Strong Antimicrobial Activity Research Articles

Sustainable Finished Leather Preservation

Part 1 of the current paper described the green synthesis of myrobalan capped copper nanoparticles for the preservation of the finished leather. In Part II of the current study, Copper Nanoparticles (CuNPs) were synthesized using green synthesis with wattle (tannin) extract as a reducing agent. Green synthesis is the preferred approach for the synthesis of metal nanoparticles due to its eco-friendly and cost-effectiveness for the preservation of finished leather. To improve the antibacterial qualities of leather with different types of finishes, the resin finished leather was coated with synthesized wattle copper nanoparticles (W-CuNPs). The chemical constituents of wattle induce the reduction of Cu2+ ions to CuNPs with the capping process and also remain as a stabilizing agent for the capping process. The formation of W-CuNPs was confirmed by UV-Spectroscopy at an absorbance of 467 nm. The identified functional groups such as -OH, C=C, and C-N were analyzed by Fourier transform infrared spectrum (FT-IR) which are responsible for the reduction and stabilization of copper nanoparticles. The spherical shape of the nanoparticles was ascertained by Scanning Electron Microscope (SEM), whereas Energy dispersive X-ray (EDX) studies confirmed the presence of copper with 65%. The average particle size of W-CuNPs was found to be 96 nm. The zeta potential value of -24 mv affirmed the stability of the W-CuNPs. The maximum zone of inhibition was 12 mm against Gram-positive (Bacillus subtilis) and 11 mm against Gram-negative (Serratia marcescens) bacteria on W-CuNPs coated finished leather, which exhibits strong antimicrobial activity. Hence, CuNPs synthesized by wattle extract have the potential to preserve the finished leather and its products as an antibacterial agent.

Silver nanoparticles biogenically synthesised using Maclurodendron porteri extract and their bioactivities

Silver nanoparticle is widely used in various field including medical, cosmetic, food and industrial purposes due to their unique properties in electrical conductivity, thermal, and biological activities. In the medical field, silver nanoparticles (AgNPs) have been reported to have strong antimicrobial and cytotoxic activities. This study aimed to synthesize and characterize silver nanoparticles (AgNPs) using Maclurodendron porteri (MP) extract and to evaluate the antimicrobial and cytotoxic activities of the synthesised MP-AgNPs. Green method of Ultrasound Assisted Extraction (UAE) was used to extract the leaves of M. porter. Liquid Chromatography -Mass Spectrometry/Quadrupole time-of-flight (LC-MS/QTOF) was used to identify the compounds in the leaf extract of M. porteri. Characterisation of the synthesised nanoparticles involved ultraviolet–visible (UV–Vis), Fourier Transform Infrared (FTIR), scanning electromagnetic microscopy (SEM), Zeta potential Analyzer and Particle Size Analyzer. The cytotoxic assay was conducted on MCF-7 and Caco-2 cell lines by MTT assay. Antimicrobial activity was tested on Gram-negative and Gram-positive bacteria using the disc diffusion method. Based on LC-MS/QTOF analysis, 430 compounds were found. The identified major compounds consist of amino acids, polyphenols, steroids, terpenoids and heterocyclic compounds which possibly act as reducing agents. 1 mM, 5 mM and 10 mM of silver nitrate solution were mixed with the leaf extract to form silver nanoparticles. 1.2 mg/ml of MP-AgNPs were found to have antibacterial activity against B. subtilis, S. aureus, E. coli, and P. aeruginosa with inhibitory zones of 8.0 ± 0.36 mm, 8.5 ± 0.45 mm, 7.5 ± 0.36 mm, and 9.0 ± 0.40 mm respectively. MP-AgNPs showed no cytotoxic activity against Caco-2 and MCF-7 cells. In conclusion, the presence of major amine compounds such as 10,11-dihydro-10,11-dihydroxyprotriptyline and harderoporphyrin in the extract facilitated the synthesis of AgNPs and the nanoparticle showed weak bioactivities in the assay conducted.

Effect of fermentation conditions on antioxidative, antimicrobial and techno-functional properties of Camellia sinensis leaves

Introduction and Aim: Fermented food is an excellent source of nutrition as it contains promising bioactive compounds. Black tea is a fermented product and the most commonly used beverage. In the present study, the effects of various fermentation conditions and drying techniques on the proximate nutritional analysis, phytochemicals, tannin, antioxidative, and antimicrobial activity of Camellia sinensis leaves were examined. Materials and Methods: The FTIR analysis was performed to detect the presence of different functional groups. Using standard methods, total phenol, flavonoid, and tannin content were determined. The antioxidant activity was determined by using DPPH, ABTS, and FRAPS assays. Results: The results showed a decrease in protein content and an increase in ash, moisture, and crude fiber content, indicating that the samples’ nutritional profiles were improved after fermentation processing. The FTIR results showed the presence of hydroxy, carboxyl, amine, alkane, alkene, and alkyne bonding. The antioxidant activity of fermented samples was more than that of unfermented ones. Fermented samples had strong antimicrobial activity against Escherichia coli. An increase in TPC and TFC contributed to the rise in the antioxidant activity of the fermented sample. An increase in TSS suggested improvement in flavour and sweetness. Antimicrobial activity against Escherichia coli, demonstrated their potential as a natural antimicrobial agent. Conclusion: The enhanced antimicrobial activity of fermented tea leaves highlights the importance of the fermentation process in producing tea with improved microbial control and possible health benefits.

Antimicrobial activity of lipids extracted from Hermetia illucens reared on different substrates

As the problem of antimicrobial resistance is constantly increasing, there is a renewed interest in antimicrobial products derived from natural sources, particularly obtained from innovative and eco-friendly materials. Insect lipids, due to their fatty acid composition, can be classified as natural antimicrobial compounds. In order to assess the antibacterial efficacy of Hermetia illucens lipids, we extracted this component from the larval stage, fed on different substrates and we characterized it. Moreover, we analyzed the fatty acid composition of the feeding substrate, to determine if and how it could affect the antimicrobial activity of the lipid component. The antimicrobial activity was evaluated against Gram-positive Micrococcus flavus and Gram-negative bacteria Escherichia coli. Analyzing the fatty acid profiles of larval lipids that showed activity against the two bacterial strains, we detected significant differences for C4:0, C10:0, C16:1, C18:3 n3 (ALA), and C20:1. The strongest antimicrobial activity was verified against Micrococcus flavus by lipids extracted from larvae reared on strawberry, tangerine, and fresh manure substrates, with growth inhibition zones ranged from 1.38 to 1.51 mm, while only the rearing on manure showed the effect against Escherichia coli. Notably, the fatty acid profile of H. illucens seems to not be really influenced by the substrate fatty acid profile, except for C18:0 and C18:2 CIS n6 (LA). This implies that other factors, such as the rearing conditions, larval development stages, and other nutrients such as carbohydrates, affect the amount of fatty acids in insects.Key points• Feeding substrates influence larval lipids and fatty acids (FA)• Generally, there is no direct correlation between substrate FAs and the same larvae FAs• Specific FAs influence more the antimicrobial effect of BSF lipidsGraphical abstract

Metagenomic analysis of hot spring soil for mining a novel thermostable enzybiotic.

The misuse and overuse of antibiotics have contributed to a rapid emergence of antibiotic-resistant bacterial pathogens. This global health threat underlines the urgent need for innovative and novel antimicrobials. Endolysins derived from bacteriophages or prophages constitute promising new antimicrobials (so-called enzybiotics), exhibiting the ability to break down bacterial peptidoglycan (PG). In the present work, metagenomic analysis of soil samples, collected from thermal springs, allowed the identification of a prophage-derived endolysin that belongs to the N-acetylmuramoyl-L-alanine amidase type 2 (NALAA-2) family and possesses a LysM (lysin motif) region as a cell wallbinding domain (CWBD). The enzyme (Ami1) was cloned and expressed in Escherichia coli, and its bactericidal and lytic activity was characterized. The results indicate that Ami1 exhibits strong bactericidal and antimicrobial activity against a broad range of bacterial pathogens, as well as against isolated peptidoglycan (PG). Among the examined bacterial pathogens, Ami1 showed highest bactericidal activity against Staphylococcus aureus sand Staphylococcus epidermidis cells. Thermostability analysis revealed a melting temperature of 64.2 ± 0.6°C. Overall, these findings support the potential that Ami1, as a broad spectrum antimicrobial agent, could be further assessed as enzybiotic for the effective treatment of bacterial infections. KEY POINTS: • Metagenomic analysis allowed the identification of a novel prophage endolysin • The endolysin belongs to type 2 amidase family with lysin motif region • The endolysin displays high thermostability and broad bactericidal spectrum.

Biogenic synthesis of silver, gold, and palladium nanoparticles using moringa oleifera seeds: exploring photocatalytic, catalytic, and antimicrobial activities

In this study, we explored the green synthesis of metal nanoparticles (Ag-NPs, Au-NPs, and Pd-NPs) using Moringa oleifera seed (MOS) extract, which is known for its nutrient density, antioxidant properties, anti-inflammatory effects, and potential benefits in managing cholesterol, blood sugar levels, as well as promoting digestion, skin, and hair health. The nanoparticles’ size was controlled by varying the concentration of MOS extract. The successful formation of Au-NPs and Ag-NPs was confirmed through surface plasmon resonance (SPR), while the absence of absorption at 420 nm indicated the reduction of Pd2+ ions to Pd0, affirming the synthesis of Pd-NPs. The nanoparticles exhibited mono-dispersed, spherical shapes with confirmed crystallinity. Sizes were determined as 28 nm for Pd-NPs, 5 nm for Au-NPs, and 19 nm for Ag-NPs. The MOS extract’s phenols and proteins played a crucial role in reducing and stabilising Ag-NPs, Au-NPs, and Pd-NPs. Notably, the synthesised nanoparticles demonstrated strong antimicrobial activity, particularly against Salmonella typhi, making them potential antibacterial agents. The catalytic efficiency of Au-NPs, Ag-NPs and Pd-NPs was studied using the reduction of 4-Nitrophenol (4-NP) by NaBH4 to 4-Aminophenol. Additionally, Au-NPs showed enhanced photocatalytic degradation rate constant and catalytic reaction rate constant of 0.0038/min and 0.261/min respectively, due to their small size and increased surface area. By combining a green synthesis approach with an in-depth analysis of properties and diverse applications, this study provides valuable insights into the immense potential of MOS-assisted metal nanoparticles for various technological and environmental advancements.

<em>In-vitro </em>antibacterial activity of <em>Boerhavia diffusa</em> leaf extract against <em>Staphylococcus aureus </em>and<em> Escherichia coli</em>

Plants are playing a significant role in maintaining human health and improving the wealth of human life and are a better alternative to synthetic drugs that display negative side effects, such as sensitization reactions, and disruption of the metabolic processes in the body via interaction with the body system. The main objective of this study was to evaluate the in-vitro antibacterial activity of Green Leafy Vegetable (GLVs), namely Boerhavia diffusa. Fully matured fresh leaf samples were collected from different localities in the Western Province, Sri Lanka. The acetone, ethanol and aqueous extracts of leaf samples were tested for antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), by using agar well diffusion method at the test concentrations of 0.25, 0.50 and 0.75 mg/μL. The maximum inhibitory effect was observed in the ethanol extracts of leaf samples against both bacterial strains at 0.75 mg/μL concentration. Ethanol extract of B. diffusa showed the maximum inhibition effect (17.8±0.3 mm) against S. aureus and it was the most susceptible bacteria than E. coli in plant extracts of all three solvents. All three extracts of B. diffusa showed most effective antibacterial activity against both bacterial strains, tested. The MIC values obtained from plants exhibited antibacterial activity ranged between 0.0625 and 0.25 mg/μL. The lowest MIC values were given by the ethanol extracts. Thus, the ethanol extract of this plant leaf sample was the most effective extract, which exhibited strong antimicrobial activity on both bacterial strains. Presence of bioactive compounds in these plant extracts could be the reason to indicate high antibacterial activity.

Eugenol improves salt tolerance via enhancing antioxidant capacity and regulating ionic balance in tobacco seedlings.

Salt stress inhibits plant growth by disturbing plant intrinsic physiology. The application of exogenous plant growth regulators to improve the plant tolerance against salt stress has become one of the promising approaches to promote plant growth in saline environment. Eugenol (4-allyl-2- methoxyphenol) is the main ingredient in clove oil and it is known for its strong antioxidant and anti-microbial activities. Eugenol also has the ability of inhibiting several plant pathogens, implying the potential use of eugenol as an environmental friendly agrichemical. However, little is known about the possible role of eugenol in the regulation of plant tolerance against abiotic stress. Therefore, here we investigated the effectiveness of phytochemical eugenol in promoting salt tolerance in tobacco seedlings through physiological, histochemical, and biochemical method. The seedling roots were exposed to NaCl solution in the presence or absence of eugenol. Salt stress inhibited seedling growth, but eugenol supplementation effectively attenuated its effects in a dose-dependent manner, with an optimal effect at 20 µM. ROS (reactive oxygen species) accumulation was found in seedlings upon salt stress which was further resulted in the amelioration of lipid peroxidation, loss of membrane integrity, and cell death in salt-treated seedlings. Addition of eugenol highly suppressed ROS accumulation and reduced lipid peroxidation generation. Both enzymatic and non-enzymatic antioxidative systems were activated by eugenol treatment. AsA/DHA and GSH/GSSG were also enhanced upon eugenol treatment, which helped maintain redox homeostasis upon salinity. Eugenol treatment resulted in an increase in the content of osmoprotectants (e.g. proline, soluble sugar and starch) in salt-treated seedlings. Na+ levels decreased significantly in seedlings upon eugenol exposure. This may result from the upregulation of the expression of two ionic transporter genes, SOS1 (salt-hypersensitive 1) and NHX1 (Na+/H+ anti-transporter 1). Hierarchical cluster combined correlation analysis uncovered that eugenol induced salt tolerance was mediated by redox homeostasis and maintaining ionic balance in tobacco seedlings. This work reveals that eugenol plays a crucial role in regulating plant resistant physiology. This may extend its biological function as a novel biostimulant and opens up new possibilities for improving crop productivity in the saline agricultural environment.

A Comprehensive Study on Lathyrus tuberosus L.: Insights into Phytochemical Composition, Antimicrobial Activity, Antioxidant Capacity, Cytotoxic, and Cell Migration Effects.

In this study, in vitro antioxidant, antimicrobial, cytotoxic, and cell migration effects of phenolic compounds of Lathyrus tuberosus leaves, known in the Transylvanian ethnomedicine, were investigated. Ultra-high-performance liquid chromatography-tandem mass spectrometry was employed for the analysis of the ethanolic and aqueous extracts. The antimicrobial properties were determined using a conventional microdilution technique. Total antioxidant capacity techniques were used using cell-free methods and cell-based investigations. Cytotoxic effects were conducted on 3T3 mouse fibroblasts and HaCaT human keratinocytes using a multiparametric method, assessing intracellular ATP, total nucleic acid, and protein levels. Cell migration was visualized by phase-contrast microscopy, employing conventional culture inserts to make cell-free areas. Together, 93 polyphenolic and monoterpenoid compounds were characterized, including flavonoid glycosides, lignans, hydroxycinnamic acid, and hydroxybenzoic acid derivatives, as well as iridoids and secoiridoids. The ethanolic extract showed high antioxidant capacity and strong antimicrobial activity against Bacillus subtilis (MIC80 value: 354.37 ± 4.58 µg/mL) and Streptococcus pyogenes (MIC80 value: 488.89 ± 4.75 µg/mL). The abundance of phenolic compounds and the results of biological tests indicate the potential for L. tuberosus to serve as reservoirs of bioactive compounds and to be used in the development of novel nutraceuticals.

Antimicrobial Evaluation of Anthraquinones and Preanthraquinone from the Root Extract of Aloe kefaensis

The aim of this study was to isolate antimicrobial compounds from the roots of Aloe kefaensis, a plant endemic to Ethiopia and used to treat various microbial infections by traditional healers. The air-dried and powdered plant material was sequentially extracted with petroleum ether, dichloromethane, acetone, and methanol. Then, each solvent extract was evaluated for its in vitro antimicrobial activity against four bacterial (Escherichia coli, Bacillus cereus, Salmonella typhimurium, and Staphylococcus aureus) and one fungal (Candida albicans) strains using the agar disk diffusion method. Superior antimicrobial activity was exhibited against all the strains by dichloromethane extract, with the highest activity observed against S. typhi (inhibition zone diameter of 23.0 mm at 200 mg/mL). Due to similarity in their TLC profile, the acetone and dichloromethane extracts were combined and subjected to silica gel column chromatography for fractionation and isolation of the compounds. Separation of these extracts using silica gel column chromatography resulted in four anthraquinones: deoxyerythrolaccin (1), chrysophanol (2), laccaic acid D-methyl ester (3), and 3, 8-dihydroxy-1-methylanthraquinone-2-carboxylic acid (4) and one preanthraquinone, aloesaponol II (5). The structure of these compounds was established using NMR (1D and 2D) spectroscopic analysis and comparison with reported literature data. The isolated compounds were evaluated for antimicrobial activity and showed varying degrees of potency. Compounds 2 and 4 showed the highest activity against Salmonella typhimurium at 10 mg/mL, with a zone of inhibition of 28.5 and 25.0 mm, respectively, in comparison to gentamicin (26.0 mm inhibition zone diameter at 10 mg/mL). Therefore, this strong antimicrobial activity of the extracts and isolates supports the traditional usage of Aloe kefaensis to treat microbial diseases.

Antifungal potential and chemical composition of Tagetes lunulata Ort. essential oil for the control of Trichophyton rubrum Malmsten

The essential oils of aromatic and medicinal plants are an important resource used to control several health conditions; however, information about their composition and antimicrobial activity is scarce. This study used a gas chromatography-mass spectrometry (GC-MS) to analyze the composition of the essential oil (EO) of Tagetes lunulata Ort., a Mexican endemic plant, known as wild cempaxúchitl. The major components of the EO include: verbenone (47.17%), α-pinene (10.93%), 1,1,1-Trifluoro-2-hexanone (9.63%), β-caryophyllene (6.10%), germacrene-D (4.99%), L-verbenone (4.89%), and E-tagetone (4.44%). The disk agar diffusion method was used to evaluate the antimicrobial activity of T. lunulata against Trichophyton rubrum (athlete's foot). A significant antimicrobial activity was observed with a ≥60% EO concentration. The dilution method was used to determine the minimum inhibitory concentration (MIC): 200 μg ml-1. The T. lunulata EO recorded a strong antimicrobial activity against T. rubrum; therefore, it is a natural alternative for the control of natural antifungals.

Polymeric coating doped with nanomaterials for functional impact on different substrates

Microorganism contamination on substrate surfaces is arousing increasingly concern as a serious health issue. In this research work, antimicrobial water-based acrylic paint containing silver nanoparticles (Ag NPs) was prepared using the facile Ag+ in situ reduction process, in which AgNO3 and reducing agent sodium acrylate were refluxed with acrylic polymeric solution to obtain an antimicrobial and antifungal polymeric material for substrate coating. The Synthesized antimicrobial and antifungal water-based acrylic paint were characterized by different spectroscopic techniques. The FTIR and UV–Visible spectroscopic analyses were investigated to study the water-based acrylic paint structure as well as the significant impact of Ag NPs on the paint matrix. The UV–Visible and FTIR Spectra peak shows successful integration of Ag NPs within the polymer matrix without altering the core functional groups of the paint. The water based acrylic paint exhibited a strong antimicrobial activity, revealed substantial inhibition zones against all four strains of Gram negative represented by Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae and Gram-positive represented by Bacillus cereus. The coated film on substrate also shows great inhibition zone which exhibit a strong antimicrobial activity. Moreover, water based acrylic paint also exhibited a great antifungal activity, revealed substantial zone of inhibition against the Aspergillus niger, Aspergillus terreus and Rhizopus arrhizus fungal strains. Also, the coated film showed the best adhesion at 50% and 80% solution of polymeric coating sample as compared to pure or very dilute sample coating. This innovative approach has the potential to revolutionize varies industries from healthcare to construction.

Total synthesis of [β-HIle]2-nodupetide: effect of ester to amide substitution on its antimicrobial activity.

The increasing prevalence of deaths due to multidrug-resistant bacteria (MDRB) in infectious disease therapy has become a global health concern. This led to the development of new antimicrobial therapeutic agents that can combat resistance to pathogenic bacteria. The utilization of natural peptide compounds as potential antimicrobial agents is very promising. Nodupetide, a cyclodepsipeptide with very strong antimicrobial activity against Pseudomonas aeruginosa was isolated from the fermentation of Nodulisporium sp. Unfortunately, one of its residues (3S,4S)-3-hydroxy-4-methylhexanoic acid (HMHA) is not commercially available and the synthesis strategies applied have not been successful. Hence, we synthesized its cyclopeptide analogue [β-HIle]2-nodupetide by replacing HMHA with isoleucine homologue. A combination of solid- and solution-phase peptide synthesis was successfully carried out to synthesize [β-HIle]2-nodupetide with an overall yield of 10.4%. The substitution of HMHA with β-homoisoleucine (β-HIle) changed the ester bond into an amide bond in nodupetide's backbone. The analogue was considerably inactive against Pseudomonas aeruginosa. It can be concluded that the ester bond is crucial for the antimicrobial activity of nodupetide.

Recent developments in the bio-mediated synthesis of CoFe2O4 nanoparticles using plant extracts for environmental and biomedical applications.

Conventional methods for the synthesis of nanoparticles often involve toxic chemicals, exacerbating environmental issues in the context of climate change and water scarcity. Green synthesis using plant extracts offers a sustainable and viable alternative for CoFe2O4 nanoparticle production, but understanding the mechanisms and applications of this method is challenging. Here, we review the synthesis and applications of CoFe2O4 nanoparticles using plant extracts with emphasis on biomedical activity and water treatment. Plant extract-mediated CoFe2O4 nanoparticles exhibit high surface area, small particle size, unique morphology, sufficient band gap energy, and high saturation magnetization. These nanoparticles demonstrate strong antimicrobial and anticancer activities, highlighting their potential in biomedical treatments. Green CoFe2O4 are effective in removing organic dyes, heavy metals, and pharmaceuticals from water, promoting cleaner water resources. Challenges such as scalability and reproducibility still remain, but ongoing research aims to optimize synthesis protocols and explore new applications. This work underscores the importance of sustainable nanotechnology in addressing environmental challenges.

Influence of pomelo pericarp essential oil on the structural characteristics of gelatin-arrowroot tuber flour-based edible films.

The present study examined the comprehensive effects of incorporating pomelo pericarp essential oil (PEO) at varying concentrations (0.5, 1.0, 1.5, and 2.0%) into gelatin-arrowroot tuber flour (GEL-ATF) based edible films and evaluated the influence on various structural properties. ATF was prepared from Maranta arundinacea L. tubers using a carefully controlled method to ensure its quality and suitability as a polysaccharide base in film formulations. The results indicated that adding PEO to the GEL-ATF films decreased L, a, and b color values and increased opacity values, especially at higher PEO concentrations. Furthermore, the appearance of both GEL-ATF and GEL-ATF-PEO films exhibited similar characteristics. Incorporating PEO significantly reduced moisture content and water vapor permeability (WVP), indicating enhanced barrier properties against moisture. Additionally, an increase in PEO concentration resulted in decreased film solubility. A decrease in tensile strength (TS) but an increase in elongation at break (EAB) was observed in the GEL-ATF films with higher PEO concentrations (>1% PEO). Slight variations in thermal degradation patterns with increased PEO addition in GEL-ATF were noticed, while X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FTIR) results of the tested films provided insights into structural and chemical modifications, indicating changes in crystallinity and molecular interactions upon increased PEO concentration in the film compositions. The microstructural observations confirmed that PEO incorporation led to smoother film surfaces, suggesting a more uniform matrix, which could enhance the film's barrier and mechanical properties. Furthermore, applying PEO into GLE-ATF films exhibited strong antimicrobial activity against Bacillus cereus ATCC 11778. Overall, the present study found that the higher PEO (>1%) concentrations significantly influenced the physical and mechanical properties of GEL-ATF-based edible films. This newly developed edible film could be an effective alternative to inedible polymers for sustainable food packaging solutions.

Myrtenol's Effectiveness against Hospital-Acquired Methicillin-Resistant Staphylococcus aureus: Targeting Antibiofilm and Antivirulence Properties.

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) several years ago highlighted the challenge of multidrug-resistant infections, emphasizing the critical need for innovative treatment approaches. Myrtenol, known for its antibacterial and antibiofilm properties, holds promise as a potential treatment option. This study aimed to evaluate the effectiveness of myrtenol against MRSA. The collected MRSA isolates were assessed for antimicrobial susceptibility following the Clinical and Laboratory Standards Institute (CLSI) guidelines 2023. Biofilm formation by MRSA was evaluated using the tissue culture plate (TCP) technique. The minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), and minimal biofilm inhibitory concentration (MBIC) of myrtenol against MRSA were determined both individually and in combination with antibiotics. Real-time PCR was employed to investigate the impact of myrtenol on the expression of virulence genes (sarA, agrA, and icaD) across the isolates. In this study, MRSA was identified in 90 out of 400 cases (22.5%) of hospital-acquired pathogens. Among the collected MRSA isolates, 53 out of 90 (59%) were found to produce biofilms. The MIC of myrtenol was comparable to the MBC across all tested isolates, they were almost the same. Combinations of myrtenol with most tested antibiotics exhibited synergistic effects exceeding 60%. Among the 53 biofilm-producing isolates, 45 isolates (85%) expressed the sarA gene, 49% expressed the agrA gene, and all biofilm-producing MRSA isolates (100%) expressed the icaD gene. A notable reduction in the relative quantity (RQ) values of virulence gene expression was observed after treatment with the MBIC of myrtenol across all tested isolates. Myrtenol demonstrated strong antimicrobial activity against MRSA, notably reducing the expression of key virulence genes linked to biofilm formation. This suggests its potential as a therapeutic agent for treating biofilm-associated MRSA infections.

Antimicrobial activity of some fungal isolates from Red Sea in Egypt

The study investigates the antimicrobial efficiency of fungi from the Red Sea in El-Quseir and Sharm El-Sheikh districts. The fungi’s active metabolites were tested for their antibacterial activity against pathogenic germs. The fungi were grown on nutritional agar media and malt extract agar medium. The extracts of marine fungi were also investigated for their cell death potential, using lung carcinoma cells as a cell line. The results of our study demonstrated the strong antimicrobial activity of marine fungi towards both Gramme positive and Gramme negative microorganisms, particularly against Serratia marcenscens and Salmonella. The ethyl acetate extract from El-Quseir (a sand source) and Sharm El-Sheikh (a water source) demonstrated the highest inhibition zones, measuring 37 mm and 35 mm, respectively. The normal cell line (MRC-5) was subjected to cytotoxic effects that demonstrated antibacterial and anticancer properties, while also exerting non-significant toxicity on active concentrations. Comparing petroleum ether, chloroformic, and methanolic extracts to ethyl acetate extract, and our results showed that the latter had the lowest antibacterial activity. Against medically used lung cancer cell lines, marine fungi shown antitumor activity.

Mentha pulegium ekstraktı güçlü in vitro antimikrobiyal ve sitotoksik etki göstermiştir

Mentha pulegium is a medicinally important and well-known plant and used for various purposes such as medicinal, nutritional and spice. We are analyzed to observe the antimicrobial, antioxidant and cytotoxic properties of M. pulegium extracts in this study. The antimicrobial activity of M. pulegium was tested using the agar well method. MIC, MBC and antimicrobial activity were tested on Staphylococcus aureus (ATCC 25923), Klebsiella pneumoniae (ATCC 700603), Escherichia coli (ATCC 25322), Bacillus megaterium (DSM32) and Candida albicans (FMC17) microorganisms. Clindamycin (2 µg) and Amoxicillin (30 µg) were used as positive control and Dimethylsulfoxide (DMSO) as negative control. Cytotoxic activity of extracts at different concentrations obtained from solvents such as acetone, chloroform and methanol using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test method; µg/ml cytotoxic activity and cell death patterns after exposure to different concentrations of the extracts on human breast cancer (MDA-MB-231), human pancreatic cancer (PANC1), human ovarian cancer (OVCAR3) and human lung cancer (A549) cell lines determined accordingly. As a result, it was determined that M. pulegium extract has a strong antimicrobial activity spectrum and cytotoxic effect.

Effect of Phycoerythrin on Antimicrobial Activity and Shelf-life Extension of the Nile Tilapia (Oreochromis niloticus) at Refrigerator Temperature.

The present study was performed to evaluate the effect of phycoerythrin (PE) treatment extracted from Nostoc sp. on the shelf-life extension of the Nile Tilapia (Oreochromis niloticus) fillet at 4°C and 8°C. After extraction and purification of pigment in BG-110 medium, the pigment PE was extracted and purified with 56% ammonium sulfate followed by dialysis. After that, the effect of pigment on Escherichia coli and Staphylococcus aureus were investigated. The fillet samples were immersed in pigment solution, and their physicochemical, microbiological and sensory properties were examined. The results showed that the concentration and purity of the pigments increased after the dialysis. The results from performed chemical tests and total number of living mesophilic bacteria, psychrotrophic bacteria, Staphylococcus aureus coagulase positive, and coliform bacteria of the samples compared to the blank sample showed that sample treated with algae extracts were able to control the increase in these parameters. In these tests, the highest levels belonged to Nile Tilapia fillet sample Nile Tilapia fillet coated with PE solution at a temperature 8°C and the lowest amount was observed with fillet coated with PE solution at a temperature of 4˚C (P≤0.05). The results of sensory evaluation showed that the highest score of taste, texture, color, and total acceptance were observed for Nile Tilapia fillet coated with PE solution at temperature 8°C. In conclusion, the extract pigments from Nostoc sp. has strong antimicrobial activity and can maintain the quality parameters for controlling of spoilage bacteria and extend the shelf-life of Oreochromis niloticus.

Gum Arabic edible coating embedded aqueous plant extracts: Interactive effects of partaking components and its effectiveness on cold storage of fresh-cut capsicum

This study investigated the interactive effects of components in gum Arabic-based coating enriched with aqueous extracts of Syzygium aqueum, Diploglottis bracteata, and Tasmannia lanceolata on properties of edible coating/film. Response surface methodology was employed to optimize the films based on their physical and permeability properties. It was shown that the concentration of the components significantly influenced these characteristics. The coating demonstrated strong antimicrobial activity against Pseudomonas viridiflava, a main cause of soft rot in vegetables, when using 5.00% S. aqueum, 5.00% D. bracteata, and 9.35% T. lanceolata with lower concentrations of gum Arabic and MCT oil. The optimized coating was applied to fresh-cut red capsicum, and its effects were evaluated. The coating effectively inhibited microbial growth, maintaining low bacterial load (ca. 3 log CFU. g−1) until day 10 of storage. Sensory evaluations also showed positive liking scores for appearance, aroma, and flavor, indicating that the coating enhanced the overall sensory experience of the capsicum. Despite these positive outcomes, challenges regarding moisture retention and firmness preservation during storage were identified. The coating did not adequately preserve these qualities, highlighting the need for further research to optimize the formulation for commercial applications. Nonetheless, incorporating plant extracts in the gum Arabic-based coating holds promise for extending the shelf life of fresh-cut capsicum while improving its sensory attributes.