Mechanism Of Antimicrobial Action Research Articles

A Comprehensive Review on the Antibacterial, Antifungal, Antiviral, and Antiparasitic Potential of Silybin

Silybin, a flavonolignan extracted from the seeds of the plant species Silybum marianum (L.) Gaertn., has a variety of pharmacological activities, including antimicrobial activity against several microorganisms of clinical interest. This review analyzes the existing studies on silybin’s antimicrobial activity and possible mechanisms of action. Silybin has been shown to inhibit the growth of Gram-positive and Gram-negative bacteria, as well as some fungi, viruses, and protozoa. In general, possible mechanisms of antimicrobial action include the inhibition of efflux pumps, prevention of biofilm formation, reduction of the expression of virulence factors, induction of apoptosis-like effects, and plasma membrane damage, as well as the inhibition of nucleic acid and protein synthesis. Silybin has been shown to have synergistic effects when combined with conventional antibiotics against both drug-sensitive and drug-resistant microorganisms. However, the low bioavailability observed for this flavonolignan has been a challenge to its clinical use. In this context, nanotechnology has been used to increase silybin’s bioavailability while enhancing its antimicrobial activity. Furthermore, certain structural modifications have been able to enhance its antimicrobial activity in comparison to that of the natural molecule. Overall, this review provides insights into the scientific understanding of the mechanism of action of silybin and its desired properties for the effective treatment of infections.

Antibacterial and therapeutic potential of historic deposits of silesian healing clay – terra sigillataSilesiaca

Ethnopharmacological relevanceThe increasing evolution of pathogen resistance is a global problem that requires novel solutions. Recently, an increased interest in ethnomedicinal sources can be observed in the derivation of new medicines. The return to traditional medicinal formulations handed down for generations is being followed, but it is necessary to revise them again, taking into account the generally accepted research protocol. Aim of the studyWe aimed to evaluate the antimicrobial potential of historical deposits of Silesian healing clay (SHC), used in ethnomedicine against Gram-positive bacteria and to assess their biological activity using a primary dermal fibroblast line (NHDF) and a model monocyte line (THP1). Materials and methodsInformation on medicinal clay deposits that occur in Silesia and are traditionally used in ethnomedicine or ancient medicine and known as terra sigillata Silesiaca or SHC, was selected on available source materials and old prints and maps from the archives of the Polish Geological Institute (Wrocław, Poland). Subsequently, their places of occurrence were identified and traced in the field by taking three deposits from the Silesia territory: Upper Silesia (D1), Opole Silesia (D2), and Lower Silesian (D3) Voivodeships for analysis. Their basic parameters and antimicrobial efficacy against pathogenic bacteria, Gram-positive streptococci and staphylococci, including methicillin-resistant strains, were examined. The study evaluated the effects of clays on growth and vitality using a primary dermal fibroblast line (NHDF) and a monocytic line (THP1). Studies were performed on a cell culture model to determine the effects on tissue regeneration (fibroblasts) and anti-inflammatory effects (monocytes). The study attempted to identify the mechanism of antimicrobial action, especially the textural characteristics and geochemical composition, as well as the environmental reaction (pH). ResultsSHCs were classified into the following textural classes: clay loam (D1), clay (D2), and sand (D3). The tested deposits have antimicrobial properties that reduce the bacterial population (104 CFU) compared to the control (108 CFU). The antimicrobial effect depends on the type of clay and the species or strain of bacteria used. In-house studies clearly showed that Staphylococcus aureus Pcm 2054 and Staphylococcus epidermidis MRSE ATCC 2538 cells were completely adsorbed by clay minerals from clay D3.13. Furthermore, 10% leachates also showed an antimicrobial effect, as a reduction in bacterial populations was observed ranging from 91 to 100%. The results showed stimulation of fibroblast culture proliferation and inhibition of the growth of inflammatory cells (monocytes). ConclusionSHCs tested have antimicrobial potential, in particular D2.7, D2.11, and D3.13. The D3.13 deposit had a bactericidal effect against the staphylococci tested. Aqueous solutions of clays also showed bacteriostatic effect. The results obtained in cell culture model tests indicate properties that modulate the healing process – stimulation of fibroblast growth (NHDF line) and inhibition of monocyte growth (THP1 line).

Abietane diterpenoid salvipisone: Structure elucidation, conformational analysis, and antimicrobial activity

Salvipisone, an abietane diterpenoid, was isolated from the roots of Salvia aethiopis L. using a combination of chromatographic separation techniques. Its structure was elucidated employing a variety of spectroscopic methods, including ultraviolet (UV), infrared (IR), 1D and 2D nuclear magnetic resonance (NMR), and mass spectrometry. A comprehensive analysis of experimental 1D and 2D NMR data, incorporating 1H iterative full spin analysis and higher-order multiplet simulation, revealed discrepancies with previously reported NMR data for this compound. Detailed examination of the 1H NMR spectrum's spin-spin coupling structure provided insights into the relative populations of the three staggered conformers around the C12–C13 bond at room temperature. The conformer populations were determined using the relationship between the experimental values for vicinal coupling constants and the estimated ones for the preferred staggered conformers, yielding a ratio of approx. 80:4:16 for anti, gauche, and gauche′-conformers, respectively. Possible reasons for the observed unevenly populated staggered conformers were also discussed. The antimicrobial activity of salvipisone was evaluated using in vitro and in silico methods. In vitro antimicrobial assays demonstrated that salvipisone exhibited the highest inhibitory effect against Staphylococcus aureus ATCC and Enterococcus faecalis ATCC (MIC = 3.125 μg/mL), followed by Bacillus subtilis ATCC (MIC = 6.25 μg/mL). In contrast, concentrations above 100 μg/mL were necessary to inhibit Escherichia coli ATCC and Klebsiella pneumoniae ATCC. In silico studies suggested that salvipisone, particularly its keto form, has significant potential for inhibiting the enzyme gyrase, highlighting its mechanism of antimicrobial action. Our findings highlight the promising antimicrobial and inhibitory properties of salvipisone, particularly against Gram-positive bacteria such as S. aureus.

CycP: A Novel Self-Assembled Vesicle-Forming Cyclic Antimicrobial Peptide to Control Drug-Resistant S. aureus.

Antimicrobial peptides (AMPs) are considered a promising alternative to conventional antibiotics to fight against the rapid evolution of antibiotic resistance. Other than their potent antimicrobial properties, AMP-based vesicles can be used as efficient drug-delivery vehicles. In the present study, we synthesized and characterized a new cyclic AMP, consisting of all-hydrophobic cores with antimicrobial activity against S. aureus. Interestingly, CycP undergoes supramolecular self-assembly, and self-assembled CycP (sCycP) vesicles are characterized under an electron microscope; however, these vesicles do not display antimicrobial activity. Next, sCycP vesicles are used in combination with SXT (sulfamethoxazole-trimethoprim) vesicles to check the drug loading and delivery capacity of sCycP vesicles to bacterial cell membranes. Interestingly, sCycP vesicles showed synergistic action with SXT vesicles and resulted in a significant reduction in MIC against S. aureus. Further, electron microscopy confirmed the membrane-specific killing mechanism of SXT-loaded sCycP vesicles. Additionally, CycP showed high binding affinities with the β-lactamase of S. aureus, which was one of its possible antimicrobial mechanisms of action. Overall, the results suggested that CycP is a novel self-assembled dual-action cyclic AMP with non-cytotoxic properties that can be used alone as an AMP or a self-assembled drug delivery vehicle for antibiotics to combat S. aureus infections.

Sustainable Solution to Antibiotic Resistance: Pavetta indica-Based Nanomedicine

The escalating global health crisis, characterized by the emergence of antimicrobial-resistant pathogens, necessitates innovative strategies. This study explores the potential of Pavetta indica, a previously underutilized plant, as a multifaceted resource for addressing this critical challenge. A comprehensive phytochemical investigation unveiled a rich repertoire of bioactive compounds within P. indica, including essential metabolites Moisture (9.14%), Crude Protein (10.93%), and Crude Fiber (15.46%). Additionally, significant levels of Calcium, Phosphorus, and Ether Extract were identified, suggesting its potential contribution to a balanced diet and a diverse array of secondary metabolites identified through GC-MS analysis identified diverse bioactive compounds including Dodecanoic acid, Lupeol, and β-D-Glucopyranose among others, highlighting its potential health benefits and paving the way for further research on specific bioactivities. P. indica extract exhibited concentration-dependent ABTS and DPPH scavenging activities, comparable to ascorbic acid. This underscores its potential as a natural antioxidant source to combat oxidative stress-related diseases. Leveraging the bio-reducing capabilities of P. indica extract, we embarked on the green synthesis of silver nanoparticles. P. indica extract successfully synthesized silver nanoparticles, confirmed by UV-Vis spectroscopy (SPR band at 420 nm) and TEM (spherical particles, 25-50 nm). These nanoparticles showed potent antimicrobial activity against Bacillus subtilis, E. coli, and Pseudomonas aeruginosa, comparable to Gentamicin. The synthesized silver nanoparticles demonstrated concentration-dependent antifungal activity against Candida albicans, Aspergillus fumigatus, and Sporothrix schenckii, suggesting their potential as effective antifungal agents. Our findings underscore the significance of exploring underutilized plant resources for developing innovative solutions to pressing global health challenges. By integrating phytochemistry, nanotechnology, and microbiology, this research offers a promising approach to combating antimicrobial resistance. The study's outcomes lay the groundwork for future investigations into the underlying mechanisms of antimicrobial action, optimization of nanoparticle properties, and preclinical evaluation of their therapeutic efficacy.

A review of the synthesis and application of azo dyes and metal complexes for emerging antimicrobial therapies

Antimicrobial resistance presents a formidable challenge to contemporary medicine, necessitating innovative therapeutic solutions. Azo dyes and their metal complexes have emerged as promising candidates due to their notable antimicrobial properties. This review comprehensively examines the synthesis and application of azo dyes and metal complexes for emerging antimicrobial therapies. Through various synthetic strategies and metallation, the chemical structure of azo derivatives allows for modifications that enhance their antimicrobial efficacy, making them promising candidates for pharmaceutical development against microbial infections. The study provides a comprehensive understanding of the mechanisms of antimicrobial action, including DNA intercalation, enzyme inhibition, membrane disruption, and reactive oxygen species generation. The role of metal ions is particularly significant, enhancing structural stability, reactivity, and the ability to target microbial enzymes effectively. Chelation effects, such as reduced polarity and increased lipophilicity, facilitate the penetration of microbial cell membranes and the disruption of enzyme activity. The review highlights novel azo-metal complexes’ significant antifungal and antibacterial activities, particularly their efficacy against pathogens such as Mycobacterium tuberculosis. The importance of structure-activity relationships is detailed, showing how specific functional groups and metal ions influence antimicrobial efficacy. Additionally, their potential sensing ability to detect and identify microorganisms highlights the multifaceted role of azo dye derivatives in infection management.

The antioxidant and antimicrobial activity of ethanolic extract in roots, stems, and leaves of three commercial Cymbopogon species

BackgroundCymbopogon is a member of the family Poaceae and has been explored for its phytochemicals and bioactivities. Although the antimicrobial activities of Cymbopogon spp. extracts have been extensively studied, comprehensive analyses are required to identify promising compounds for the treatment of antimicrobial resistance. Therefore, this study investigated the antioxidant and antimicrobial properties of Cymbopogon spp. ethanolic extracts in every single organ.MethodsEthanolic extracts were obtained from three Indonesian commercial species of Cymbopogon spp., namely Cymbopogon citratus (L.) Rendle, Cymbopogon nardus (DC.) Spatf., and Cymbopogon winterianus Jowitt. The leaf, stem, and root extracts were evaluated via metabolite profiling using gas chromatography-mass spectrometry (GC–MS). In silico and in vitro analyses were used to evaluate the antioxidant and antimicrobial properties of the Cymbopogon spp. ethanolic extracts. In addition, bioactivity was measured using cytotoxicity assays. Antioxidant assays were performed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2-azino-bis [3-ethylbenzothiazoline-6-sulfonic acid (ABTS) to determine toxicity to Huh7it-1 cells using a tetrazolium bromide (MTT) assay. Finally, the antimicrobial activity of these extracts was evaluated against Candida albicans, Bacillus subtilis, Staphylococcus aureus, and Escherichia coli using a well diffusion assay.ResultsGC–MS analysis revealed 53 metabolites. Of these, 2,5-bis(1,1-dimethylethyl)- phenol (27.87%), alpha-cadinol (26.76%), and 1,2-dimethoxy-4-(1-propenyl)-benzene (20.56%) were the predominant compounds. C. winterianus and C. nardus leaves exhibited the highest antioxidant activity against DPPH and ABTS, respectively. Contrastingly, the MTT assay showed low cytotoxicity. C. nardus leaf extract exhibited the highest antimicrobial activity against E. coli and S. aureus, whereas C. winterianus stem extract showed the highest activity against B. substilis. Furthermore, computational pathway analysis predicted that antimicrobial activity mechanisms were related to antioxidant activity.ConclusionsThese findings demonstrate that the leaves had strong antioxidant activity, whereas both the leaves and stems showed great antimicrobial activity. Furthermore, all Cymbopogon spp. ethanolic extracts showed low toxicity. These findings provide a foundation for future studies that assess the clinical safety of Cymbopogon spp. as novel drug candidates.

Mechanism of antibacterial phytoconstituents: an updated review.

The increase of multiple drug resistance bacteria significantly diminishes the effectiveness of antibiotic armory and subsequently exaggerates the level of therapeutic failure. Phytoconstituents are exceptional substitutes for resistance-modifying vehicles. The plants appear to be a deep well for the discovery of novel antibacterial compounds. This is owing to the numerous enticing characteristics of plants, they are easily accessible and inexpensive, extracts or chemicals derived from plants typically have significant levels of action against infections, and they rarely cause serious adverse effects. The enormous selection of phytochemicals offers very distinct chemical structures that may provide both novel mechanisms of antimicrobial activity and deliver us with different targets in the interior of the bacterial cell. They can directly affect bacteria or act together with the crucial events of pathogenicity, in this manner decreasing the aptitude of bacteria to create resistance. Abundant phytoconstituents demonstrate various mechanisms of action toward multi drug resistance bacteria. Overall, this comprehensive review will provide insights into the potential of phytoconstituents as alternative treatments for bacterial infections, particularly those caused by multi drug resistance strains. By examining the current state of research in this area, the review will shed light on potential future directions for the development of new antimicrobial therapies.

Exploring the efficacy of pulsed electric fields (PEF) in microbial inactivation during food processing: A deep dive into the microbial cellular and molecular mechanisms

Pulsed electric field (PEF) is a food processing technology based on the phenomenon of electroporation for the inactivation of microorganisms with main advantage the minimal effect on the quality (nutritional, functional, and sensorial) characteristics of the food products. Despite the plethora of research literature on PEF-processed food safety, PEF's industrial application as an alternative of classical pasteurization is limited and mainly at industrial level is focused on high acid-liquid food products. Thus, the thorough assessment of the antimicrobial efficiency of PEF, coupled with the meticulous identification of key microbial resistance mechanisms is scientifically imperative. These efforts are essential for refining the process and exploring potential enhancements through synergistic integration and combination with other methods or/and hurdles. On this basis this manuscript aims to critically review and summarise: a) the antimicrobial mechanism of action, b) the microbial inactivation efficiency, and c) the effect of PEF at a microbial genomic/transcriptomic level. Industrial applicationEvaluating the effectiveness of inactivation and understanding the underlying resistance mechanisms can help on strategies to optimize PEF-mediated decontamination practices, and thereby enhancing the overall process efficiency.

Glycolysis and Automated Plaque Regrowth Method for Evaluation of Antimicrobial Performance.

This study explored the potential of a new in vitro method in evaluating antiplaque benefits from five sets of antimicrobial systems including cetylpyridinium chloride (CPC), stannous fluoride (SnF2), Listerine essential oil mouthwashes (+/- alcohol), zinc chloride (ZnCl2), and sodium fluoride. (NaF). Gingival dental plaque was collected and propagated using sterilized tryptic soy broth and sucrose, and then allocated into separate glycolysis and regrowth recipes for antiplaque evaluations. Glycolysis measurements (in duplicate) were recorded via pH microelectrode on plaque-treatment samples thermomixed (1200 rpm, 37 °C) for 4 h. For plaque regrowth, optical densities (in duplicate) were automatically collected on plaque-treatment samples using a microplate reader (linear shaking, 37 °C) from baseline to 4 h. Calculations of percent change in pH and optical density were performed and analyzed for each set of antimicrobial treatment groups. Statistical analysis (one-way ANOVA, Student-Newman-Keuls stepwise comparison tests) revealed dose responses and significant differences (p < 0.05) among treatment groups, including between negative and clinically relevant positive controls. This lab method produces results consistent with published clinical observations. This glycolysis and plaque growth method is sensitive to antimicrobial mechanisms of action, and may offer a convenient and clinically relevant screening tool in the evaluation of putative antimicrobial agents and formulations.

Comparison of Antimicrobial Properties of Graphene Oxide-Based Materials, Carbon Dots, and Their Combinations Deposited on Cotton Fabrics.

The rise in the antibiotic resistance of bacteria has increased scientific interest in the study of materials with unique mechanisms of antimicrobial action. This paper presents the results of studies on the antimicrobial activity of carbon materials and textiles decorated with them. A comparative analysis of the bactericidal and fungicidal activities of graphene oxide, electrochemically exfoliated multigraphene, carbon dots, and their combinations was performed. Microbiological studies on reference strains of E. coli, S. aureus, and C. albicans showed that graphene oxide inhibited growth with up to 98% efficiency. Electrochemically exfoliated multigraphene was less effective (up to 40%). This study found no significant antimicrobial activity of carbon dots and the combination of carbon dots with graphene oxide significantly weakened their effectiveness. However, the combination of electrochemically exfoliated multigraphene and carbon dots exhibits a synergistic effect (up to 76%). A study on the antimicrobial activity of decorated cotton textiles demonstrated the effectiveness of antimicrobial textiles with graphene oxide, electrochemically exfoliated multigraphene, and a combination of carbon dots with electrochemically exfoliated multigraphene.

Prophylactic efficacy of baicalin and carvacrol against Salmonella Typhimurium biofilm on food and food contact surfaces

This study examines the antimicrobial and antibiofilm effectiveness of baicalin and carvacrol against Salmonella enterica ser. Typhimurium on food contact surfaces and chicken meat. The minimum inhibitory concentrations (MIC) for baicalin and carvacrol were found to be 100 μg/mL and 200 μg/mL, respectively, which aligns with findings from previous studies. The compounds exhibited a concentration-dependent decrease in microbial populations and biofilm formation. When used together, they displayed a remarkable synergistic effect, greatly augmenting their antibacterial activity. The assessment of food quality demonstrated that these treatments have no negative impact on the sensory characteristics of chicken meat. The impact of the structure on biofilms was observed through the use of Field Emission Scanning Electron Microscopy (FE-SEM) and Confocal Laser Scanning Microscopy (CLSM), revealing disrupted biofilm architectures and decreased cell viability. Crucially, RT-PCR analysis revealed a marked downregulation of quorum sensing (luxS), virulence (hilA), and stress response (rpoS) genes, highlighting the multifaceted antimicrobial mechanism of action. This gene-specific suppression suggests a targeted disruption of bacterial communication and virulence pathways, offering insight into the comprehensive antibiofilm strategy. This provides further insight into the molecular mechanisms that contribute to their antibiofilm effects.

“Rich arginine and strong positive charge” antimicrobial protein protamine: From its action on cell membranes to inhibition of bacterial vital functions

Protamine, an antimicrobial protein derived from salmon sperm with a molecular weight of approximately 5 kDa, is composed of 60–70 % arginine and is a highly charged protein. Here, we investigated the mechanism of antimicrobial action of protamine against Cutibacterium acnes (C. acnes) focusing on its rich arginine content and strong positive charge. Especially, we focused on the attribution of dual mechanisms of antimicrobial protein, including membrane disruption or interaction with intracellular components. We first determined the dose-dependent antibacterial activity of protamine against C. acnes. In order to explore the interaction between bacterial membrane and protamine, we analyzed cell morphology, zeta potential, membrane permeability, and the composition of membrane fatty acid. In addition, the localization of protamine in bacteria was observed using fluorescent-labeled protamine. For investigation of the intracellular targets of protamine, bacterial translation was examined using a cell-free translation system. Based on our results, the mechanism of the antimicrobial action of protamine against C. acnes is as follows: 1) electrostatic interactions with the bacterial cell membrane; 2) self-internalization into the bacterial cell by changing the composition of the bacterial membrane; and 3) inhibition of bacterial growth by blocking translation inside the bacteria. However, owing to its strong electric charge, protamine can also interact with DNA, RNA, and other proteins inside the bacteria, and may inhibit various bacterial life processes beyond the translation process.

Providing insight into the mechanism of action of cationic lipidated oligomers using metabolomics.

The increasing resistance of clinically relevant microbes against current commercially available antimicrobials underpins the urgent need for alternative and novel treatment strategies. Cationic lipidated oligomers (CLOs) are innovative alternatives to antimicrobial peptides and have reported antimicrobial potential. An understanding of their antimicrobial mechanism of action is required to rationally design future treatment strategies for CLOs, either in monotherapy or synergistic combinations. In the present study, metabolomics was used to investigate the potential metabolic pathways involved in the mechanisms of antibacterial activity of one CLO, C12-o-(BG-D)-10, which we have previously shown to be effective against methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300. The metabolomes of MRSA ATCC 43300 at 1, 3, and 6 h following treatment with C12-o-(BG-D)-10 (48 µg/mL, i.e., 3× MIC) were compared to those of the untreated controls. Our findings reveal that the studied CLO, C12-o-(BG-D)-10, disorganized the bacterial membrane as the first step toward its antimicrobial effect, as evidenced by marked perturbations in the bacterial membrane lipids and peptidoglycan biosynthesis observed at early time points, i.e., 1 and 3 h. Central carbon metabolism and the biosynthesis of DNA, RNA, and arginine were also vigorously perturbed, mainly at early time points. Moreover, bacterial cells were under osmotic and oxidative stress across all time points, as evident by perturbations of trehalose biosynthesis and pentose phosphate shunt. Overall, this metabolomics study has, for the first time, revealed that the antimicrobial action of C12-o-(BG-D)-10 may potentially stem from the dysregulation of multiple metabolic pathways.IMPORTANCEAntimicrobial resistance poses a significant challenge to healthcare systems worldwide. Novel anti-infective therapeutics are urgently needed to combat drug-resistant microorganisms. Cationic lipidated oligomers (CLOs) show promise as new antibacterial agents against Gram-positive pathogens like methicillin-resistant Staphylococcus aureus (MRSA). Understanding their molecular mechanism(s) of antimicrobial action may help design synergistic CLO treatments along with monotherapy. Here, we describe the first metabolomics study to investigate the killing mechanism(s) of CLOs against MRSA. The results of our study indicate that the CLO, C12-o-(BG-D)-10, had a notable impact on the biosynthesis and organization of the bacterial cell envelope. C12-o-(BG-D)-10 also inhibits arginine, histidine, central carbon metabolism, and trehalose production, adding to its antibacterial characteristics. This work illuminates the unique mechanism of action of C12-o-(BG-D)-10 and opens an avenue to design innovative antibacterial oligomers/polymers for future clinical applications.

Silver Coordination Polymers Driven by Adamantoid Blocks for Advanced Antiviral and Antibacterial Biomaterials.

The development of sustainable biomaterials and surfaces to prevent the accumulation and proliferation of viruses and bacteria is highly demanded in healthcare areas. This study describes the assembly and full characterization of two new bioactive silver(I) coordination polymers (CPs) formulated as [Ag(aca)(μ-PTA)]n·5nH2O (1) and [Ag2(μ-ada)(μ3-PTA)2]n·4nH2O (2). These products were generated by exploiting a heteroleptic approach based on the use of two different adamantoid building blocks, namely 1,3,5-triaza-7-phosphaadamantane (PTA) and 1-adamantanecarboxylic (Haca) or 1,3-adamantanedicarboxylic (H2ada) acids, resulting in the assembly of 1D (1) and 3D (2). Antiviral, antibacterial, and antifungal properties of the obtained compounds were investigated in detail, followed by their incorporation as bioactive dopants (1 wt %) into hybrid biopolymers based on acid-hydrolyzed starch polymer (AHSP). The resulting materials, formulated as 1@AHSP and 2@AHSP, also featured (i) an exceptional antiviral activity against herpes simplex virus type 1 and human adenovirus (HAd-5) and (ii) a remarkable antibacterial activity against Gram-negative bacteria. Docking experiments, interaction with human serum albumin, mass spectrometry, and antioxidation studies provided insights into the mechanism of antimicrobial action. By reporting these new silver CPs driven by adamantoid building blocks and the derived starch-based materials, this study endows a facile approach to access biopolymers and interfaces capable of preventing and reducing the proliferation of a broad spectrum of different microorganisms, including bacteria, fungi, and viruses.

The Greater Celandine: Identification and Characterization of an Antimicrobial Peptide from Chelidonium majus.

Chelidonium majus, known as Greater Celandine, is a latex-bearing plant that has been leveraged for its anticancer and antimicrobial properties. Herein, C. majus aerial tissue is mined for the presence of antimicrobial peptides. A highly abundant cysteine-rich peptide with a length of 25 amino acids, deemed CM-AMP1, is characterized through multiple mass spectrometric approaches. Electron-activated dissociation is leveraged to differentiate between isoleucine and leucine residues and complement conventional collision-induced dissociation to gain full sequence coverage of the full-length peptide. CM-AMP1 shares little sequence similarity with any proteins in publicly available databases, highlighting the novelty of its cysteine landscape and core motif. The presence of three disulfide bonds in the native peptide confers proteolytic stability, and antimicrobial activity is greatly decreased upon the alkylation of the cysteine residues. Synthetic variants of CM-AMP1 are used to confirm the activity of the full-length sequence and the core motif. To assess the biological impact, E. coli was grown in a sublethal concentration of CM-AMP1 and quantitative proteomics was used to identify proteins produced by the bacteria under stress, ultimately suggesting a membrane lytic antimicrobial mechanism of action. This study integrates multiple analytical methods for molecular and biological characterization of a unique antimicrobial peptide identified from C. majus.

Graphene-based metal/metal oxide nanocomposites as potential antibacterial agents: a mini-review.

Antimicrobial resistance (AMR) is a rising issue worldwide, which is increasing prolonged illness and mortality rates in the population. Similarly, bacteria have generated multidrug resistance (MDR) by developing various mechanisms to cope with existing antibiotics and therefore, there is a need to develop new antibacterial and antimicrobial agents. Biocompatible nanomaterials like graphene and its derivatives, graphene oxide (GO), and reduced graphene oxide (rGO) loaded with metal/metal oxide nanoparticles have been explored as potential antibacterial agents. It is observed that nanocomposites of GO/rGO and metal/metal oxide nanoparticles can result in the synthesis of less toxic, more stable, controlled size, uniformly distributed, and cost-effective nanomaterials compared to pure metal nanoparticles. Antibacterial studies of these nanocomposites show their considerable potential as antibacterial and antimicrobial agents, however, issues like the mechanism of antimicrobial action and their cytotoxicity need to be explored in detail. This review highlights a comparative analysis of graphene-based metal and metal oxide nanoparticles as potential antibacterial agents against AMR and MDR.

Antimicrobial Activities of Stigmasterol from Piper crocatum In Vitro and In Silico

The high incidence of oral health issues and antibiotic resistance has stimulated research into discovering novel antimicrobial drugs. Prior evidence suggests that red betel leaves (Piper crocatum Ruiz and Pav) possess potential antimicrobial properties, including the presence of stigmasterol, a bioactive compound. However, the proteins precisely inhibited by stigmasterol compounds have not been identified as target proteins in the mechanism of action of stigmasterol as an oral antimicrobial agent or proteins involved in the virulence system of pathogenic oral microorganisms. The objective of this research is to identify and predict the antimicrobial mechanism of action of the stigmasterol compound isolated from red betel against specific proteins using a molecular docking approach. The methods employed for this investigation are as follows: Stigmasterol extracted from P. crocatum Ruiz and Pav was utilized as a ligand. Positive controls for each protein were antibiotics or substrates. The study findings indicate that the stigmasterol compound exhibits antibacterial and antifungal properties against pathogenic oral microorganisms in vitro as well as in silico against the crucial antibacterial enzymes MurA and PBP in addition to the pivotal antifungal enzyme exo‐β‐1,3‐glucanase and lanosterol‐14‐α‐demethylase. Therefore, it can be inferred that the stigmasterol present in Red Betel leaves could potentially function as an antimicrobial agent by impeding the spread of pathogenic oral microorganisms.

Green synthesis of Silver Nanoparticles and their antimicrobial applications

The exceptional antibacterial properties of silver nanoparticles (Ag NPs) and their prospective uses in different fields have attracted a lot of interest in contemporary times. The chemical agents used in the preparation of Ag NPs are hazardous to human health and the environment. In contrast to chemical approaches, green synthesis techniques involve the use of natural resources, which accomplish the principles of green chemistry and sustainable development goals (SDGs). In this regard, this review article delves into a comprehensive analysis of the green synthesis methods employed for the production of Ag NPs and their utilization as diverse antimicrobial agents. In addition to exploring the many antimicrobial uses of Ag NPs production, this article attempts to give a thorough examination of the processes behind the antibacterial activity of Ag NPs. This review provides in-depth mechanisms of antimicrobial action, including rupture of membranes, production of reactive oxygen species (ROS), and disruption of cellular functions. Thus, this article explores recent insights into green synthesis approaches for the preparation of Ag NPs which are effectively utilized as antimicrobial agents.

Nanoparticles and Their Antibacterial Application in Endodontics.

Root canal treatment represents a significant challenge as current cleaning and disinfection methodologies fail to remove persistent bacterial biofilms within the intricate anatomical structures. Recently, the field of nanotechnology has emerged as a promising frontier with numerous biomedical applications. Among the most notable contributions of nanotechnology are nanoparticles, which possess antimicrobial, antifungal, and antiviral properties. Nanoparticles cause the destructuring of bacterial walls, increasing the permeability of the cell membrane, stimulating the generation of reactive oxygen species, and interrupting the replication of deoxyribonucleic acid through the controlled release of ions. Thus, they could revolutionize endodontics, obtaining superior results and guaranteeing a promising short- and long-term prognosis. Therefore, chitosan, silver, graphene, poly(lactic) co-glycolic acid, bioactive glass, mesoporous calcium silicate, hydroxyapatite, zirconia, glucose oxidase magnetic, copper, and zinc oxide nanoparticles in endodontic therapy have been investigated in the present review. The diversified antimicrobial mechanisms of action, the numerous applications, and the high degree of clinical safety could encourage the scientific community to adopt nanoparticles as potential drugs for the treatment of endodontic diseases, overcoming the limitations related to antibiotic resistance and eradication of the biofilm.