Broad Antibacterial Activity Research Articles

Exploration of Phage-Agrochemical Interaction Based on a Novel Potent Phage LPRS20-Targeting Ralstonia solanacearum.

Phage therapy has the potential to alleviate plant bacterial wilt. However, the knowledge gap concerning the phage-agrochemical interaction impedes the broader application of phages in agriculture. This study characterized a phage isolate and investigated its interactions with agrochemicals. A novel species within the Ampunavirus genus was proposed, serving phage LPRS20 as a type phage with a broad lytic range and significant antibacterial activity against Ralstonia solanacearum strains infecting tobacco, chili, or tomato. Sensory evaluation of the morphology of tobacco leaves suggested that phage application resulted in negligible harm to plants. Investigations into phage-agrochemical interactions revealed synergisms when LPRS20 was delivered 4 h before thiodiazole-copper as well as LPRS20 in combination with low-concentration berberine. Overall, our findings reveal that phage LPRS20 represents a novel, effective, and eco-friendly biocontrol agent against tobacco bacterial wilt in vivo and in vitro and contributes to the potential integration of phages and agrochemicals for controlling soil-borne pathogens.

Multifunctional poloxamer-based thermo-responsive hydrogel loaded with human lactoferricin niosomes: In vitro study on anti-bacterial activity, accelerate wound healing, and anti-inflammation

Chronic wound infections are attributed to delayed tissue repair, which remains a major clinical challenge in long-term health care. Particularly, infections with antibiotic resistance have more serious effects on health, often resulting in unsuccessful treatments. Thus, antimicrobial peptide (AMP)-based therapy holds promise as a potential therapeutic approach to overcoming drug resistance. Conventional wound dressing is a passive strategy for wound care that is not capable of eradicating pathogens and promoting tissue repair. In this study, we aim to construct an advanced wound dressing; a thermo-responsive hydrogel incorporated with lactoferricin (Lfcin) niosome (Lfcin-Nio/hydrogel) for bacterial pathogen treatment. The Lfcin-loaded niosome (Lfcin-Nio) has a particle size of 396.91 ± 20.96 nm, 0.38 ± 0.01 of PdI, −10.5 ± 0.3 mV of ζ potential, and 72.30 ± 7.05 % Lfcin entrapment efficiency. Lfcin-Nio exhibited broad antibacterial activity on both drug-susceptible and drug-resistant strains, and also on bacteria residing in the biofilm matrix. The Lfcin-Nio/hydrogel was fabricated from 0.5 % w/v poloxamer 188–20 % w/v poloxamer 407, and supplemented with Lfcin-Nio and epidermal growth factor (EGF). The physical properties of Lfcin-Nio/hydrogels showed elasticity, swelling ability, and strong injectability with responsiveness to 33–37 °C temperatures. The biological properties of Lfcin-Nio/hydrogels exhibited a bactericidal effect against drug-resistant strains of S. aureus and P. aeruginosa, and showed less toxicity to the human skin fibroblast. It also promoted the healing of scratches by 55 % within 6 h, compared to the wound closure rate of 20 % in the cell control. The inflammatory response of the Lfcin-Nio/hydrogel-treated cells was reduced via suppression of IL-1β and COX-2 mRNA expressions. From this study, Lfcin-Nio/hydrogels can be suggested as a modern wound dressing that possesses multifunctional and beneficial properties for the management of chronic wound infections.

Potential Use and Chemical Analysis of Some Natural Plant Extracts for Controlling Listeria spp. Growth In Vitro and in Food.

Listeria are Gram-negative intracellular foodborne pathogens that can cause invasive infections with high mortality rates. In this work, the antibacterial activity of ten essential oils, infusion extracts, and decoction extracts of some medicinal plants was tested against Listeria monocytogenes and listeria ivanovii strains. The effects of different physical conditions including temperature, pH, sodium chloride, and some organic acids were studied. The results showed that the water extracts gave the maximum bacterial inhibition, while ethanolic extract was inactive against the tested Listeria spp. The antibiotic sensitivity of L. monocytogenes LMG10470 and L. ivanovii LMZ11352 was tested against five antibiotics including imipenem, levofloxacin, amikacin, ampicillin, and amoxicillin. Imipenem was the most effective antibiotic, resulting in inhibition zones of 40 mm and 31 mm for L. monocytogenes and L. ivanovii, respectively. When imipenem mixed with Syzygium aromaticum oil, Salvia officinalis oil, Pimpinella anisum infusion, and Mentha piperita infusion each, the water extract of Moringa oleifera leaves and seeds against LMG10470 and LMZ11352 resulted in broader antibacterial activity. The antimicrobial activity of both Pimpinella anisum and Mentha piperita plant extracts is related to a variety of bioactive compounds indicated by gas chromatography-mass spectrometry analysis of these two plant extracts. These two plant extracts seemed to contain many chemical compounds elucidated by gas chromatography-mass spectrometry (GC-MS) and infrared radiation spectra. These compounds could be classified into different chemical groups such as ethers, heterocyclic compounds, aromatic aldehydes, condensed heterocyclic compounds, ketones, alicyclic compounds, aromatics, esters, herbicides, saturated fatty acids, and unsaturated fatty acids. The use of these natural compounds seems to be a useful technological adjuvant for the control of Listeria spp. in foods.

Non-releasing poly (ionic liquid) based hydrogel accelerates diabetic wound healing

Persistent bacterial colonization, abnormal inflammatory responses, and impaired angiogenesis pose significant challenges to effective wound repair, particularly in diabetic wounds. Employing exogenous bioactive substances in wound dressings is a recognized approach to dynamically respond to the wound microenvironment and accelerate the repair process. However, this strategy can lead to the development of drug resistance and induce further tissue damage. To address these challenges, we are synthesizing a novel hydrogel for diabetic wound treatment using functional poly (ionic liquid) and modified dextran. The hydrogel is characterized by its excellent tissue adhesion, exceptional self-healing capacity, and substantial compressive deformation. It exhibits broad antibacterial activity, reduces the expression of pro-inflammatory cytokines and enhances the healing in diabetic wounds. Its efficacy is superior to that of the positive control group. This innovative non-releasing hydrogel presents as a promising alternative to conventional antibiotics, offering significant potential for the treatment and healing of diabetic chronic wounds.

Antibacterial mechanism of the methanol extract of Thamnolia subuliformis (Ehrh.) W. Culb against Staphylococcus aureus.

Thamnolia subuliformis (Ehrh.) W. Culb is a species of lichen with edible and medicinal applications in China. Our previous studies demonstrated that the methanol extract of Thamnolia subuliformis (METS) exhibits broad antibacterial activity and stability against foodborne pathogens. This study aimed to investigate the antibacterial mechanism of METS against Staphylococcus aureus using nontargeted metabolomics, focusing on cell wall and membrane damage. The results revealed that the minimum inhibitory concentration (MIC) was 0.625mg ml-1 and that METS had good biosafety at this concentration. METS caused significant damage to the cell wall and membrane integrity, based on both morphological observation by electron microscopy and the leakage of alkaline phosphatase, protein, and nucleic acid in the cell cultures. Treatment with METS at the MIC disrupted the lipid metabolism of S. aureus, causing a decrease in the metabolism of various phospholipids and sphingolipids in the cell membrane and an increase in the ratio of saturated fatty acids to unsaturated fatty acids. Moreover, it influenced intracellular amino acid and energy metabolism. These results shed light on the antibacterial mechanism of METS against S. aureus while also serving as a reference for the further development of natural antibacterial compounds derived from Thamnolia subuliformis.

Antibacterial Hydrogel Adhesives Based on Bifunctional Telechelic Dendritic-Linear-Dendritic Block Copolymers.

Antibiotic-resistant pathogens have been declared by the WHO as one of the major public health threats facing humanity. For that reason, there is an urgent need for materials with inherent antibacterial activity able to replace the use of antibiotics, and in this context, hydrogels have emerged as a promising strategy. Herein, we introduce the next generation of cationic hydrogels with antibacterial activity and high versatility that can be cured on demand in less than 20 s using thiol-ene click chemistry (TEC) in aqueous conditions. The approach capitalizes on a two-component system: (i) telechelic polyester-based dendritic-linear-dendritic (DLDs) block copolymers of different generations heterofunctionalized with allyl and ammonium groups, as well as (ii) polyethylene glycol (PEG) cross-linkers functionalized with thiol groups. These hydrogels resulted in highly tunable materials where the antibacterial performance can be adjusted by modifying the cross-linking density. Off-stoichiometric hydrogels showed narrow antibacterial activity directed toward Gram-negative bacteria. The presence of pending allyls opens up many possibilities for functionalization with biologically interesting molecules. As a proof-of-concept, hydrophilic cysteamine hydrochloride as well as N-hexyl-4-mercaptobutanamide, as an example of a thiol with a hydrophobic alkyl chain, generated three-component networks. In the case of cysteamine derivatives, a broader antibacterial activity was noted than the two-component networks, inhibiting the growth of Gram-positive bacteria. Additionally, these systems presented high versatility, with storage modulus values ranging from 270 to 7024 Pa and different stability profiles ranging from 1 to 56 days in swelling experiments. Good biocompatibility toward skin cells as well as strong adhesion to multiple surfaces place these hydrogels as interesting alternatives to conventional antibiotics.

A comprehensive study on Geranium robertianum L. antibacterial potential.

The research aimed to optimize the ultrasound-assisted extraction of secondary metabolites and the antibacterial activity of the plant species Geranium robertianum. The phytochemical profiles of the optimized extracts, as well as their antibacterial and synergistic activity with an antibiotic and their potential mechanisms of action and cytotoxicity, were examined. Response Surface Methodology was used to optimize extraction conditions. Optimized ethanol and acetone extracts were tested via microdilution, checkerboard, time-kill kinetics, and cell membrane permeability methods. The extracts displayed broad antibacterial activity with minimum inhibitory concentrations ranging from 1.25 to 20mg ml-1. In addition, the extract synergistically reacted with gentamicin against gentamicin-resistant strains of Escherichia coli and Staphylococcus aureus, enhancing the efficacy of the antibiotic up to 32-fold. The extracts demonstrated strain-dependent bactericidal activity in a 24-h time interval. They increase the permeability of the cell membrane, thus disrupting its normal functioning. The cytotoxic concentration (CC50) on human keratinocytes was 1771.24±5.78µg ml-1 for ethanol extract, and 958.01±6.14µg ml-1 for acetone extract. Kaempferol, ellagic acid, quercetin, and rutin were recognized as the main components in both extracts. The findings of this study indicate that the extracts of G. robertianum can be considered as potential natural antibacterial agents in the control of microorganisms.

Amoxicillin-Clavulanate Breakpoints Against Enterobacterales: Rationale for Revision by the Clinical and Laboratory Standards Institute.

Amoxicillin-clavulanate (AMC) is among the most frequently prescribed antibiotics globally. It has broad antibacterial activity against gram-positive, gram-negative, and anaerobic bacteria and has been used to treat infections caused by a broad range of pathogens. AMC breakpoints against Enterobacterales were initially set in the 1980s. However, since that time, increases in antibiotic resistance, advances in pharmacokinetic/pharmacodynamic analyses, and publication of additional clinical data prompted a reassessment by the Clinical and Laboratory Standards Institute (CLSI) Subcommittee on Antimicrobial Susceptibility Testing. Based on this contemporary reappraisal, the CLSI retained the Enterobacterales breakpoints but revised comments regarding dosing associated with use of the AMC breakpoints in the 2022 supplement of M100. This viewpoint provides insight into the CLSI breakpoint reevaluation process and summarizes the data and rationale used to support these revisions to the AMC Enterobacterales breakpoint.

UiO-66/AgNPs Coating for Dental Implants in Preventing Bacterial Infections

Titanium (Ti)–based biomaterials lack inherent antimicrobial activities, and the dental plaque formed on the implant surface is one of the main risk factors for implant infections. Construction of an antibacterial surface can effectively prevent implant infections and enhance implant success. Silver nanoparticles (AgNPs) exhibit broad antibacterial activity and a low tendency to induce drug resistance, but AgNPs easily self-aggregate in the aqueous environment, which significantly impairs their antibacterial activity. In this study, UiO-66/AgNP (U/A) nanocomposite was prepared, where zirconium metal–organic frameworks (UiO-66) were employed as the confinement matrix to control the particle size and prevent aggregation of AgNPs. The bactericidal activity of U/A against methicillin-resistant Staphylococcus aureus and Escherichia coli increased nearly 75.51 and 484.50 times compared with individually synthesized Ag. The antibacterial mechanism can be attributed to the enhanced membrane rupture caused by the ultrafine AgNPs on UiO-66, leading to protein leakage and generation of intracellular reactive oxygen species. Then, U/A was loaded onto Ti substrates (Ti-U/A) by using self-assembly deposition methods to construct an antibacterial surface coating. Ti-U/A exhibited excellent antibacterial activities and desired biocompatibility both in vitro and in vivo. The U/A nanocomposite coating technique is thus expected to be used as a promising surface modification strategy for Ti-based dental implants for preventing dental implant infections.

Isolation and Identification of Effective Probiotics on Drug-Resistant Acinetobacter baumannii Strains and Their Biofilms.

This study aimed to identify, assess, and isolate strong lactobacilli demonstrating broad antibacterial and anti-biofilm activity against drug-resistant strains of Acinetobacter baumannii. Additionally, the mechanism of inhibition of these organisms was to be determined. Over a 6-month period (from December 2021 to June 2022), 53 clinical A. baumannii strains were collected from clinical samples. Twenty probiotic strains were isolated from local dairy products. Antibacterial activity of Lactobacillus strains' cell-free supernatant (CFS) was identified using the agar well diffusion method and the microbroth dilution test. Anti-biofilm effect was performed by the microtiter plate assay. The MTT assay was also used to look into the probiotics' cytotoxic effects on the L929 fibroblast cell line. During the 6-month period, 53 clinical A. baumannii strains were obtained and identified. Out of 20 lactobacillus strains, the CFS of a lactobacillus strain (named L9) showed an inhibitory effect against all A. baumannii strains. Using the broth microdilution method, it was shown that the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of CFS extracts of L9 strains against A. baumannii strains were both ¼ mg/mL. The result of the anti-biofilm showed that the selected probiotic could inhibit biofilm formation. The most common organic acid produced by all Lactobacillus strains, according to the HPLC method, was lactic acid, which was followed by acetic acid. The L929 fibroblast cell line was used in the cytotoxicity assay, which revealed that 100% of the cells in the L929 fibroblast cell line survived treatment with successive doses of CFSs for a full day. The probiotic strain isolated from local yogurt in this study showed potential anti-biofilm and antimicrobial properties against all drug-resistant Acinetobacter isolates. Given the increasing interest in probiotic microorganisms based on their high health benefits, further studies are recommended on the mechanisms of action between probiotics and A. baumannii strains to find new solutions for biological control and treatment of these infections without the use of antibiotics.

Efficacy and safety of lascufloxacin for nursing- and healthcare-associated pneumonia: A single-arm, open-label clinical trial

BackgroundNursing- and healthcare-associated pneumonia (NHCAP) constitutes most of the pneumonia in elderly patients including aspiration pneumonia in Japan. Lascufloxacin (LSFX) possesses broad antibacterial activity against respiratory pathogens, such as Streptococcus spp. And anaerobes inside the oral cavity. However, the efficacy and safety of LSFX in NHCAP treatment remains unknown. We aimed to evaluate the efficacy and safety of LSFX tablets in the treatment of patients with NHCAP. MethodsIn this single-arm, open-label, uncontrolled study, LSFX was administered to patients with NHCAP at 24 facilities. The study participants were orally administered 75 mg LSFX once daily for 7 days. The primary endpoint was the clinical efficacy at the time of test of cure (TOC). The secondary endpoints included clinical efficacy at the time of end of treatment (EOT), early clinical efficacy, microbiological efficacy, and safety analysis. ResultDuring the study period, 75 patients provided written informed consent to participate and were included. Finally, 56 and 71 patients were eligible for clinical efficacy and safety analyses, respectively. The median age of the patients was significantly high at 86 years. All patients were classified as having moderate disease severity using the A-DROP scoring system. LSFX tablets demonstrated high efficacy rates of 78.6 % at TOC and 89.3 % at EOT. The risk factors for resistant bacteria or aspiration pneumonia did not affect clinical efficacy. No severe adverse events associated with the study drugs were observed. ConclusionOral LSFX is an acceptable treatment option for moderate NHCAP in elderly patients who can take oral medications.

What do we know about Macrolides Immunomodulatory Therapeutic Potential in Respiratory Disease in 2023

The broad antibacterial activities of macrolides have led to their widespread use on infections, particularly for respiratory infections. Many of the macrolide-susceptible microorganisms are respiratory pathogens known to be associated with exacerbations of asthma, chronic obstructive pulmonary disease (COPD), bronchiectasis (BE) and cystic fibrosis (CF). Macrolides have been widely used to treat respiratory diseases, often beyond its acute antimicrobial use (Table 1), and they have long been accepted to show effects on inflammatory and immune cells, mucus secretion, and epithelial cell differentiation. Anti-inflammatory and immuno-modulatory actions, independent of their actions on bacteria, add to their therapeutic benefit in infectious and chronic inflammatory disorders, recognition that dates to the 1960s.

Broad photodynamic antibacterial activity of a functionalized, highly fluorinated sensitizer

Acquired resistance allows bacteria to survive antibiotics, a major health problem. Antibacterial photodynamic inactivation (PDI) relies on photoproduction by a photosensitizer of difficult-to-counteract reactive oxygen species (ROS). We report that a -COOH- functionalized fluoroalkyl-rich fluoro zinc phthalocyanine containing 48 F atoms, is soluble and stable in 99:1% H2O:DMF, and produces 1O2 in quantum yields exceeding 0.30. The photosensitizer induces 93.70–97.28% inhibition of Gram-negative E. coli and P. aeruginosa, and Gram-positive B. subtilis and S. aureus. Such durable, functionalized photosensitizers, exhibiting both inert C-F bonds and reactive-COOH groups, unlike perfluorinated phthalocyanines might be advantageous for constructing covalently bonded new materials with long-term bacterial inactivation activity, useful in a variety of operating environments.

Simple Purification and Antimicrobial Properties of Bacteriocin-like Inhibitory Substance from Bacillus Species for the Biopreservation of Cheese.

Bacteriocins may be used as natural preservatives and antibiotic substitutes in various foods. However, the multistep purification process of bacteriocins results in high production costs, which is an obstacle to their commercial use and consumer accessibility. In this study, a bacteriocin-like inhibitory substance (BLIS) from Bacillus spp. isolated from Korean fermented foods was partially purified using the aqueous two-phase system (ATPS). The maximum activity of the BLIS was achieved for ATPS composed of PEG 1000 (15% [w/w])/ammonium sulfate (20% [w/w])/sodium chloride (2% [w/w]), which caused BLIS activity to increase by 3 times with a 99% recovery rate. In particular, B. amyloliquefaciens Y138-6 BLIS exhibited broad antibacterial activity, high resistance to acid-base stress, and excellent thermal stability. This antibacterial substance inhibited the growth of aerobic bacteria and fungi on the walls of cheese and ripening rooms. These antibacterial properties have been shown to increase food safety and have the potential for use as biopreservatives. Moreover, considering that the execution of the ATPS requires only salts and PEG, it is a simple, environmentally friendly, and cost-effective process and may have industrial applications in the recovery of BLIS from fermentation broth.

Unraveling the genome of Bacillus velezensis MEP218, a strain producing fengycin homologs with broad antibacterial activity: comprehensive comparative genome analysis

Bacillus sp. MEP218, a soil bacterium with high potential as a source of bioactive molecules, produces mostly C16–C17 fengycin and other cyclic lipopeptides (CLP) when growing under previously optimized culture conditions. This work addressed the elucidation of the genome sequence of MEP218 and its taxonomic classification. The genome comprises 3,944,892 bp, with a total of 3474 coding sequences and a G + C content of 46.59%. Our phylogenetic analysis to determine the taxonomic position demonstrated that the assignment of the MEP218 strain to Bacillus velezensis species provides insights into its evolutionary context and potential functional attributes. The in silico genome analysis revealed eleven gene clusters involved in the synthesis of secondary metabolites, including non-ribosomal CLP (fengycins and surfactin), polyketides, terpenes, and bacteriocins. Furthermore, genes encoding phytase, involved in the release of phytic phosphate for plant and animal nutrition, or other enzymes such as cellulase, xylanase, and alpha 1–4 glucanase were detected. In vitro antagonistic assays against Salmonella typhimurium, Acinetobacter baumanii, Escherichia coli, among others, demonstrated a broad spectrum of C16–C17 fengycin produced by MEP218. MEP218 genome sequence analysis expanded our understanding of the diversity and genetic relationships within the Bacillus genus and updated the Bacillus databases with its unique trait to produce antibacterial fengycins and its potential as a resource of biotechnologically useful enzymes.

Antimicrobial effects and metabolomics analysis of cell-free supernatant produced by Pediococcus acidilactici LWX 401 isolated from Yunnan traditional pickles

Foodborne pathogens pose a significant risk to human health via the food chain. Here, we evaluated the antibacterial effects of cell-free supernatant (CFS) of Pediococcus acidilactici (P. acidilactici) LWX 401 isolated from food-grade Chinese traditional pickles and found that it exhibited broad antibacterial activity against multidrug-resistant gram-negative Escherichia coli (E. coli) O157:H7 and yogurt-derived gram-positive Staphylococcus aureus (S. aureus), with inhibition zone sizes of 23.10 ± 0.80 and 20.53 ± 0.07 mm, respectively (all P < 0.001 compared with the controls). Moreover, the CFS exhibited strong thermostability and pH tolerance and was capable of inhibiting the formation of biofilms of these foodborne pathogens. Notably, the LWX 401 CFS inhibited both E. coli O157:H7 and S. aureus contamination in milk samples under different storage temperatures (4 °C, 25 °C, and 35 °C), with considerable bacterial reduction by 1–7 log CFU/mL compared with untreated controls. Additionally, the potential antibacterial metabolites (VIP >1, adjusted P < 0.05, and fold-change >2; n = 56) were identified in the LWX 401 CFS by UHPLC-QE-MS metabolomic analysis, and these metabolites were mostly lipids (25.73%) and organic acids (23.30%). Our results provide insights for the development of bio-preservatives against foodborne pathogens in the milk industry.

Design, synthesis, and antimicrobial evaluation of new antipyrine derivatives bearing thiazolopyridazine and pyrazolothiazole scaffolds

In the current research, a new set of antipyrine–thiazole hybrids were designed and synthesized and screened for their antimicrobial activities against Gram-positive and Gram-negative bacteria and fungal strains using ciprofloxacin and nystatin as reference drugs. The antipyrine derivatives 3a, 5a, 7c, and 11a revealed promising and broad antibacterial activity especially against S. aureus, followed by in vitro enzyme inhibitory assay against S. aureus DNA gyrase to predict the mechanism of action. The thiazole 3a and pyrazolo[4,3-d]thiazole 7c afforded superior inhibitory activity against S. aureus DNA gyrase (IC50 = 0.292 ± 0.15 and 0.255 ± 0.10 µM, respectively) in comparison with ciprofloxacin (IC50 = 0.331 ± 0.20 µM). Finally, the in silico molecular docking and ADME studies were established to give better rationalization and optimization of efficient new antimicrobial leads.

Determination Of Total Flavonoid Content Of Yellow Wood (Arcangelisia Flava (L.) Merr) Extract And Antibacterial Activity Against Staphylococcus aureus

Yellow wood (Arcangelisia flava) is a medicinal plant that has received little attention. Merr and (L.). Yellow wood has antibacterial, antioxidant, anti-hyperlipidemic, and anti-cancer properties. Furthermore, yellow wood is known to contain a range of flavonoid compounds, such as hydroxylarcangelicin, which has broad antibacterial activity. The purpose of this research is to investigate the total flavonoid content of yellowwood extract as well as its antibacterial activity against Staphylococcus aureus bacteria. The manufacturing of methanol extract, characterization of simplisia, phytochemical screening, and determination of the total flavonoid levels of the yellow wood methanol extract by a visible spectroscopic approach were all part of this stage of research. Next, use chloramphenicol as a positive control and dimethyl sulfoxide (DMSO) as a negative control to test antibacterial activity against Staphylococcus aureus. The results of this study can be concluded to show that the total flavonoid levels in the methanol extract of yellow wood at a metanol concentration of 80% were 228,314 ± 5,4171 mg QE/g. At a 90% concentration of 245.993 ± 6.7626 mg QE/g and a 100% concentration of 265.953 3.0853 mg QE/g.&#x0D; Keywords: Yellow wood; Flavonoids; Spektrofotometri Visible; Stphylococcus aureus;

Modification and development of optical, thermal, dielectric properties and antibacterial activity of PVA/SA blend by Ag/Se nanofillers: Nanocomposites for energy storage devices and food packaging applications

Silver nanoparticles (Ag NPs) were synthesized using Capsicum annuum extract, which is a cost-effective and green technique. At the same time, selenium nanoparticles (Se NPs) were prepared by sol-gel technique. Then, a series of PVA/SA blend samples filled with different contents of Ag–Se nanoparticles were prepared via the solution casting way. The nanocomposite films were investigated using different measurements. XRD scans of the nanocomposites displayed a decrease in the crystallinity of the PVA/SA blend with increasing the content of Ag–Se NPs as nanofillers in the PVA/SA matrix. FT-IR spectra indicated the complexation and positive interactions between the PVA/SA blend and Ag–Se NPs. The thermal stability of the polymeric samples was improved after the addition of the nanofiller (Ag–Se NPs), as shown by TGA scans. Moreover, the indirect/direct optical energy gap decreased from 3.96/5.28 to 2.73/3.59 eV with increasing concentrations of Ag–Se NPs, confirming the improvement in the optical properties of the filled polymeric samples, as indicated by UV/visible spectra. Dielectric studies revealed that the filling of Ag–Se NPs increases the defects and leads to a greater number of dipoles within the blend and, thus, an increase in the dielectric constant and dielectric loss of the nanocomposite samples. The antibacterial test showed that all filled samples had broad antibacterial activity against Gram-positive and Gram-negative bacteria compared to pure PVA/SA blend and that it was linearly related to the nanofillers concentrations in the polymeric matrix. Improvements in thermal, optical, and electrical properties make the present nanocomposite samples suitable for multiple functions in many applications, such as high-density energy storage and flexible electronic devices. In contrast, the enhancement in the antibacterial activity could indicate that these nanocomposites can also be used for antibacterial packaging and biomedical purposes.

Evaluation of Antibacterial and Antiviral Compounds from Commiphora myrrha (T.Nees) Engl. Resin and Their Promising Application with Biochar

Commiphora myrrha (T.Nees) Engl. resin extracts were prepared via immersion in extraction solvents (hot water, DMSO, hexane, ethanol, and methanol) which have various physical properties, such as different polarity and dielectric constant values. Methanolic C. myrrha (T.Nees) Engl. resin extracts showed broad antibacterial activity against isolated airborne bacteria. All methanolic C. myrrha (T.Nees) Engl. resin extracts were analyzed using GC-MS and Furanoeudesma-1,3-diene and curzerene were found as the main terpenoids. In addition, the methanolic C. myrrha (T.Nees) Engl. resin extracts were found to have antiviral activity (81.2% viral RNA inhibition) against the H1N1 influenza virus. Biochars (wood powder- and rice husk-derived) coated with C. myrrha (T.Nees) Engl. resin extracts also showed antiviral activity (22.6% and 24.3% viral RNA inhibition) due to the adsorption of terpenoids onto biochar. C. myrrha (T.Nees) Engl. resin extract using methanol as the extraction solvent is a promising agent with antibacterial and antiviral efficacy that can be utilized as a novel material via adsorption onto biochar for air filtration processes, cosmetics, fertilizers, drug delivery, and corrosion inhibition.