Search Results (8,200)

Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa rank among the most challenging pathogens due to increasing prevalence of multidrug-resistant (MDR) strains. These pathogens pose major risks to public health and food safety, earning their inclusion on the World Health Organization (WHO) priority list of MDR bacteria. While available conventional antibiotics are becoming less effective, natural products from plant extracts offer promising alternative and synergetic effects that can restore efficacy and lower required doses. Their antimicrobial activity is attributed to phytochemicals such as phenolic compounds and terpenoids acting via membrane disruption, efflux pump inhibition, biofilm interference, and cell protein disruption. Furthermore, phytochemicals in essential oils, such as carvacrol, thymol, and cinnamaldehyde, also exhibit antimicrobial and antioxidant activities. Their broad antimicrobial effects extend shelf life and enhance food safety, making them effective natural alternatives to synthetic preservatives. Moreover, advances in extraction and characterization techniques, including green solvents, spectrometry and hyphenated chromatographic methods, have improved recovery, identification and quantification. In addition, artificial intelligence (AI) emerges as a transformative tool to accelerate discovery, optimize compound screening, and predict synergistic interactions. Notwithstanding these advances, challenges persist in standardization, bioavailability, and clinical translation. Further studies are needed to isolate active compounds, elucidate mechanisms of action, validate combined use with conventional antibiotics and overcome formulation, delivery, sensory and regulatory hurdles. This review examines current knowledge of opportunities and limitations of plant-based antimicrobials against MDR pathogens supported by advances in extraction, characterization, and AI. Full article

This study investigated the antimicrobial potential of Coptis chinensis rhizome extract against key oral pathogens and evaluated the safety and clinical efficacy of a CCE-loaded mouthwash. CCE exhibited broad-spectrum bactericidal activity, with low minimum inhibitory concentrations (0.002–0.008%) and minimum bactericidal concentrations (0.004–0.016%) against Streptococcus mutans, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis. Time-kill kinetics revealed that CCE promptly eradicated Porphyromonas gingivalis. To balance antimicrobial potency and sensory acceptability, specifically the extract’s bitterness, we established the CCE concentrations in the mouthwash at 0.01% and 0.02% (w/v). Preclinical safety evaluations in animal models, including oral mucosal irritation and skin sensitization tests, confirmed the biocompatibility of 0.02% CCE, yielding “None” and “Non-sensitizer” ratings, respectively. Furthermore, a four-week, randomized, double-blind clinical trial (n = 73) revealed that 0.02% CCE mouthwash substantially reduced halitosis-inducing volatile sulfur compounds (hydrogen sulfide by 59.5% and methyl mercaptan by 50.0%). Significant improvements were also observed in the Plaque Index (55.2% reduction), Gingival Index (52.0% reduction), and Bleeding on Probing (77.3% reduction), with no adverse effects. These findings provide preliminary evidence that CCE mouthwash improves halitosis-related parameters and gingival indices in adults with self-reported halitosis, though further research is required to evaluate its long-term impact on broader periodontal disease states. Full article

Oral candidiasis (OC) is the most frequent fungal infection among users of dental prosthetic devices, immunocompromised patients, and those who underwent chemotherapy treatment and had a complication of long-term antibiotic therapy. About 150 species of Candida fungi have been described, whereas over 80% of oral fungal infections are attributed to the opportunistic pathogen Candida albicans. Pain, dryness of oral mucosa, pathological lesions, and intermittent mucosal bleeding are the main symptoms that worsen the daily functioning of the abovementioned fungal-infected patients. A promising adjunctive strategy may involve the use of probiotic bacteria to attenuate fungal colonization in the oral cavity in order to reduce the need for conventional treatment, which carries a risk of antifungal drug resistance—a significant problem worldwide. Probiotic formulations mostly incorporate commensal bacteria that naturally inhabit oral ecosystems such as Lactobacillus spp., Bifidobacterium spp., Bacillus spp., and others. Probiotic organisms may contribute to the restoration of oral microbiome homeostasis through numerous mechanisms, such as competitive control of Candida species numbers, better adhesion to oral mucosa and production of bioactive compounds and antimicrobial metabolites. Despite many studies, the current evidence base remains heterogeneous. Well-designed studies across diverse populations are required to determine whether probiotic-based interventions can be an effective and clinically useful alternative or adjunct to standard antifungal therapy of OC. Full article

Endophytic bacteria from plants adapted to arid and semi-arid environments represent an underexplored reservoir of microbial diversity with potential agricultural applications. Here, we report a polyphasic taxonomic and genome-based characterization of Achromobacter sp. isolates recovered from root and foliar tissues of Citrullus colocynthis and Peganum harmala, two medicinal plants thriving under harsh environmental conditions. Whole-genome sequencing, phylogenomic analyses, average nucleotide identity (ANI), digital DNA–DNA hybridization (dDDH), multilocus sequence typing, and detailed phenotypic profiling revealed three previously undescribed species, for which we propose the names Achromobacter colocynthi sp. nov., Achromobacter maghribensis sp. nov., and Achromobacter semiaridum sp. nov. Genome assemblies were highly complete (98.7–99.2%) with minimal contamination (<1%), supporting robust taxonomic inference. All three species displayed ANI and dDDH values below accepted thresholds relative to their closest phylogenetic neighbors, despite partial inconsistencies in 16S rRNA similarity for one isolate, highlighting the value of genome-wide metrics for species delineation. Phylogenomic analyses placed the novel taxa within Achromobacter sp. as distinct evolutionary lineages. Phenotypic characterization indicated broad metabolic versatility, including utilization of carbohydrates, organic acids, and amino acids, tolerance to moderate salinity and acidic pH, and resistance to multiple antimicrobial compounds, traits likely linked to adaptation to endophytic lifestyles under semi-arid conditions. Beyond their taxonomic novelty, the isolates exhibited in vitro traits associated with plant adaptation and stress tolerance, including IAA production, ACC deaminase activity, and tolerance to Zn, Cu, and Cd. Genomic analyses further indicated functions related to phosphate acquisition and stress response. These findings expand the taxonomic framework of Achromobacter sp., establish C. colocynthis and P. harmala as reservoirs of novel endophytic bacteria, and highlight their potential relevance for agricultural biotechnology in stress-prone environments. Full article

Sea fennel is a halophyte plant recognised as a valuable source of phenolics with good antioxidant and antimicrobial potential. In this study, accelerated solvent extraction (ASE) was optimised to improve the recovery of phenolic compounds from sea fennel, particularly hydroxycinnamic acids, which are known to be dominant. The effect of the applied extraction temperature (20–120 °C) and used solvent (20–80% hydroethanolic mixtures) on total phenolic content (TPC) was systematically evaluated. Individual phenolic composition, antioxidant activity, and antimicrobial properties were measured in the top four samples. TPC was determined spectrophotometrically, while individual compounds were analysed by chromatography. Antioxidant (reducing and free-radical scavenging) activity was assessed using three assays, while the minimum inhibitory concentrations and minimum bactericidal concentrations were determined using the microdilution method against five bacterial strains. Both temperature and solvent composition significantly influenced phenolic extraction efficiency. The highest TPC and concentrations of chlorogenic acid and its derivatives were obtained at 60 °C using 60–80% ethanol (664 and 673 mg of gallic acid equivalents/g of dry extract), while higher temperatures generally resulted in reduced phenolic yield. Extracts obtained under optimal ASE conditions exhibited enhanced antioxidant activity and moderate antimicrobial effects, particularly against Gram-positive bacteria, which demonstrates that accelerated solvent extraction represents an efficient approach for obtaining sea fennel extracts rich in valuable bioactives with potential use in different industries. Full article

This study investigated the use of aqueous pomegranate (Punica granatum L.) leaf extracts as a source of bioactive compounds in edible coatings for strawberry postharvest preservation. Extraction conditions were evaluated by varying solid-to-solvent ratio, temperature, and time, using total phenolic content (TPC) as the response variable. Response surface analysis indicated that the best predicted extraction conditions within the studied range were 1:50 (w/v), 57.36 °C, and 25 min. Among the evaluated treatments, extract C503 (1:50 (w/v), 50 °C, and 25 min) showed the highest experimental TPC (474.62 ± 21.69 mg GAE/g DM) and was selected for further characterization. This extract also showed high antioxidant capacity (FRAP: 7085 ± 72.0 µM FeSO₄/g; ABTS: 4921 ± 149.0 µM Trolox/g) and antimicrobial activity against Listeria monocytogenes and Staphylococcus aureus. When incorporated into gelatin- and starch-based edible coatings and applied to strawberries, both coatings reduced mass loss and delayed deterioration during nine days of storage at room temperature. At the end of storage, mass loss was reduced by approximately 25% with the gelatin-based coating and 11% with the starch-based coating. These results support aqueous pomegranate leaf extract as a promising source of bioactive compounds for the development of sustainable edible coatings to improve strawberry preservation. Full article

Pyrolysis liquid (PL) derived from biomass pyrolysis exhibits biopesticidal properties and represents a promising value-added product within the sustainable circular economy framework. However, knowledge about the antimicrobial potential of PLs produced from walnut residue at different pyrolysis temperatures remains limited. We investigated the chemical composition and antimicrobial activity of PLs obtained from agricultural walnut residue (Juglans regia L.) against selected plant pathogenic bacteria and fungi. PLs were produced at four temperature ranges: 200–300 °C (W-1), 300–400 °C (W-2), 400–500 °C (W-3), and 500–600 °C (W-4). Chemical characterization was performed using Gas chromatography–mass spectrometry (GC-MS), High-performance liquid chromatography (HPLC), and Inductively coupled plasma optical emission spectrometry (ICP-OES), with determination of total phenolic and flavonoid contents. Pyrolysis temperature significantly influenced the chemical profile and bioactive compound content of the PLs, with W-4 showing the highest total phenolic and flavonoid levels. Heavy metal analysis indicated minimal contamination in all samples. Antibacterial activity was observed in stock solutions, whereas diluted applications showed limited effects. The W-4 fraction showed the strongest antibacterial activity and exhibited MIC values of 12.50 µL/mL against Clavibacter michiganensis subsp. michiganensis, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. syringae, and 25.00 µL/mL against Erwinia amylovora. Antifungal activity differed markedly across temperature ranges, with W-3 and W-4 displaying superior activity against Fusarium oxysporum and Verticillium dahliae, achieving complete mycelial growth inhibition at 5%, compared to 10% for W-2 and 20% for W-1. Positive controls confirmed assay validity (ciprofloxacin for antibacterial assays and cycloheximide for antifungal assays), whereas negative controls showed no inhibitory effect. Overall, higher pyrolysis temperatures, particularly 400–600 °C, enhanced the antimicrobial potential of walnut residue-derived PLs, supporting their possible use as bio-based antifungal agents for sustainable crop protection. Full article

This study evaluated the effects of light spectral quality on shoot yield and essential oil of Tagetes erecta L. cultivated in controlled growth chambers under three LED lighting treatments with different red, blue, and white wavelength ratios and a constant 16 h photoperiod for up to 101 days. The F2 treatment (5 red:1 blue) produced yields of fresh shoots, early blooming flowers, and oils of 1586 ± 164 g/m², 569.77 ± 76.81 g/m², and 307 ± 31.7 mg/m², respectively. These values were significantly higher (p < 0.05) than those of the F1 treatment (white:red-phosphor), and represented increases of 1.37-, 1.26-, and 1.38-fold, respectively. Gas chromatography identified 30–31 compounds in the oil with three major constituents—(E)-β-ocimene (22.9–28.8%, highest under F3), (E)-myroxide (13.9–20.6%, highest under F1), and piperitone (7.3–9.6%, highest under F3). Essential oils inhibited from four to five of the seven tested microbial strains, with the notable activity against Escherichia coli and Candida albicans recorded in F2 and F1, respectively. These findings confirm that light spectral quality is a critical factor regulating flower, essential oil, and antimicrobial efficacy in T. erecta, demonstrating that optimized LED spectra offer a practical strategy to improve plant yield and phytochemical quality. Full article

Conventional and emerging extraction methods for recovering phenolic compounds (PCs) from Pinus radiata bark were investigated for their potential use in bio-composites and bio-based biomaterial applications. To optimize the recovery process, a Response Surface Methodology (RSM) based on a Box–Behnken design was used to evaluate the effects of extraction time (20–100 min), temperature (20–80 °C), and water or ethanol-water solvent concentrations with β-cyclodextrin (βCD) or NaOH (0.5–1.5% w/v CD/db). Polyphenolic profiles of the extracts were characterized using Fourier transform infrared spectroscopy (FTIR), LC-LTQ-Orbitrap-MS, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to evaluate the thermal stability and degradation behavior of the powdered extracts. Antioxidant capacity (DPPH, FRAP, ABTS) and antibacterial activity against Escherichia coli and Staphylococcus aureus were assessed by spectrophotometric assays and the agar diffusion method, respectively. Highest extraction yields were obtained using alkaline extraction (14.32%) and ultrasound-assisted extraction (UAE) (13.86%), followed by ethanol extraction (12.74%). Minimum inhibitory concentration (MIC) for P-βCD was 0.04 mg/mL, and the minimum bactericidal concentration (MBC) was 0.32 mg/mL against S. aureus. These results suggest a strong inhibitory capacity at low concentrations and the potential incorporation of these extracts into bio-based antimicrobial biomaterials. Full article

Background/Objectives: The purpose of this study was the chemical design, synthesis, and evaluation of the antimicrobial and antibiofilm potentials of 20 novel thiazolyl-methylthio-thiadiazole hybrid compounds (6a–j and 8a–j). Methods: The compounds were designed as structural analogues of halicin with two points of variation and were synthesized through a process with multiple condensation steps. The compounds were evaluated in vitro through MIC determinations for the antimicrobial activity and percentage of biofilm inhibition, and in silico, respectively, through molecular docking, druggability, and ADMETox prediction. A 2D-QSAR study was conducted for antimicrobial activity using the Free-Wilson model. Results: In terms of antibacterial activity, all compounds displayed important activity on the tested strains (MICs = 15.62–250 μg/mL), except against Staphylococcus aureus. Regarding the antifungal activity, the effect against Candida albicans was similar to fluconazole in most cases (MIC = 15.62 μg/mL). With respect to the antibiofilm activity, the most effective activity was registered against the Pseudomonas aeruginosa biofilm. The in vitro results for the antibacterial activity against Escherichia coli were correlated with the observations drawn in the molecular docking study on the ATPase domain of the GyrB subunit of E. coli. The in silico predictions of the molecular properties concluded that all compounds have good druggability properties, while the ADMETox predictions concluded that the compounds could have low gastrointestinal absorption and blood–brain barrier permeation capacity, but raised safety flags (e.g., hepatotoxicity and high acute oral toxicity). The 2D-QSAR study concluded that the thiazolyl-methylthio-thiadiazole scaffold had the highest contribution to antimicrobial activity in almost all cases. Conclusions: The two series of compounds highlight the impact of structural modulations of the scaffold and its substituents on the investigated biological activities. Full article

Antimicrobial resistance (AMR) represents a major global health threat, largely driven by antibiotic overuse and the protective role of bacterial biofilms. Quorum sensing (QS), a bacterial communication system regulating virulence and biofilm formation, has emerged as a promising therapeutic target. Quorum quenching (QQ), which disrupts QS without directly inhibiting bacterial growth, is considered a potential anti-virulence strategy that may reduce selective pressure for resistance. This review critically evaluates recent advances in QQ research, focusing on its clinical applicability, limitations, and risks. We analyzed studies from the last five years involving natural compounds, synthetic molecules, nanoparticles (NPs), and combination therapies targeting key pathogens such as Pseudomonas aeruginosa and Staphylococcus aureus in models of lung diseases, mainly cystic fibrosis, chronic wounds, burns, and implant-associated infections. While numerous compounds demonstrate significant in vitro anti-biofilm and anti-virulence activity, major challenges remain, including limited in vivo validation, pharmacokinetic constraints, toxicity concerns, microbiome disruption, and the potential development of tolerance or functional resistance. Although QQ offers a promising adjunctive approach to conventional antibiotics, its long-term clinical feasibility requires comprehensive evaluation of evolutionary dynamics, host–microbe interactions, and safety profiles. Full article

Parasitic plants represent a unique group of angiosperms that extract nutrients from host plants through specialized structures called haustoria. With over 4750 recognized species, these plants vary in their dependence on hosts, classified as holoparasites (completely non-photosynthetic) or hemiparasites (partially photosynthetic). Despite their parasitic lifestyle, these plants contribute significantly to ecological stability by regulating plant communities. Some parasitic species, such as Striga and Orobanche, are major agricultural pests, while others, including Cistanche and Cynomorium, are valued for their medicinal properties. Parasitic plants in general are rich in secondary metabolites with potential pharmacological significance. These compounds, including alkaloids, phenolics, and terpenoids, display antimicrobial, anticancer, and immunomodulatory effects. Mistletoe (Viscum album L.) produces lectins and viscotoxins, which exhibit cytotoxic and immune-stimulating properties. Traditional medicine has long utilized parasitic plants, and modern pharmacological research continues to uncover their potential in drug development. However, an intriguing question arises: whether they are superior in any way to their non-parasitic counterparts, or just received more attention due to their unique appearance. Understanding the unique chemistry of parasitic plants provides insights into their ecological role and offers opportunities for advancements in medicine and agriculture. Full article

Otitis externa in dogs is primarily caused by Malassezia pachydermatis. Treatment involves antifungal and antiseptic agents; however, resistance among causative organisms has been noted. Pomelo (Citrus maxima) is a source of bioactive compounds with antimicrobial activity. Its extract mainly includes essential oils, which are mostly applied for alternative treatment for M. pachydermatis. The study aimed to investigate the anti-M. pachydermatis effects of pomelo peel extracts and their potential use in topical solutions for canine infections. M. pachydermatis was isolated from dogs and confirmed with Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF/MS). Antifungal susceptibility of M. pachydermatis to itraconazole was evaluated. Phytochemicals of essential oil and crude extract from C. maxima peel were determined using Gas Chromatograph–Mass Spectrometry (GC-MS/MS). In addition, the antifungal activity of the extracts was assessed using an agar plate dilution assay. The essential oil was formulated into a prototypic topical solution, and its effects on M. pachydermatis were observed in vitro. The prevalence of M. pachydermatis was 42%, with 53% having yeast on both ear sides. The minimum inhibitory concentrations (MIC) of itraconazole, essential oil, and crude extract to M. pachydermatis were 0.03–0.25 µg/mL, 1.0% v/v, and >200 mg/mL, respectively. The prominent phytochemicals in peel extracts were meranzin hydrate and D-limonene, identified in the crude extract and essential oil, respectively. Moreover, a topical solution containing essential oils inhibited M. pachydermatis growth and showed destructive effects on the yeast cell wall at higher concentrations. The essential oil exhibits antifungal activity against M. pachydermatis, primarily due to the high concentration of D-limonene. The growth was inhibited completely at MIC, observed over a 5-day period. Furthermore, the prototypic topical solution demonstrated an anti-M. pachydermatis effect. These findings suggest potential veterinary applications for pomelo peel extract, though further studies are necessary to assess stability, mechanism of action, and industrial suitability. Full article

The genus Serjania (family Sapindaceae) comprises more than 240 species, primarily distributed in Brazil and Mexico, and it exhibits considerable ethnobotanical and therapeutic potential. Ethnobotanical evidence documents the widespread use of decoctions prepared from the leaves, stems, and roots of Serjania species for the treatment of gastrointestinal disorders, renal pain, inflammatory conditions, and infections. Among the most extensively studied species are S. marginata, S. erecta, S. lethalis, S. caracasana, S. goniocarpa, S. schiedeana, S. yucatenensis, S. triquetra, and S. racemose. Phytochemical research has identified a diverse array of bioactive secondary metabolites, including saponins, flavonoids, phenolic acids, tannins, and terpenoids. Significant experimental evidence supports the broad spectrum of biological activities of these Serjania species, including antimicrobial, anti-inflammatory, antioxidant, gastroprotective, antihypertensive, analgesic, antivenom, cytotoxic, antimutagenic, anti-ulcer, photoprotective, antiparasitic, and vasorelaxant effects, as demonstrated in both in vitro and in vivo models. Although preliminary toxicity assessments of extracts from some Serjania species in murine models, Oreochromis niloticus (Nile tilapia), and Artemia salina suggest a favorable safety profile, significant research gaps remain. Additionally, several Serjania species have shown potential as natural pesticides and bioherbicides, highlighting their relevance in agricultural applications. Future studies should prioritize the isolation and structural characterization of individual bioactive compounds, as well as the elucidation of their molecular mechanisms of action, moving beyond crude extract-based screening approaches. Overall, this review summarizes current knowledge on traditional uses, phytochemical composition, biological activities, and biotechnological applications of Serjania species. Full article

The roots of Cannabis sativa L., historically overlooked, are gaining attention as a potential source of bioactive compounds with antioxidant, antimicrobial, and anti-inflammatory properties. While previous studies have focused on extractions using ethanol, water, or supercritical CO₂, the feasibility of edible oil-based extraction remains largely unexplored. This study evaluated the extraction of root compounds using hemp seed oil, MCT coconut oil, and grape seed oil at six temperatures (50–90 °C). Extracts were analyzed by GC–MS for compound identification and quantification, and antioxidant activity was assessed using the DPPH assay, ABTS test and β-carotene bleaching method, with results statistically evaluated by ANOVA. Friedelin was successfully extracted with all oils, with grape seed oil yielding the highest concentration (0.810 mg/g dry roots), achieving recoveries higher than those previously reported for ethanol-based extractions. All extracts demonstrated positive antioxidant activity, with grape seed oil, both alone and combined with extracts, showing higher values across the three methods. ANOVA revealed a significant effect of solvent type on both Friedelin concentration and antioxidant capacity. These results demonstrate that edible oils are effective solvents for extracting bioactive compounds from C. sativa roots, supporting their potential application in cosmetic or medicinal formulations. Full article