounds effective against S. aureus. Full article

Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs) and a major contributor to the global antimicrobial resistance crisis. The increasing prevalence of multidrug-resistant (MDR) strains, including expanded-spectrum β-lactamases (ESBL) and carbapenemase-producing isolates, severely limits treatment options. This review provides an overview on the key molecular mechanisms of UPEC antibiotic resistance, such as enzymatic inactivation, target-site mutations, efflux pump activity, and biofilm formation. Beyond conventional antibiotics, special emphasis is placed on phytochemical strategies as promising alternatives. Flavonoids, alkaloids, terpenoids, and essential oils exhibit antibacterial, anti-adhesive, and antibiofilm properties. These natural bioactive compounds modulate motility, suppress fimbrial expression, inhibit quorum sensing, and enhance antibiotic efficacy, acting both as standalone agents and as adjuvants. Current in vitro and in vivo studies highlight the potential of plant-derived compounds and biologically based therapies to combat UPEC. However, challenges related to standardization, bioavailability, and clinical validation remain unresolved. Integrating molecular mechanistic insights with advanced phytochemical research may offers a sustainable and effective strategy for mitigating UPEC antibiotic resistance. Full article

Background/Objectives: Staphylococcus aureus is a well-known opportunistic pathogen that causes a wide range of infections, from cutaneous blemishes to potentially fatal systemic diseases. The increasing prevalence of antibiotic-resistant bacteria highlights the critical need for alternative therapeutic methods that target virulence factors rather than growth. Methods: The antibacterial activity of 3-fluorocatechol (3-FC) against bacterial and fungal pathogens (e.g., Candida albicans) was determined by broth microdilution to establish the lowest inhibitory concentration. The antibiofilm impact of 3-FC against S. aureus was evaluated using crystal violet staining and viable colony counts, followed by scanning electron microscopy to visualize the biofilm architecture. The methanol extraction method was used to quantify staphyloxanthin synthesis in S. aureus cells. Furthermore, in silico molecular docking was used to evaluate 3-FC binding interactions and provide mechanistic insight into its impacts on S. aureus biofilms and virulence-associated factors. Results: Although the study showed that 3-FC exhibits weak antibacterial activity against S. aureus (MIC > 2048 µg/mL), it shows effective inhibition of up to 86.5% at sub-inhibitory doses during the initial stage of biofilm formation. The CFU enumeration also confirms the significant reduction of viable cell count of S. aureus in the presence of sub-MIC of 3-FC. The SEM analysis confirms disruption of the S. aureus biofilm architecture in the presence of a sub-MIC of 3-FC. Furthermore, the eradication of mature S. aureus biofilm at a sub-MIC dose of 3-FC was 60.6%. 3-FC significantly reduced staphyloxanthin formation, a vital antioxidant pigment that contributes to bacterial pathogenicity, with a maximal suppression of 66.3% at 2048 µg/mL. Molecular docking analyses provide further insight into the molecular basis of 3-FC activity, revealing strong binding affinities with numerous S. aureus virulence regulators and enzymes, suggesting interference with quorum-sensing, adhesion, and oxidative-stress response pathways. Conclusions: Collectively, our findings indicate that 3-FC has antibiofilm and antivirulence properties against S. aureus. Furthermore, this study suggests 3-FC as a viable structural scaffold for the development of a novel anti-infective agent to treat chronic staphylococcal infections. Full article

This study aimed to evaluate the antibacterial activity of Cistus salviifolius L. and Helichrysum stoechas (L.) DC extracts against S. aureus, including methicillin-resistant S. aureus (MRSA) strains. To this end, assays were conducted to assess killing kinetics, antibiotic combination effects, modulatory effects on ethidium bromide, inhibition of quorum sensing, and biofilm formation. H. stoechas extract demonstrated the strongest activity, with MIC values ranging from 7.8 to 62.5 µg/mL. When combined with antibiotics such as ampicillin, ciprofloxacin, or vancomycin, the extracts of C. salviifolius and H. stoechas predominantly exhibited synergistic (FICI value ≤ 0.5) or additive effects (0.5 < FICI ≤ 1), with some combinations resensitizing resistant strains. The aerial parts of C. salviifolius displayed modulatory effects on ethidium bromide MIC, reducing the concentration from 32 to 8 µg/mL, suggesting efflux pump inhibitory activity. In addition, this extract displayed slight quorum-sensing inhibition at a concentration of 125 µg/mL. Moreover, C. salviifolius and H. stoechas extracts inhibit the formation of biofilm by S. aureus strains, even at subinhibitory concentrations (0.5× and 0.25× MIC). The presence of compounds such as myricetin 3 O-galactoside, catechin derivatives, gallic acid, kaempferol, and chlorogenic acid in the extracts may contribute to their anti-Staphylococcus activity. These results demonstrated the dual antimicrobial and antivirulence potential of C. salviifolius and H. stoechas extracts, highlighting their promise as therapeutic agents or adjuvants against S. aureus. These extracts can be promising candidates for further studies on the development of novel strategies targeting multiple pathogenic pathways. Full article

Unlike sucrose, sucralose is a non-cariogenic artificial sweetener, commonly included in dental care products such as chewing gums, toothpastes, and mouth rinses to enhance palatability for consumers. While its non-cariogenic action is well established, there is limited evidence regarding the potential anti-cariogenic mechanisms of sucralose. This study investigated whether sucralose interferes with QS involved in oral bacterial biofilm formation. A representative LuxR-type QS regulator, LasR, was expressed in the presence of sucralose and/or its native ligand, N-acyl homoserine lactone (AHL). The expressed protein was purified using nickel-affinity chromatography and quantified by the Bradford assay. The findings reveal that sucralose significantly inhibits AHL-dependent signaling, presumably by disrupting receptor–ligand interactions. These results provide insights into a possible molecular mechanism underlying the anti-cariogenic action of sucralose, highlighting its potential as a functional additive in oral health formulations. Full article

Essential oil-derived compounds such as eugenol, thymol, cinnamaldehyde, and carvacrol exhibit potent antimicrobial and anti-inflammatory properties, making them promising candidates for therapeutic and industrial applications. This review examines the current evidence regarding the mechanisms of action, efficacy, and ability to disrupt quorum sensing and biofilm formation of essential oil-derived compounds against a broad spectrum of Gram-positive and Gram-negative bacteria, including multidrug-resistant (MDR) strains. The anti-inflammatory activity of these compounds is also highlighted, with emphasis on their modulation of key signaling pathways such as nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs), and their ability to downregulate pro-inflammatory cytokines. However, challenges persist, including cytotoxicity at high concentrations, chemical instability, poor water solubility, and variable pharmacokinetics. Advanced delivery systems such as nano encapsulation and synergistic formulations offer potential strategies to overcome these limitations. This review highlights both the therapeutic potential and the current limitations of these natural compounds, emphasizing the need for continued research to translate preclinical findings into clinical applications. Full article

Background/Objectives: The growing threat of antimicrobial resistance has intensified the search for alternative therapeutic approaches. Quorum sensing (QS) inhibition, which disrupts bacterial communication and virulence, represents a promising approach to mitigating infection. Given the complexity of the sponge holobiont, sponge-associated microorganisms may demonstrate QS inhibitory properties and serve as potential sources of novel anti-virulence agents. This study aimed to investigate the QS inhibitory potential of sponge-associated Bacillus species against Pseudomonas aeruginosa, a multidrug-resistant pathogen that relies on QS for virulence regulation. Methods: Ninety-eight bacterial isolates were obtained from seven intertidal South African sponges. Biosensor-based sandwich assays using Chromobacterium violaceum identified 15 isolates with putative QS inhibition (QSI) activity, including five classified as Bacillus species via 16S rRNA gene sequencing. Crude extracts from these isolates, cultivated in medium Mannitol (Mann) and medium 5294, were screened for their ability to inhibit QS-regulated virulence factors in P. aeruginosa. Results: Extracts, particularly from medium 5294, exhibited significant QSI activity without cytotoxic effects. The five most potent extracts, i.e., Bacillus mobilis SP2-AB7 (5294), Bacillus wiedmannii SP5-AB7 (Mann), B. mobilis SP2-AB7 (Mann), and Bacillus cereus SP1-AB4 (Mann and 5294), inhibited both Las- and Rhl-regulated virulence factors, including pyocyanin, pyoverdine, elastase, protease, rhamnolipid production, motility, and initial adhesion, achieving inhibition rates of up to 93% (p < 0.05). Molecular analysis confirmed the presence of the aiiA lactonase gene in key isolates, while GC-MS and FTIR profiling revealed medium-specific differences in metabolite production. Conclusions: Sponge-associated Bacillus species from KwaZulu-Natal exhibit robust QSI activity against P. aeruginosa, highlighting their potential as sources of alternative anti-virulence agents. Further characterization and in vivo validation are needed to assess their therapeutic application in combatting resistant infections. Full article

Background/Objectives: The aim of the present study was to evaluate the antimicrobial, antibiofilm, anti-quorum sensing, and cytotoxic activities of the essential oils extracted from the leaves of Dorystoechas hastata Boiss & Helder. ex Bentham (Lamiaceae) (DHL-EO) as well as to determine the chemical composition of the essential oils obtained from both the leaves and roots. Methods: The essential oils of the root and leaf were extracted by the hydrodistillation method. The chemical composition of the two oils was determined by Gas Chromatography–Mass Spectrometry (GC-MS). The antimicrobial activity of DHL-EO was determined against Gram-positive, Gram-negative bacteria, and various Candida species using the broth microdilution method. Pseudomonas aeruginosa PAO1 and Chromobacterium violaceum ATCC 12472 were used for antibiofilm and anti-quorum sensing activities, respectively. The cytotoxic activity of the DHL-EO was examined by MTT assay. Results: Eucalyptol (21.3%), 2-bornanone (17.0%), and α-pinene (10.3%) were the main compounds of the DHL-EO. The root essential oil (DHR-EO) had trans-ferruginol (19.2%), guaiol (14.1%), and ar-abietatriene (14.0%) as the main components. The DHL-EO displayed weak and moderate antimicrobial activity. The DHL-EO showed moderate antibacterial activity against Staphylococcus aureus ATCC 29213 (methicillin-susceptible, MSSA) and S. aureus ATCC 43300 (methicillin-resistant, MRSA), with a MIC value of 12.5 mg/mL. The DHL-EO exhibited the strongest antifungal activity against Candida parapsilosis RSKK 994, with a MIC value of 0.78 mg/mL. It also demonstrated antifungal activity against C. parapsilosis ATCC 22019 and Candida krusei RSKK 3016, with MIC values of 3.12 mg/mL. The DHL-EO showed antibiofilm activity in a concentration-dependent manner, particularly at higher concentrations, and inhibited violacein production in a dose-dependent manner, with anti-quorum sensing activity. The DHL-EO displayed moderate cytotoxic activity against MCF-7 (IC₅₀: 110.3 μg/mL) and A549 (IC₅₀: 120.4 μg/mL) cell lines. Conclusions: The chemical composition of DHL-EO and DHR-EO showed qualitative and quantitative differences from each other in the present study. The essential oil of the leaves showed moderate cytotoxic and antibacterial activities. Full article

Food spoilage and contamination remain pressing global challenges, undermining food security and safety while driving economic losses. Conventional preservation strategies, including thermal treatments, refrigeration, and synthetic additives, often compromise nutritional quality and raise sustainability concerns, thereby necessitating natural, effective alternatives. Curcumin, a polyphenolic compound derived from Curcuma longa, has demonstrated broad-spectrum antimicrobial, antioxidant, and anti-inflammatory activities, making it a promising candidate for food preservation. However, its poor solubility, instability, and low bioavailability limit direct applications in food systems. Advances in nanotechnology have enabled the development of nanoformulated curcumin, enhancing solubility, stability, controlled release, and functional efficacy. This review examines the antimicrobial mechanisms of curcumin and its nanoformulations, including membrane disruption, oxidative stress via reactive oxygen species, quorum sensing inhibition, and biofilm suppression. Applications in active and smart packaging are highlighted, where curcumin nanoformulation not only extends shelf life but also enables freshness monitoring through pH-responsive color changes. Evidence across meats, seafood, fruits, dairy, and beverages shows improved microbial safety, oxidative stability, and sensory quality. Multifunctional systems, such as hybrid composites and stimuli-responsive carriers, represent next-generation tools for sustainable packaging. However, challenges remain with scale-up, migration safety, cytotoxicity, and potential promotion of antimicrobial resistance gene (ARG) transfer. Future research should focus on safety validation, advanced nanocarriers, ARG-aware strategies, and regulatory frameworks. Overall, nanoformulated curcumin offers a natural, versatile, and eco-friendly approach to food preservation that aligns with clean-label consumer demand. Full article