Effect of post-harvest drying period on the chemical composition of Zingiber zerumbet Sm. Rhizomes essential oil and its biological activities.

Zingiber zerumbet Sm. (Family: Zingiberaceae) is an important perennial medicinal oil-bearing herb that is native to the Southeast Asia. This study examines the impact of different durations of post-harvest shade drying (ranging from 1 to 12 months) on essential oil yield and chemical composition of Z. zerumbet, in comparison to the freshly collected oil sample. This study explores how post-harvest shade drying impact the composition and longevity of Z. zerumbet rhizomes as well as its antimicrobial, antibiofilm activity. The oils were analyzed for their chemical composition analysis using a gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The post-harvest periods of drying (1-12 months) were discovered to enhance the concentration of marker constituents in the oil. The primary constituent, Zerumbone, was detected in concentrations ranging from 69.38 ± 5.63% to a maximum of 80.19 ± 1.53% as the drying duration of the rhizome was extended. The output of the essential oil was not significantly affected by drying times; however, it did have a noticeable impact on the proportions of monoterpenes. Both disc diffusion and broth microdilution assay were used in freshly collected Z. zerumbet oil for its antimicrobial potential against S. aureus, L. monocytogens, S. hominis, Salmonella enterica serovar Typhimurium, P. aeruginosa, S. intermedius, E. coli, and C. albicans. For the first time, the oil reported to exhibit antibiofilm activity against S. aureus which was validated using fluorescence microscopy, and effectively disrupts the biofilm by 47.38% revealing that essential oil was able to disintegrate the clusters of the pathogen. Z. zerumbet rhizome oil is effective to reduce food-borne microorganisms. Therefore, its essential oil, a natural source of bioactive zerumbone, may improve flavor, aroma, and preservation.

Screening of Antimicrobial, Antibiofilm, and Cytotoxic Activities of Some Medicinal Plants from Balikesir Province, Türkiye: Potential Effects of Allium paniculatum Flower.

Objectives: Plant extracts are important natural resources that may have antimicrobial and antibiofilm effects against pathogens. This study was conducted to investigate the in vitro antimicrobial activities of methanol extracts of some medicinal plants (Achillea nobilis subspecies neilreichii (A. Kern.) Velen., Aetheorhiza bulbosa (L.) Cass, Allium paniculatum L, Asphodelus aestivus Brot., Ballota nigra L., Cistus laurifolius L., Cistus salviifolius L., Dioscorea communis (L.) Caddick and Wilkin, Galium verum L., Hypericum triquetrifolium Turra, Paliurus spina-christi Mill., Primula vulgaris Huds. subspecies rubra (Sm.) Arcang., Ranunculus arvensis L. and Teucrium polium L.) from Balikesir province in Türkiye. Materials and Methods: Preliminary antimicrobial activity screening was conducted for all extracts. Antibiofilm activity studies were conducted on mature Candida albicans biofilms. Moreover, the cytotoxicities of A. paniculatum flower extract on A549 and Vero cell lines were determined using a colorimetric tetrazolium-based assay. Results: A. paniculatum flower, P. vulgaris root, C. laurifolius, C. salviifolius, and A. nobilis displayed good activity [minimum inhibitory concentrations (MIC): 9.75, 156, 312, 312 and 312 µg/mL, respectively] against C. albicans American Type Culture Collection 10231. Biofilm studies were conducted on these plant extracts. The methanol extract of A. paniculatum flower decreased the number of C. albicans [colony-forming unit (CFU)/mL] in mature biofilm statistically at 32 x MIC and higher concentrations (p < 0.01). A. paniculatum flower extract had a cytotoxic effect (killing more than 50% of cells) at high concentrations, and its effect on Vero cells was similar to that on A549 cells. Conclusion: This study demonstrated the importance of the methanol extract of A. paniculatum flower as a natural alternative against C. albicans infections, including biofilms.

Synthesis, characterization and evaluation of in vitro potential antimicrobial efficiency of new chitosan hydrogels and their CuO nanocomposites.

The phenomenon of microbial resistance and its resulting biofilms to traditional antibiotics is worsening over time. Therefore, the discovery of alternative substances that inhibit microbial activities through mechanisms different from those of known antibiotics requires attention. So, chitosan was crosslinked using different amounts of oxalyl dihydrazide yielding four novel hydrogels; ODHCs-I, ODHCs-II, ODHCs-III, and ODHCs-IV of crosslinking degree 12.17, 20.67, 31.67, and 43.17, respectively. Different amounts of CuO nanoparticles were impregnated into ODHCs-IV, obtaining ODHCs-IV/CuONPs-1 %, ODHCs-IV/CuONPs-3 % and ODHCs-IV/CuONPs-5 % composites. Their structure was emphasized using FTIR, SEM, XRD, TEM, EDX and elemental analysis. Their in vitro antimicrobial and anti-biofilm activities improved with increasing ODH and CuONPs content. ODHCs-IV exhibited minimal inhibition concentration (2 µg/mL) against S. pyogenes that was much lower than Vancomycin (3.9 µg/mL). ODHCs-IV/CuONPs-5 % displayed better inhibition performance than Vancomycin and Amphotericin B against Gram-positive-bacteria and fungi, respectively, and comparable one to that of Vancomycin against Gram-negative-bacteria. ODHCs-IV/CuONPs-5 % displayed much lower minimal biofilm inhibition concentrations (1.95 to 3.9 µg/mL) as compared with those of ODHCs-IV (7.81 and 15.63 µg/mL), against C. albicans, S. pyogenes, and K. pneumonia. ODHCs-IV/CuONPs-5 % composite is safe on normal human cells. Oxalyl dihydrazide and CuONPs amalgamated into chitosan in one formulation promoted its antimicrobial efficiency.

Preliminary Identification and Quantification of Individual Polyphenols in Fallopia japonica Plants and Honey and Their Influence on Antimicrobial and Antibiofilm Activities.

Fallopia japonica (FJ), an invasive plant species known for its rich bioactive compounds, has been used for centuries in traditional Chinese medicine. Despite its significant beekeeping potential, this aspect of FJ remains underexplored. This research aims to investigate the antimicrobial and antibiofilm properties of FJ plants and honey. Notably, this study is the first to identify individual phenolic compounds in both FJ plant tissues and FJ honey, highlighting resveratrol as a marker of FJ honey. The study tested inhibitory activity against seven bacterial strains: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, Salmonella enteritidis, and the yeast Candida albicans. Disk diffusion and microdilution methods were used to assess antimicrobial activity, while the crystal violet staining test evaluated antibiofilm activity. Results showed that FJ plant tissues and honey exhibited strong inhibition, particularly against Gram-negative bacterial strains. The most significant inhibition of biofilm formation, by both FJ plant tissues and honey, was observed against Staphylococcus aureus and Escherichia coli. A significant positive correlation was found between antimicrobial activity and individual polyphenols, especially resveratrol. The antibacterial and antibiofilm potential of FJ plant tissues and honey suggests promising applications in sustainable beekeeping. Further research is necessary to evaluate the bioactive compounds found in FJ honey and their health effects.

HPLC, NMR Based Characterization, Antioxidant and Anticancer Activities of Chemical Constituents from Therapeutically Active Fungal Endophytes.

Fungi generate different metabolites some of which are intrinsically bioactive and could therefore serve as templates for drug development. In the current study, six endophytic fungi namely Aspergillus flavus, Aspergillus tubigenesis, Aspergillus oryzae, Penicillium oxalicum, Aspergillus niger and Aspergillus brasiliensis were isolated and identified from the medicinal plant, Silybum marianum. These endophytic fungi were identified through intra transcribed sequence (ITS) gene sequencing. The bioactive potentials of fungal extracts were investigated using several bioassays such as antibacterial activity by well-diffusion, MIC, MBC, anti-biofilm, antioxidant, and haemolysis. The Pseudomonas aeruginosa strain PAO1 was used to determine the antibiofilm activity. The ethyl acetate extract of Aspergillus flavus showed strong to moderate efficacy against Staphylococcus aureus, Escherichia coli, P. aeruginosa, and Bacillus spizizenii. Aspergillus flavus and Aspergillus brasiliensis exhibited significant antibiofilm activity with IC50 at 4.02 and 3.63 mg/ml while A. flavus exhibited maximum antioxidant activity of 50.8%. Based on, HPLC, LC-MS and NMR experiments kojic acid (1) and carbamic acid (methylene-4, 1-phenylene) bis-dimethyl ester (2) were identified from A. flavus. Kojic acid exhibited DPPH free radical scavenging activity with an IC50 value of 99.3 µg/ml and moderate activity against ovarian teratocarcinoma (CH1), colon carcinoma (SW480), and non-small cell lung cancer (A549) cell lines. These findings suggest that endophytic fungi are able produce promising bioactive compounds which deserve further investigation.

Antifungal Plant Defensins as an Alternative Tool to Combat Candidiasis.

Currently, the spread of fungal infections is becoming an urgent problem. Fungi of the Candida genus are opportunistic microorganisms that cause superficial and life-threatening systemic candidiasis in immunocompromised patients. The list of antifungal drugs for the treatment of candidiasis is very limited, while the prevalence of resistant strains is growing rapidly. Therefore, the search for new antimycotics, including those exhibiting immunomodulatory properties, is of great importance. Plenty of natural compounds with antifungal activities may be extremely useful in solving this problem. This review evaluates the features of natural antimicrobial peptides, namely plant defensins as possible prototypes of new anticandidal agents. Plant defensins are important components of the innate immune system, which provides the first line of defense against pathogens. The introduction presents a brief summary regarding pathogenic Candida species, the pathogenesis of candidiasis, and the mechanisms of antimycotic resistance. Then, the structural features of plant defensins, their anticandidal activities, their mechanisms of action on yeast-like fungi, their ability to prevent adhesion and biofilm formation, and their combined action with conventional antimycotics are described. The possible mechanisms of fungal resistance to plant defensins, their cytotoxic activity, and their effectiveness in in vivo experiments are also discussed. In addition, for the first time for plant defensins, knowledge about their immunomodulatory effects is also presented.

Photocatalytic, antimicrobial and antibiofilm activities of MgFe2O4 magnetic nanoparticles.

This study reports the antibacterial and antibiofilm activities of Magnesium ferrite nanoparticles (MgFe2O4) against gram-positive and gram-negative bacteria. The photocatalytic degradation of Carbol Fuchsin (CF) dye (a class of dyestuffs that are resistant to biodegradation) under the influence of UV-light irradiation is also studied. The crystalline magnesium ferrite (MgFe2O4) nanoparticles were synthesized using the co-precipitation method. The morphology of the resulting nanocomposite was examined using scanning electron microscopy (SEM), while transmission electron microscopy (TEM) was employed for further characterization of particle morphology and size. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) were utilized to analyze the crystalline structure, chemical composition, and surface area, respectively. Optical properties were evaluated using UV-Vis spectroscopy. The UV-assisted photocatalytic performance of MgFe2O4 nanoparticles was assessed by studying the decolorization of Carbol fuchsin (CF) azo dye. The crystallite size of the MgFe2O4 nanoparticles at the (311) plane, the most prominent peak, was determined to be 28.5 nm. The photocatalytic degradation of 10 ppm CF using 15 mg of MgFe2O4 nanoparticles resulted in a significant 96% reduction after 135 min at ambient temperature (25 °C) and a pH value of 9. Additionally, MgFe2O4 nanoparticles exhibited potent antibacterial activity against E. coli and S. aureus in a dose dependent manner with maximum utilized concentration of 30 µg/ml. Specifically, MgFe2O4 nanoparticles demonstrated substantial antibacterial activity via disk diffusion and microbroth dilution tests with zones of inhibition and minimum inhibitory concentrations (MIC) for E. coli (26.0 mm, 1.25 µg/ml) and S. aureus (23.0 mm, 2.5 µg/ml), respectively. Moreover, 10.0 µg/ml of MgFe2O4 nanoparticles elicited marked percent reduction in biofilm formation by E. coli (89%) followed by S. aureus (78.5%) after treatment. In conclusion, MgFe2O4 nanoparticles demonstrated efficient dye removal capabilities along with significant antimicrobial and antibiofilm activity against gram-positive and gram-negative bacterial strains suggesting their potential as promising antimicrobial and detoxifying agents.

Antibacterial, antibiofilm, and chemical profiles of Ammi visnaga L. and Foeniculum vulgare mill. Essential oils, and ADMET, molecular docking investigation of essential oils major components.

This study determined chemical profiles, antibacterial and antibiofilm activities of the essential oils (EOs) obtained by A. visnaga aerial parts and F. vulgare fruits. Butanoic acid, 2-methyl-, 3-methylbutyl ester (38.8%), linalyl propionate (34.7%) and limonene (8.5%) resulted as main constituents of A. visnaga EO. In F. vulgare EO trans-anethole (76.9%) and fenchone (14.1%) resulted as main components. The two EOs were active against five bacterial strains (Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus) at different degrees. The MIC values ranged from 5 ± 2 to 10 ± 2 µL/mL except for S. aureus (MIC >20 µL/mL). EOs exhibited inhibitory effect on the formation of biofilm up to 53.56 and 48.04% against E. coli and A. baumannii, respectively and activity against bacterial metabolism against A. baumannii and E. coli, with biofilm-inhibition ranging from 61.73 to 73.55%. The binding affinity of the identified components was estimated by docking them into the binding site of S. aureus gyrase (PDB code 2XCT) and S. aureus tyrosyl-tRNA synthetase (PDB code 1JIJ). trans-Anethole and butanoic acid, 2-methyl-, 3-methylbutyl ester showed relatively moderate binding interactions with the amino acid residues of S. aureus tyrosyl-tRNA synthetase. In addition, almost all predicted compounds possess good pharmacokinetic properties with no toxicity, being inactive for cytotoxicity, carcinogenicity, hepatotoxicity, mutagenicity and immunotoxicity parameters. The results encourage the use of these EOs as natural antibacterial agents in food and pharmaceutical industries.

Chemical Composition and Phytotoxic and Antibiofilm Activity of the Essential Oils of two Moroccan Retama species.

This study reports chemical composition, phytotoxic and antibiofilm activities of essential oils (EOs) of R. dasycarpa and R. sphaerocarpa from Morocco. EOs were analyzed by GC/MS and their phytotoxicities were evaluated against germination and seedling growth of Lolium multiflorum, Sinapis alba and Raphanus sativus. The antimicrobial and anti-biofilm activities were studied against Gram-negative (Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii) and Gram-positive bacteria (Staphylococcus aureus and Listeria monocytogenes). Both EOs were abundant in oxygenated monoterpenes (40.01% and 23.57%, respectively). Carvacrol is the predominant component in R. dasycarpa EO (17.80%), and it also represents an appreciable amount in R. sphaerocarpa (8.96%). R. sphaerocarpa showed total inhibition at high doses against all seeds. S. alba seeds were the most sensitive to all EOs. Minimum inhibitory concentration (MIC) values indicated significant inhibition for R. sphaerocarpa, between 24 and 30 µg/mL, with a remarkable antibacterial potential and biofilm formation inhibition. R. sphaerocarpa EO showed significant biofilm inhibition with variable efficacy depending on the strain and concentration, except for S. aureus. R. dasycarpa exhibited activity against all bacterial strains and effect on metabolism with activity also on mature biofilms. Results suggest that Retama EOs could have potential applications in the fields of food and health.

Antifungal and antibiofilm effects of probiotic Lactobacillus salivarius, zinc nanoparticles, and zinc nanocomposites against Candida albicans from Nile tilapia (Oreochromis niloticus), water and humans.

Introduction: Candida albicans (C. albicans) can form biofilms; a critical virulence factor that provides effective protection from commercial antifungals and contributes to public health issues. The development of new antifungal therapies, particularly those targeting biofilms, is imperative. Thus, this study was conducted to investigate the antifungal and antibiofilm effects of Lactobacillus salivarius (L. salivarius), zinc nanoparticles (ZnNPs) and nanocomposites (ZnNCs) on C. albicans isolates from Nile tilapia, fish wash water and human fish sellers in Sharkia Governorate, Egypt. Methods: A cross-sectional study collected 300 samples from tilapia, fish wash water, and fish sellers (100 each). Probiotic L. salivarius was immobilized with ZnNPs to synthesize ZnNCs. The study assessed the antifungal and antibiofilm activities of ZnNPs, L. salivarius, and ZnNCs compared to amphotericin (AMB). Results: Candida spp. were detected in 38 samples, which included C. albicans (42.1%), C. glabrata (26.3%), C. krusei (21.1%), and C. parapsilosis (10.5%). A total of 62.5% of the isolates were resistant to at least one antifungal agent, with the highest resistance to nystatin (62.5%). However, 75% of the isolates were highly susceptible to AMB. All C. albicans isolates exhibited biofilm-forming capabilities, with 4 (25%) isolates showing strong biofilm formation. At least one virulence-associated gene (RAS1, HWP1, ALS3, or SAP4) was identified among the C. albicans isolates. Probiotics L. salivarius, ZnNPs, and ZnNCs displayed antibiofilm and antifungal effects against C. albicans, with ZnNCs showing significantly higher inhibitory activity. ZnNCs, with a minimum inhibitory concentration (MIC) of 10 µg/mL, completely reduced C. albicans biofilm gene expression. Additionally, scanning electron microscopy images of C. albicans biofilms treated with ZnNCs revealed asymmetric, wrinkled surfaces, cell deformations, and reduced cell numbers. Conclusion: This study identified virulent, resistant C. albicans isolates with strong biofilm-forming abilities in tilapia, water, and humans, that pose significant risks to public health and food safety.

Pseudomonas otitidis-mediated synthesis of silver nanoparticles: characterization, antimicrobial and antibiofilm potential.

This study explores the eco-friendly synthesis of silver nanoparticles (AgNPs) using soil bacteria, Pseudomonas otitidis. The bio-synthesized AgNPs were characterized using various techniques, including UV-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). UV-visible spectroscopy revealed a distinct broad absorption band in the range of 443 nm, indicating the reduction of silver nitrate to AgNPs. XRD analysis provided evidence of the crystalline nature of the particles, with sharp peaks confirming their crystallinity and an average size of 82.76 nm. FTIR spectroscopy identified extracellular protein compounds as capping agents. SEM examination revealed spherical agglomeration of the crystalline AgNPs. The antimicrobial assay by a disc diffusion method, minimum inhibitory concentration, and minimum bactericidal concentration testing revealed that the biosynthesized AgNPs showed moderate antibacterial activity against both pathogenic Gram-negative (Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii) and Gram-positive (Bacillus cereus, Staphylococcus aureus, and Streptococcus mutans) bacterial strains. Furthermore, the AgNPs significantly disrupted the biofilm of P. aeruginosa, as confirmed by crystal violet assay and fluorescent microscopy. Overall, this study underscores the potential of microbial-synthesized nanoparticles in biomedical applications, particularly in combating pathogenic bacteria, offering a promising avenue for future research and development.

The influence of the chlorine atom on the biological activity of 2'-hydroxychalcone in relation to the lipid phase of biological membranes - Anticancer and antimicrobial activity.

The study investigates the effect of the presence of a chlorine atom in the 2'-hydroxychalcone molecule on its interaction with model lipid membranes, in order to discern its potential pharmacological activity. Five chlorine derivatives of 2'-hydroxychalcone were synthesized and evaluated against liposomes composed of POPC and enriched with cationic (DOTAP) or anionic (POPG) lipids. The physicochemical properties of the compounds were initially simulated using SwissAdame software, revealing high lipophilicity (ilogP values: 2.79-2.90). The dynamic light scattering analysis of liposomes showed that chloro chalcones induce minor changes in the diameter of liposomes of different surface charges. Fluorescence quenching assays with a TMA-DPH probe demonstrated the strong ability of the compounds to interact with the lipid bilayer, with varying quenching capacities based on chlorine atom position. FTIR studies indicated alterations in carbonyl, phosphate, and choline groups, suggesting a transition area localization rather than deep penetration into the hydrocarbon chains. Additionally, dipole potential reduction was observed in POPC and POPC-POPG membranes, particularly pronounced by derivatives with a chlorine atom in the B ring. Antibacterial and antibiofilm assays revealed enhanced activity of derivatives with a chlorine atom compared to 2'-hydroxychalcone, especially against Gram-positive bacteria. The MIC and MBIC50 values showed increased efficacy in the presence of chlorine with 3'-5'-dichloro-2'-hydroxychalcone demonstrating optimal antimicrobial and antibiofilm activity. Furthermore, antiproliferative assays against breast cancer cell lines indicated higher activity of B-ring chlorine derivatives, particularly against MDA-MB-231 cells. In general, the presence of a chlorine atom in 2'-hydroxychalcone improves its pharmacological potential, with derivatives showing improved antimicrobial, antibiofilm, and antiproliferative activities, especially against aggressive breast cancer cell lines. These findings underscore the importance of molecular structure in modulating biological activity and highlight chalcones with a chlorine as promising candidates for further drug development studies.

Silibinin-loaded chitosan-capped silver nanoparticles exhibit potent antimicrobial, antibiofilm, and anti-inflammatory activity against drug-resistant nosocomial pathogens.

Nanoparticles capped with natural products can be a cost-effective alternative to treat drug-resistant nosocomial infections. Therefore, silibinin-loaded chitosan-capped silver nanoparticles (S-C@AgNPs) were synthesized to evaluate their antimicrobial and anti-inflammatory potential. The S-C@AgNPs plasmon peak was found at 430 nm and had a particle size distribution of about 130 nm with an average hydrodynamic diameter of 101.37 nm. The Scanning Electron Microscopy images showed the presence of sphere-shaped homogeneous nanoparticles. The Fourier Transform Infrared Spectroscopy analysis confirmed the loading of silibinin and chitosan on the AgNPs surface. The minimum inhibitory concentration of the S-C@AgNPs was reported between 3.12 µg/ml to 12.5 µg/ml and a minimum bactericidal concentration between 6.25 µg/ml to 25 µg/ml against drug-resistant nosocomial pathogens. Moreover, concentration-dependent significant inhibition of the biofilm formation was reported against P. aeruginosa (70.21%) and K. pneumoniae (71.02%) at 30 µg/ml, and the highest destruction of preformed biofilm was observed at 100 µg/ml against P. aeruginosa (89.74%) and K. pneumoniae (77.65%) as compared to individual bacterial control. Additionally, the fluorescence live/dead assay for bacterial biofilm confirmed that 100 µg/ml effectively inhibits the biofilm formed by these pathogens. S-C@AgNPs also showed anti-inflammatory activity, which is evident by the significant decrease in the proinflammatory cytokines and chemokines level in THP1 cells treated with LPS. This study concluded that S-C@AgNPs have potent antimicrobial, antibiofilm, and anti-inflammatory properties and could be a potential option for treating drug resistant nosocomial infections.

Exploring the frontiers of therapeutic breadth of antifungal peptides: A new avenue in antifungal drugs.

The growing prevalence of fungal infections alongside rising resistance to antifungal drugs poses a significant challenge to public health safety. At the close of the 2000s, major pharmaceutical firms began to scale back on antimicrobial research due to repeated setbacks and diminished economic gains, leaving only smaller companies and research labs to pursue new antifungal solutions. Among various natural sources explored for novel antifungal compounds, antifungal peptides (AFPs) emerge as particularly promising. Despite their potential, AFPs receive less focus than their antibacterial counterparts. These peptides have been sourced extensively from nature, including plants, animals, insects, and especially bacteria and fungi. Furthermore, with advancements in recombinant biotechnology and computational biology, AFPs can also be synthesized in lab settings, facilitating peptide production. AFPs are noted for their wide-ranging efficacy, in vitro and in vivo safety, and ability to combat biofilms. They are distinguished by their high specificity, minimal toxicity to cells, and reduced likelihood of resistance development. This review aims to comprehensively cover AFPs, including their sources-both natural and synthetic-their antifungal and biofilm-fighting capabilities in laboratory and real-world settings, their action mechanisms, and the current status of AFP research. ONE-SENTENCE SUMMARY: This comprehensive review of AFPs will be helpful for further research in antifungal research.

Electron Beam-Supported Fabrication of Biocompatible Silver/iota-Carrageenan for Wound Healing Application.

Silver nanoparticles (AgNPs) are a potent antibacterial agent, especially when used to treat bacteria that are multidrug resistant. However, it is challenging to eliminate the hazardous reducing agents that remain in AgNPs produced by the conventional chemical reduction process. To overcome these challenges, the presented research demonstrates the fabrication of AgNPs using iota-carrageenan (ι-carra) as a carbohydrate polymer using electron beam (EB) irradiation. Well-characterized ι-carra@AgNPs have a face-centered cubic (FCC) structure with spherical morphology and an average size of 26 nm. Herein we explored the approach for fabricating ι-carra@AgNPs that is suitable for scaling up the production of nanoparticles that exhibit excellent water stability. Further, the optimized ι-carra@AgNPs exhibited considerable antibacterial activity of 40% and 30% inhibition when tested with Gram-negative Escherichia coli ATCC 43895 and Gram-positive Staphylococcus aureus (S. aureus) (ATCC 6538), respectively, and low cytotoxicity at 10-50 µg/mL. To establish the potential biomedical application, as proof of the concept, the ι-carra@AgNPs showed significant antibiofilm activity at 20 µg/mL and also showed 95% wound healing abilities at 50 µg/mL compared to the nontreated control groups. Electron beam assisted ι-carra@AgNPs showed significant beneficial effects against specific bacterial strains and may provide a guide for the development of new antibacterial materials for wound dressing for large-scale production for biomedical applications.

Evaluating the antimicrobial and anti-biofilm activity of three synthetic antimicrobial Citropin analogs and their ability to fight against Staphylococcus aureus and Staphylococcus pseudintermedius.

AIMS: We developed three new analogs of the antimicrobial peptide (AMP) Citropin 1.1: DAN-1-13, AJP-1-1, and HHX-2-28, and tested their potential antimicrobial and antibiofilm activities against Staphylococcus aureus and S. pseudintermedius. Potential cytotoxic or hemolytic effects were determined using cultured human keratinocytes and erythrocytes to determine their safety. METHODS AND RESULTS: To assess the antimicrobial activity of each compound, minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were determined against methicillin-resistant and methicillin-susceptible strains of S. aureus and S. pseudintermedius. Activity against newly formed and mature biofilms was determined in two clinical isolates using spectrophotometry and scanning electron microscopy (SEM). All three compounds exhibited antimicrobial and bactericidal activity against all studied S. aureus and S. pseudintermedius strains, with MICs ranging from 4-32 µg ml-1 and MBCs ranging from 8-128 µg ml-1. Subinhibitory concentrations of all compounds also showed ant-biofilm activity in the two tested isolates. All compounds exhibited limited cytotoxic and hemolytic activity. CONCLUSIONS: Novel analogs of Citropin 1.1 exhibit antimicrobial and bactericidal activities against S. aureus and S. pseudintermedius isolates and inhibit the biofilm formation of these bacteria.

Characterization of antibiofilm compound from marine sponge Stylissa carteri.

The fouling phenomenon grabbed global attention and caused huge economic losses specifically in marine-related industries. Sessile behavior exposed the sponge to the risk of fouling. However, their bodies remained free from foulers, which were attributed to the chemical defense system. The objectives of this study were to determine the antibiofilm activity of the marine sponge, Stylissa carteri, and to characterize the isolated compound involved. The antibiofilm activity of S. carteri methanolic crude extract (MCE) and fractions was tested against biofilm-producing bacteria, Pseudomonas aeruginosa, using two different modes of crystal violet biofilm assays: preventive and detachment. Besides that, the disc-diffusion test was conducted to screen the antibacterial activity against gram-positive and gram-negative bacteria while a cytotoxicity assay was conducted on the HepG2 cell line. Bioassay-guided fractionation was carried out using vacuum liquid chromatography (VLC) and solid phase extraction using a C18 Sep-Pak Cartridge. The crystal compound was isolated and characterized through thin-layer chromatography (TLC), Fourier transform infrared (FTIR) spectroscopy, liquid chromatography-mass spectrometry (LCMS), and nuclear magnetic resonance (NMR) spectroscopy. The S. carteri MCE showed a promising result with a half-maximal inhibitory concentration (IC50) of 20.22 µg/mL in the preventive assay, while no IC50 was determined in the detachment assay since all inhibitions < 50%. The S. carteri MCE exhibited broad-spectrum antibacterial activity and displayed a non-cytotoxic effect. Fraction 4 from MCE of S. carteri (IC50 = 2.40 µg/mL) reduced the biofilm in the preventive assay at all concentrations and exhibited no antibacterial activity indicating the independence of antibiofilm from antibacterial properties. Based on the data obtained, an alkaloid named debromohymenialdisine (DBH) was identified from Fraction 4 of S. carteri MCE. In conclusion, S. carteri was able to reduce the establishment of the biofilm formed by P. aeruginosa and could serve as a prominent source of natural antifouling agents.

In Vitro and In Silico Characterization of N-Formylated Two-Peptide Bacteriocin from Enterococcus faecalis CAUM157 with Anti-Listeria Activity.

Enterococcus faecalis CAUM157 (KACC 81148BP), a Gram-positive bacteria isolated from raw cow's milk, was studied for its bacteriocin production. The antimicrobial activity of CAUM157 was attributed to a two-peptide class IIb bacteriocin with potent activity against food-borne pathogen Listeria monocytogenes and periodontal disease-causing pathogens (Prevotella intermedia KCTC 15693 T and Fusobacterium nucleatum KCTC 2488 T). M157 bacteriocins exhibit high temperature and pH stability and resist hydrolytic enzyme degradation and detergent denaturation, potentially due to their structural conformation. Based on amino acid sequence, M157A and M157B were predicted to be 5.176 kDa and 5.182 kDa in size, respectively. However, purified bacteriocins and chemically synthesized N-formylated M157 peptides both showed 5.204 kDa (M157A) and 5.209 kDa (M157B) molecular mass, confirming the formylation of the N-terminal methionine of both peptides produced by strain CAUM157. Furthermore, the strain demonstrated favorable growth and fermentation with minimal bacteriocin production when cultured in whey-based media, whereas a 1.0% tryptone or soytone supplementation resulted in higher bacteriocin production. Although Ent. faecalis CAUM157 innately harbors genes for virulence factors and antimicrobial resistance (e.g., tetracycline and erythromycin), its bacteriocin production is valuable in circumventing the need for live microorganisms, particularly in food applications for pathogen control.

Antimicrobial and antibiofilm activities of Brazilian organic honey against oral microorganisms.

OBJECTIVE: To evaluate the antimicrobial activity of Brazilian honeys against oral microorganisms. DESIGN: Organic honeys (OH-1 to OH-8) were diluted (%-w/v) and sterilized by filtration. Antimicrobial activity was defined by determining MIC and CBM against oral Streptococcus. The component responsible for the antimicrobial action was defined by a catalase assay. Antibiofilm activity was evaluated against the monospecies biofilm of Streptococcus mutans  (ATCC 700610). RESULTS: OHs showed antimicrobial activity principally OH-1, OH-2, OH-3, and OH-7 with MIC values ​​ranging between 10 and 25%. The mechanism of action occurs mainly by hydrogen peroxide produced by honey enzymes. OH-1, OH-2, and OH-7 showed total biofilm destruction at low concentrations. CONCLUSION: Brazilian honeys have promising antimicrobial and antibiofilm activity with the potential to control oral microbiota.

Phytochemical Characterization and Biological Activities of Essential Oil from Satureja montana L., a Medicinal Plant Grown under the Influence of Fertilization and Planting Dates.

The rising demand for safe plant compounds and herbal products that contribute positively to human health is in line with current market trends. Plants belonging to the Satureja genus, particularly the aromatic medicinal S. montana L. from the Lamiaceae family, are well suited to these trends as they serve as pharmaceutical raw materials. This research aimed to assess the influence of sowing date and fertilization doses, as well as their interaction, on the fresh weight, essential oil content, and composition of S. montana. Experimental cultivation involved varying nitrogen and phosphorus levels. The second cut had the highest fresh weight and oil production compared to the first cut. The highest total plant biomass was achieved with autumn sowing and fertilization at 55 kg N/ha and 37 kg P/ha, whereas Spring sowing exhibited higher essential oil production, with the maximum oil % with 74 kg P/ha and oil yield after applying 55 kg N/ha and 74 kg P/ha. The GC-MS analysis revealed that carvacrol was the predominant compound, with it being recommended to grow S. montana in Spring at doses of 55 kg N/ha and 74 kg P/ha for the superior oil yield. Additionally, S. montana essential oil demonstrated notable biological and antimicrobial activity, positioning it as a potential alternative to chemical food preservatives.