Agar Disc Diffusion Method Research Articles

Effect of Silver Complex on Graphene Oxide Alginate (GOAlgAg) for Antibacterial Studies

The effect of the silver complex on graphene oxide and its antibacterial studies was reported in this work. Graphene oxide (GO) has a high specific surface area and is well-known for being an ideal substrate material for growing silver nanoparticles. The simplified Hummer's method was chosen to prepare GO and Silver nanoparticles (AgNPs), which have been decorated on the surface of GO during the reduction of silver complex solution [Ag(NH3)2OH] in GO aqueous solution. The obtained nanocomposite was analyzed by using Ultraviolet-visible spectrophotometry (UV-Vis) and X-ray diffraction (XRD). The antibacterial performance against Gram-negative bacteria (Escherichia coli) and Gram-positive bacteria (B. subtilis) was investigated using the disk agar diffusion method. The diameter of the inhibition zone indicates the effectiveness of GOAlgAg in preventing these bacteria from growing while displaying the nanocomposite as a promising material for antibacterial-related applications. The best antibacterial properties were found in a sample of 5.0:2.5ml GOAlgAg, which shows the highest inhibition zone, 0.85cm toward Escherichia coli and 1.03cm toward B. subtilis.

Nasal Carriage of Antimicrobial-Resistant Staphylococci by Fallow Deer (Dama dama) Taken in a Natural Park of Tuscany, Central Italy.

Wild animals are recognized as significant reservoirs for various zoonotic pathogens, including antibiotic-resistant bacteria. This study aimed to investigate the presence of Staphylococcus spp. strains in fallow deer (Dama dama) inhabiting a natural preserve in Central Italy and to examine the phenotypic and genotypic antimicrobial resistance and the presence of some virulence genes among the isolates. During July and December 2022, nasal swabs were collected from 175 fallow deer, which were then analyzed through bacteriological cultures. In total, 176 Staphylococcus spp. strains were isolated and subsequently identified using MALDI-TOF mass spectrometry. S. aureus was the most abundant species with 66 (37.5%) strains, followed by S. hyicus, 34 (19.31%) strains, S. sciuri, 32 (18.18%) strains, S. chromogenes, 27 (15.34%) strains, S. xylosus, 11 (6.25%) strains, S. warneri, 5 (2.84%) strains, and S. devriesei, 1 (0.56%) strain. Antimicrobial susceptibility was assessed for each isolate via the agar disk diffusion method, testing a panel of 13 molecules belonging to 9 antimicrobial classes. The highest resistance rates were detected for penicillin (29.55%), rifampicin (22.73%), and amikacin (20.45%). Notably, intermediate susceptibility was observed for erythromycin (61.93%), enrofloxacin (28.41%), and ceftiofur (21.02%). Conversely, the strains exhibited particularly high susceptibility to amoxicillin/clavulanic acid (99.43%), cefoxitin (97.73%), and vancomycin (96.02%). Based on the results, 32 (18.18%) isolates were classified as multidrug-resistant (MDR). Two strains of S. chromogenes and one strain of S. xylosus, both resistant to penicillin, tested positive for the blaZ gene. No methicillin-resistant strains were found, and none of the isolates harbored genes associated with enterotoxin and toxic shock syndrome toxin production. This study highlights the potential role of wildlife, particularly fallow deer, as reservoirs of antibiotic-resistant Staphylococcus spp. strains. Such findings underscore the importance of monitoring wildlife for antimicrobial resistance, which could have implications for public health and veterinary medicine.

Biological Activity of Essential Oil from Two Aromatic Species on the in vitro Control of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc.

Objective: Essential oils (EO) from aromatic and medicinal plants (AMP) are considered a viable alternative for controlling phytopathogenic fungi of agronomic importance. This study evaluated the antifungal activity of thyme (Thymus vulgaris L.) and rue (Ruta graveolens L.) essential oils against Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. Design/Methodology/Approach: The antifungal activity was assessed using the agar disk diffusion method, with concentrations ranging from 10% to 100% of each EO. The phytochemical composition was analyzed using GC-MS. Morphological observations were conducted with a scanning electron microscope (SEM). Results: Significant antifungal activity was observed at concentrations of 50-100% of thyme EO. Rue EO exhibited a fungistatic effect for up to six days. Phytochemical analysis identified carvacrol (35.95%) and p-cymene (41.18%) as the major components in thyme EO, and 2-nonanone (24.24%) and 2-undecanone (68.69%) in rue EO. Findings/conclusions: The evaluated EOs significantly impacted fungal morphology at 60% concentration. The strong antifungal activity of thyme EO against C. gloeosporioides suggests its potential as an eco-friendly control alternative.

Antimicrobial effects of eugenol-based micro- vs. nano-emulsions: Evaluation of shelf-life enhancement in Sikhye

This study investigated the antibacterial properties of micro-emulsions (MEs) and nano-emulsions (NEs) containing eugenol and rice bran oil to enhance the shelf life of Sikhye, a traditional Korean rice beverage. The emulsions were evaluated using the agar disk diffusion method and minimum inhibitory concentration (MIC) tests against Escherichia coli, Bacillus cereus, and Staphylococcus aureus. The results demonstrated that MEs exhibited larger inhibition zones and lower MIC values than NEs, indicating superior antibacterial activity. The application of these emulsions in Sikhye revealed that a higher eugenol content and larger droplet size effectively inhibited bacterial growth. The study also found that, while rice bran oil contributed to physical stability, it did not enhance the antimicrobial effect and, in some cases, promoted bacterial growth. Overall, these findings suggest that eugenol-rich MEs could serve as effective natural preservatives, improving the safety and shelf life of Sikhye and potentially other food products.

Synthesis and application of WO3/PVA nano composite for antibacterial and thermal insulation

Abstract Insulation of glass material is very important for sustainable environment in this real world without compromising its primary function. The aim of this research is to provide robust solution by synthesis the Nano Tungsten trioxide particles via the chemical precipitation method. Developed WO3 NPs Characterized by using x-ray diffraction for; crystal structure, compound composition, and average crystalline size. Scanning Electron Microscopy (SEM) employed to analyze the shape and dimensions of the WO3 NPs. Explored the potential thermal insulation and antibacterial attributes by coating 1%, 3%, 5% and 7% concentration of synthesized WO3 NPs in polyvinyl alcohol onto a sodium silicate glass substrate (4 × 4 inches; 2 mm thickness) by using 50 μm doctor blade. WO3/PVA solution showed the antibacterial properties measure by agar disc diffusion method on gram positive and negative bacterial culture S. coli and E. bacterial culture and the obtained results after incubation were showing very minor zone of incubation as compare to previous studies. Thermal insulation of coated glass samples were increased with % of WO3 NPs concentration in PVA and validate by significant coefficient of determination (R2 = 0.985).

Relationship between the strength of biofilm production and the presence of pvl and mecA genes in Staphylococcus aureus isolated from skin and soft tissue infections

This research sought to investigate the association between the occurrence of the pvl and mecA genes and the strength of biofilm formation, as well as to assess the efficacy of vancomycin and ceftaroline against Staphylococcus aureus strains obtained from skin and soft tissue infections (SSTIs). A total of 134 S. aureus isolates were collected from SSTI patients and identified through standard microbiological techniques. Vancomycin and ceftaroline susceptibility testing were performed using the agar dilution and disc diffusion methods, respectively. PCR analysis was conducted to identify the nuc, mecA, and pvl genes. Biofilm production was measured using the tissue culture plate method. Methicillin-resistant S. aureus (MRSA) represented 58.2 % of the isolates. All isolates displayed biofilm-forming capability, with 10.4 % classified as high-grade biofilm producers, 85.7 % of which were positive for the mecA gene (P = 0.02). 16.4 % of the isolates had pvl gene and 59 % of PVL-positive strains identified as MRSA. Most of the low-grade biofilm producers had the pvl gene (P = 0.03). Vancomycin susceptibility was observed in 98.5 % of isolates, with an MIC₅₀ of 1 μg/mL in 51.4 % of cases. Among MRSA strains, 1.4 % exhibited intermediate resistance to vancomycin, with MICs between 4 and 8 μg/mL. No resistance to ceftaroline was found. The results demonstrate a significant association between biofilm production strength and the occurrence of the mecA and pvl genes; mecA correlated with increased biofilm production, while pvl was associated with lower biofilm levels. These findings offer valuable insights for future studies, suggesting that ceftaroline could be an effective alternative to vancomycin for treating MRSA-related SSTIs, particularly given the increasing resistance to vancomycin.

Evaluation of Antimicrobial Activity of Methanol Extract of Abrus precatorius Leaf Against Selected Clinical Isolates (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albican)

Abrus precatorius is one of the herbal plants that have been reported to have medicinal properties. The leaves is widely used for the treatment of cough, cancer and swollen tonsils. Abrus precatorius is also known for its abundant chemical constituents that could be very important antibacterial agent. This study evaluated the antimicrobial activity of Abrus precatorius leaf extracts against isolated clinical bacteria and fungi. The study employed agar disc diffusion method of antimicrobial sensitivity testing (50 µg/mL, 100 µg/mL, 200 µg/mL and 400 µg/mL), and Minimum Inhibitory Concentration (MIC) model. The results showed a dose dependent antimicrobial potential of Abrus precatorius leaf extract against the test organisms with zone of inhibition ranging from 4 – 18mm against Escherichia coli, 6 – 19mm against Pseudomonas aeruginosa, 4 -22mm against Staphylococcus aureus and 2 – 15mm against Candida albican. The extract also showed an MIC of 25mg/ml for Staphylococcus aureus, 50mg/ml for Escherichia coli and Pseudomonas aeruginosa and the least MIC of 100mg/ml for Candida albican. The outcome of the study suggest that Abrus precatorius leaf extract exert broad spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria. These findings validate the use of the plants for the treatment of infections, and indicate the potential roles of the plants in drug development programs of the pharmaceutical industry.

Synthesis, Antimicrobial and Antioxidant Activity with in silico ADMET Prediction, Molecular Docking and Dynamics Studies of Carbazole Ring Containing Thiazole Schiff Bases

AbstractTwelve thiazole hybrids (2 a–2 l) were synthesized in this study incorporating with Schiff base and carbazole scaffolds and characterized by spectral analyses. Antimicrobial activity and antioxidant potency were investigated by agar disc diffusion method and DPPH free radical scavenging assays where trimethyldihydrothiazole 2 c had revealed its higher efficacy in both biological studies. It had displayed IC50 of 25.55±0.40 μg/mL which is higher than the standard ascorbic acid (IC50=41.31±1.83 μg/mL) as well as dihydrothiazoylchromenone 2 e showed promising antioxidant activity with IC50 value of 40.82±0.54. The compound 2 c satisfied all the ADME properties and toxicological parameters with maximum drug score value (0.39) among all derivatives. Molecular docking was undertaken for higher bioactive compounds where 2 c revealed its wide range of interactions with different amino acid residues which was also endorsed with the output of molecular dynamics simulation.

Enhancing the antioxidant, antimicrobial resistance, and anticancer potency of plant-mediated SnO2 and Se doped P-SnO2 NPs by Justicia adhatoda: An in vitro approach

In this work, plant-mediated SnO2 NPs were green synthesized using Justicia adhatoda plant leaf extract, and the synthesized SnO2 powder was doped with Se nanorods at various concentrations (10 %, 20 %, and 30 %). The synthesized sample was characterized using XRD, HRSEM, SEM-EDAX, SEM-EDS, TEM, UV–Vis, and FTIR spectra. Furthermore, we investigated the antibacterial activity of P-SnO2 NPs and Se-doped P-SnO2 NPs at various concentrations of selenium (10 %, 20 %, and 30 %) against three gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumonia) and one gram-positive bacteria (Staphylococcus aureus) using the agar disc diffusion method. Furthermore, an antioxidant activity (DPHH) and cytotoxicity study (HepG2) were performed. Morphological analysis was used to identify the P-SnO2 nanoparticle shape as spherical in shape and the Se nanoparticle shape as a nanorod. The TEM image reveals that 30 % of the Se-doped P-SnO2 NPs exhibit an inner core structure. The TEM image used to identify the size of P-SnO2 NPs is 64 nm, and the Se nanorod is 4.06 nm. The 30 % Se-doped P-SnO2 NPs demonstrate good bacterial activity compared to P-SnO2, and 10 % and 20 % Se-doped P-SnO2 nanoparticles. Antioxidant activity: 30 % Se-doped P-SnO2 NPs show an excellent IC50 value compared to others; the IC50 values of 30 % Se-doped P-SnO2 NPs are 33.71 µg/ml. The cytotoxicity of 30 % Se-doped P-SnO2 NPs exhibits an IC50 value of 121 µg/ml against the HepG2 cell line. So, it is very useful for medicinal applications.

Imidazolium, pyridinium and pyrazinium based ionic liquids with octyl side chains as potential antibacterial agents against multidrug resistant uropathogenic E. coli

Urinary tract infections (UTIs) are the second most prevalent infectious disease with E. coli being the most common etiological agent behind these infections, affecting more than 150 million people globally each year. In recent decades, the emergence of multi-drug resistant (MDR) pathogens has rapidly escalated. To combat antimicrobial resistance (AMR), it is important to synthesize new biologically effective alternatives like ionic liquids (ILs) to control the bacterial infection and their spread. Ionic liquids are poorly coordinated organic salts characterized by melting points typically below 100 °C. The ability of ILs to form anionic and cationic interactions contributes to their versatile chemical, physical and biological attributes. In the present study, a total of 9 previously chemically synthesized and characterized ILs were used. For exploration of their antibacterial potential against the urinary tract infections (UTIs) caused by MDR Uropathogenic E. coli (UPEC) strains, in vitro and in vivo evaluation of ILs were performed. ILs showed pronounced zone of inhibition (ZOI), minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 29.5 mm, 3.81 μM and 5.08 μM by agar disk diffusion and broth micro-dilution methods, respectively. Scanning electron microscopy results depicted substantial morphological changes in UPEC biofilm formation ascertaining antibiofilm potential of tested ILs. Moreover, ILs showed exceptional antioxidant potential depicted by DPPH assay along with low cytotoxic effect toward mammalian cell lines (NB4), red blood cells and whole blood. Furthermore, the gene expression analysis results justified the antibacterial potential of ILs showing down-regulation of fimH, uvrY and up-regulation of csrA gene in UPEC after ILs treatment. In vivo dermal sensitivity assessment also established their non-cytotoxic behavior. In silico analysis validated these results, with the majority of the compounds exhibiting moderate to good absorption.Due to remarkable antibacterial and antioxidant potential and negligible cytoxicity, it could be inferred that ILs could serve as novel antimicrobial alternative agents in the treatment of UTIs.

Comprehensive analysis of antioxidant and antibacterial activities of water and methanol extracts of Hibiscus flower

This study provides a comprehensive investigation into the antioxidant and antibacterial properties of Hibiscus flower extracts, highlighting their potential for future applications in functional foods. The research addressed key challenges by employing a multi-faceted approach, including four distinct methods for evaluating antioxidant potential: DPPH and FRAP assays, reducing power, and chelating ability of Fe ions. Total phenolic content was quantified using the Folin–Ciocalteu method, while tannins and flavonoids were assessed via vanillin–HCl and aluminum chloride assays. Additional analyses included spectrophotometric measurement of total flavonols and anthocyanins. Antibacterial activity was determined using a modified agar disk diffusion method, with results indicating significant inhibition of Salmonella typhimurium and Staphylococcus aureus by both aqueous and methanolic extracts. Colorimetric analysis revealed a reduction in chroma and hue angles, while FTIR spectroscopy identified key functional groups, such as suberin, lipids, and polysaccharides. Notably, the antioxidant efficacy varied depending on the solvent used, with aqueous extracts showing higher total phenolic content (4325.12 mg GAE/100 g) compared to methanolic extracts (3487.05 mg GAE/100 g). The study concludes that Hibiscus flower extracts, rich in antioxidants like tannins and anthocyanins, possess significant potential for use as natural preservatives and colorants in food products, supporting their role in developing novel functional foods.

Increased incidence of methicillin resistant Staphylococcus aureus and methicillin resistant Staphylococcus epidermidis in the skin and nasal carriage among healthcare workers and inanimate hospital surfaces after the COVID-19 pandemic.

Healthcare workers in hospitals are exposed to infectious diseases that occur in the hospital making them a source of infection for the patients. It is interfaced as cross-contamination agents for MRSA and MR-CoNS, and preventive measures need to be adapted accordingly. The study aimed to assess Methicillin-Resistant Staphylococcus (MRS) on the skin and nasal cavities of healthcare workers (HCWs) and identifying isolates to the species level. Swab samples were cultured on mannitol salt agar (MSA) to obtain MRS and determine their ability to produce coagulase. Their susceptibility to antibiotics were determined by agar screening and disk diffusion methods and further identification was done at the species level. The highest percentage of methicillin resistant coagulase positive Staphylococci (MRCoPS) was reported among skins of male HCWs, (71.4%) were identified as MRSA. The highest levels of methicillin resistant coagulase negative Staphylococci (MRCoNS) were mainly detected in both nasal cavities, (75%) were identified as MRSE. MRSA was reported from doctors (p-value 0.033), whereas the highest incidence of MRSE was obtained from the nurses (p-value 0.048). This study highlighted that incidence of MRSA was mainly detected in doctors and MRCoNS in both nasal cavities. The highest percentage of MRCoNS was recovered from the patients' room followed by the reception table. Moreover, vancomycin is suggested to be highly effective in managing and controlling S. aureus, MRSA- and MRSE related infections.

Ten-year comparison of the efficiency of legal regulations of foodborne pathogens in broilers in Türkiye

Broiler meats are the primary source of foodborne pathogens, such as Campylobacter jejuni and Salmonella spp., and E. coli O157. The illegal use of antibiotics for preventive purposes or the habit of using broad-spectrum antibiotics in farms causes antibiotic resistance in these pathogens. This study compared C. jejuni, Salmonella spp. and E. coli O157 and their antibiotic resistance patterns in broiler meats in 2011-2012 and 2021-2022. The research we conducted in 2011-2012 to observe the effectiveness of the legal regulations enacted in Türkiye in 2014 and 2018 for controlling pathogens and monitoring the use of antibiotics was also repeated with a similar sample set in 2021-2022. The results showed the prevalence of C. jejuni, Salmonella spp., and E. coli O157 in 2011-2012 and 2021-2022 with 68.0%, 30.4%, 0.8% and 10.08%, 7.77%, 0.21%, respectively. The antimicrobial susceptibility tests against gentamicin, streptomycin, erythromycin, ciprofloxacin, enrofloxacin, tetracycline and oxytetracycline were performed by agar disk diffusion method. According to results in 2011-2012, all C. jejuni and Salmonella spp. were resistant to at least one tested antibiotic, with 31.57% Salmonella spp. and 16.47% C. jejuni being multidrug-resistant. In addition, one of the E. coli O157 strains was resistant to one antibiotic, and the other was resistant to two antibiotics. In 2021-2022, 81.3% C. jejuni, 46% Salmonella spp., and only one E. coli O157 were resistant to at least one tested antibiotic. Isolated strains of 8.33% C. jejuni and 21.62% Salmonella spp. were multidrug-resistant. In the past, antibiotics were used for preventative purposes, as indicated by the survey results. Today, it is evident that these rates have decreased to low levels as a result of legal regulations and monitoring.

A comprehensive review on in-vitro methods for anti- microbial activity

Microbes, also referred to as microscopic creatures because of their minuscule size and invisibility to human sight, are single-celled microorganisms. The first microorganism was discovered between 1665 and 1683 by Robert Hooke and Antoni van Leuwenhoek. There are two categories of techniques for examining microbial activity. methods used in vitro and in vivo. Experiments and tests carried out in a laboratory setting, typically without the presence of a living organism, are referred to as in vitro methods. By creating microbial cultures, cell lines, cell cultures, etc., we may do in vitro experiments. Scientists can study biological processes, assess the effects of medications, and understand systems without having to deal with the complexities of a whole organism by employing in vitro techniques. Growing cells outside of the body in a controlled setting for a range of studies is known as cell culture. Tissues are grown and kept in a lab setting for tissue culture. It is essential to research creating anti-infection therapies. To evaluate a substance's antibacterial activity, in vitro methods such as the brothdilution method and discdiffusion method are commonly used. There are different methods available for the testing of antimicrobial activity and the methods are the agar disk diffusion method, Agar well diffusion method, cross streak method, Bioautography, dilution method, Time kill test, ATP bioluminescence etc. Techniques for determining novel antimicrobial agents and testing for antibiotic susceptibility have been employed. Compared to in-vivo procedures, in vitro methods are less costly. To guarantee an accurate experimental approach, these techniques may be the answer.

Comparison of the antibacterial activity of six medicinal plants, sodium hypochlorite, and chlorhexidine against enterococcus faecalis (In vitro study)

Enterococcus faecalis is a gram-positive, facultative anaerobic bacterium recognized for its resistance to various antimicrobial agents. This organism is associated with the failure of endodontic treatments, even when potent antimicrobial irrigants are employed. Numerous medicinal plants have demonstrated antimicrobial properties that could be potentially effective against this bacterium.To evaluate the antibacterial properties of six medicinal plants in comparison to sodium hypochlorite and chlorhexidine against E. faecalis.Antibacterial susceptibility tests against E. faecalis (ATCC 29212) were performed for 200 mg/ml ethanolic extracts of Acacia Senegal, Capparis decidua, Capparis micracantha, Acacia nilotica/ Adansonia, Dobera glabra, and Moringa oleifera by Agar Disc Diffusion method. Chlorhexidine 0.2% and Sodium hypochlorite 1% were used as positive controls, and ethanol 20% as a negative control. The diameters of the inhibition zones were measured. Acacia nilotica/adansonii leaves showed the largest inhibition zone diameter against E. faecalis. It displayed a significantly greater inhibitory effect against E. faecalis than Acacia Senegal (p-value =0.005), Capparis decidua (p-value =0.02), Capparis micracantha branches (p-value =0.000), Dobera glabra leaves (p-value =0.008), and Moringa olifera leaves (p-value =0.000).Acacia nilotica leaves displayed a similar inhibition zone diameter against E. faecalis as chlorhexidine gluconate 0.2%, but it showed no statistical significance. Acacia nilotica leaves (L) and pods (P), as well as Dobera glabra branches (B), displayed a larger inhibition zone diameter against E. faecalis than Sodium hypochlorite 1%, but with no statistical significance. The leaves of Acacia nilotica exhibit the most potent antibacterial properties against E. faecalis when compared to other plants parts. They outperform the antibacterial effectiveness of 1% sodium hypochlorite and demonstrate a similar antibacterial impact to that of 0.2% chlorhexidine. Therefore, Acacia nilotica leaves could serve as an ideal irrigant potentially substituting the chemical options.

Extraction, Characterization, and Encapsulation of Cinnamon Hydrosol Obtained via Microwave-Assisted Hydrodistillation: Analysis of Antioxidant and Antimicrobial Activities

Microwave-assisted hydrodistillation (MAHD) method was employed to extract cinnamon oil and hydrosol (a byproduct). The total polyphenol content (TPC) of the cinnamon hydrosol (CH) was determined using the Folin-Ciocalteu method, and its antioxidant power was assessed through the DPPH radical reduction method. Gas chromatography was utilized to quantify the main bioactive compound (cinnamaldehyde). The disc agar diffusion method was applied to evaluate the inhibition of pathogenic microorganisms. To protect the bioactive compound, an encapsulation method involving cross-linking with calcium alginate was utilized. The capsules were examined using environmental scanning electron microscopy (ESEM). The TPC content was found to be 15.63 ± 0.21 mg gallic acid/g dry matter, and the DPPH radical inhibition rate was 84.26 ± 1.35%. CH exhibited a significant inhibitory effect against Escherichia coli, and a moderate inhibition effect against Shigella flexneri, Salmonella spp., Salmonella typhimurium, and Escherichia coli EPEC. Finally, successful encapsulation of CH was achieved using sodium alginate, resulting in bead sizes ranging between 1.75 and 2.75 mm.

Green synthesis of ZnO/Fe3O4 nanoparticles with nigella sativa extract: Efficient degradation of methylene blue and antimicrobial properties

Zinc oxide (ZnO), iron oxide (Fe3O4) NPs, and ZnO/Fe3O4 nanocomposites (NCs) were synthesized using Nigella sativa (NS) seed extracts. These nanomaterials (NMs) were characterized by multiple analytical techniques like UV-visible spectrophotometers, FTIR spectroscopy, SEM, and XRD spectroscopy. The UV-visible spectrum showed 364 nm, 330 nm, and 331nm for ZnO NPs, Fe3O4 NPs, and ZnO/Fe3O4 NCs, respectively. Moreover, it was confirmed when the samples were run through FTIR techniques, and it was observed that the availability of bioactive functional groups was involved in the decline of bulk compounds to NPs. XRD showed their average nanoparticle size based on applying the formula of full width at half maximum (FWHM) for ZnO NPs, Fe3O4 NPs, and ZnO/Fe3O4 NCs at 29.52 nm, 22.08 nm, and 12.82 nm, respectively. In this study, the reduction of Methylene Blue (MB) dye was done by NPs and NCs, and their catalytic activities were investigated by a UV-visible spectrophotometer. MB dye showed the maximum absorption peak at 664 nm, and the reaction of MB was reduced using synthesized products with an accompanying color change reaction from blue to colorless within 60 min at 84%, 86%, and 99.5% degradation for ZnO NPs, Fe3O4 NPs, and ZnO/Fe3O4 NCs with rate constants of 0.00035, 0.00065, and 0.0015 Lmol-1S-1. The 2nd order rate constant was observed in this study. The agar disc diffusion method was used to investigate the potential antibacterial activity of synthesized NPs and NCs. This study is best suited for Gram-positive bacteria. NS seed extract-based synthesis of NCs could be an excellent catalyst and biological application for environmental pollution.

Evaluating the Antibacterial and Anti‐Biofilm Properties of Chitosan Nanoemulsion Containing Euphorbia hebecarpa Plant Extract Against Escherichia coli and Staphylococcus aureus

ABSTRACTThe use of nanoparticles as drug‐carrying systems in medicine has received much attention, and on the other hand, the use of plants with medicinal properties has advantages over synthetic drugs. This study aims to improve the antibacterial and anti‐biofilm properties of Euphorbia hebecarpa plant extract using chitosan nanoparticles. Extraction were performed using the modified maceration and methanol solvent. The agar disc diffusion method was carried out to investigate the antimicrobial effects and MIC at an optical density (OD) of 630 nm. The anti‐biofilm agent's influence was measured at OD 570 nm, and the metabolic activity of bacteria in the damaged biofilm was determined using triphenyl tetrazolium chloride (TTC) staining. The nanoparticles were obtained by following the ionic gelation method and its characteristics were evaluated. Chitosan nanoparticles loaded with plant extract were found to be spherical shape with hydrodynamic diameter of 142 nm, a polydispersity index (PDI) of 0.184, a zeta potential of +28.6 mV. It was determined that the loading capacity (% LC) and encapsulation efficiency (% EE) percentages were 33% and 40%, respectively. The diameter of the inhibition zone in the agar disc diffusion test for both bacteria using nanoparticles loaded with the extract increased compared with control groups. Also, at a concentration of 4 mg/mL of loaded nanoparticles, 49.33% of Escherichia coli biofilm and 62.7% of Staphylococcus aureus biofilm were destroyed. The data obtained from the tests performed in this study show that the use of Euphorbia plant extract in the form of chitosan nanoparticles can have more antimicrobial and anti‐biofilm effects.

Phytochemical Characterization and Synergistic Antibacterial Effects of Colebrookea Oppositifolia Essential Oil as Adjuvants to Modern Antibiotics in Combating Drug Resistance.

The global threat of multi-drug-resistant bacteria has severely limited the options available for effective antibiotics. This study focuses on the antimicrobial activity and phytochemical characterization of C. oppositifolia extracts, aiming to identify novel plant-based therapeutic agents. C. oppositifolia specimens-leaves and inflorescence. Specimens were cleaned, sterilized, dried, and ground into a fine powder. Extracts were obtained using methanol and petroleum ether via a Soxhlet apparatus, followed by fractionation with chloroform, n-butanol, and ethyl acetate. Volatile oil was extracted through hydro distillation using a Clevenger apparatus. Phytochemical analysis was conducted to identify bioactive compounds. Biophysical techniques, including UV-visible spectrophotometry, TLC, HPLC, GC-MS, FTIR, and NMR, were employed for characterization. Antimicrobial activity was tested against S. aureus ATCC25922 and E. coli ATCC25922 using agar well and disc diffusion methods, and synergistic effects were assessed with erythromycin and amoxicillin. Methanol extract exhibited bacteriostatic activity with inhibition zones of 13.0 ± 0.2 mm for both S. aureus and E. coli. Petroleum ether, chloroform, n-butanol, and ethyl acetate fractions showed varying inhibition zones. Erythromycin demonstrated bactericidal activity, which was enhanced synergistically when combined with methanol extract and volatile oil, increasing inhibition zones against S. aureus. Phytochemical analysis identified phenols, flavonoids, tannins, coumarins, alkaloids, terpenoids, saponins, and glycosides. FTIR analysis revealed functional groups such as amines, aldehydes, nitriles, alkenes, and sulfones. GC-MS identified 24 compounds, with α-pinene, caryophyllene, and carene as major components. NMR spectra indicated no complex formation between oils and antibiotics, suggesting the compounds act as synergists. The C. oppositifolia extracts possess significant antimicrobial activity and synergistic potential, particularly against S. aureus. The presence of various bioactive compounds suggests a promising role in developing new plant-based therapeutics.

Magnesium borate-glasses for biomedical application: Physicochemical and in vitro bioactive properties, antibacterial activity and cell viability

Borate bioactive glasses doped with magnesium oxide (MgO) were synthetized by melt-quenching method and evaluated their physicochemical and in vitro bioactive properties. The glasses were characterized by volumetric density, DTA, XRD and FTIR techniques. In vitro bioactivity was evaluated by SBF immersion test. Cytocompatibility tests were performed on RAW-247 murine macrophage cells. Antibacterial activity was evaluated by the agar disk diffusion method. The XRD results confirm the amorphous nature of the glasses. FTIR analysis showed that the MgO addition modifies the glass network, causing changes in the volumetric density, molar volume, and thermal properties. The in vitro bioactivity was confirmed by XRD, FTIR, and SEM-EDS analyses; all samples showed the formation of biological apatites. All samples are non-cytotoxic and presented good antibacterial activity against S. aureus and P. aeruginosa bacteria. Therefore, all samples are good candidates for biomedical applications, mainly in bone regeneration.