Minimum Bactericidal Concentration Research Articles

Magnetic separation, sunlight-driven photocatalytic activity, and antibacterial studies of Sm-doped Co0.33Mg0.33Ni0.33Fe2O4 nanoparticles.

Magnetic nanoparticles have emerged as a promising tool for wastewater treatment due to their unique properties. In this regard, Co0.33Mg0.33Ni0.33SmxFe2-xO4 (0.00 x 0.08) nanoparticles were prepared to examine their magnetic separation efficiency (MSE), photocatalytic, antibacterial, and antibiofilm performances. Pure nanoparticles, having the highest saturation magnetization (Ms = 31.87emu/g), exhibit the highest MSE, where 95.6% of nanoparticles were separated after 20min of applying a magnetic field of 150 mT. The catalytic performance of the prepared samples is examined by the photodegradation of rhodamine B (RhB) dye exposed to direct sunlight radiation. Improved photocatalytic activity is exhibited by Co0.33Mg0.33Ni0.33Sm0.04Fe1.96O4 nanoparticles, labeled as Sm0.04, where the rate of the degradation reaction is enhanced by 4.1 times compared to pure nanoparticles. Rising the pH and reaction temperature improves the rate of the photodegradation reaction of RhB. The incorporation of 15 wt% reduced graphene oxide (rGO) with Sm0.04 enhanced the rate of the reaction by 1.7 and 2.4 times compared with pure Sm0.04 sample and rGO, respectively. The antibacterial and antibiofilm activities against Escherichia coli, Leclercia adecarboxylata, Staphylococcus aureus, and Enterococcus faecium are assessed by the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) broth microdilution, the agar well diffusion, the time-kill assays, the biofilm formation, and destruction assays. The bacteria used in these assessments are isolated from wastewater. The nanoparticles exhibit a bacteriostatic activity, with a better effect against the Gram-positive isolates. Co0.33Mg0.33Ni0.33SmxFe2O4 (x = 0.00) nanoparticles have the best effect. The effect is exerted after 2-3h of incubation. Gram-positive biofilms are more sensitive to nanoparticles.

Unraveling the antimicrobial activity of nutmeg and turmeric essential oils against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella spp.

The consumer demand for a reduction in the use of synthetic additives in food has been providing a greater search and incentive for the food industries to use new alternatives for food preservation. Among them, there is the initiative to use essential oils (EOs) due to their antimicrobial properties, coming from specific compounds in their compositions. However, in view of limitations related to the use of EOs, as well as their susceptibility to oxidation and degradation, the possibility arises of employing protection methods such as microencapsulation to minimize the impairment of the benefits associated with the application of EOs. This study aimed to examine the antimicrobial effect of turmeric and nutmeg EOs against microbial strains of Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella spp., as well as the microparticles of the EOs involved. Analyses of the minimum inhibitory concentration (MIC), the minimum bactericidal concentration (MBC), and the developed microparticles, as well as the verification of the synergistic inhibitory action between these oils, were carried out. For free oils, antimicrobial action was evidenced against the vast majority of microorganisms tested, with free nutmeg EO having a better antimicrobial effect than free turmeric oil. In contrast, for encapsulated oils, only antimicrobial action was noted against strains of Listeria. Furthermore, the synergism of free oils did not potentiate the antimicrobial action. Regarding the alternative of microencapsulation of EOs, it was obtained that the results in which chitosan was used as wall material were more promising than when gelatin was used as wall material.

In vitro assessment of the effect of magnetic fields on efficacy of biosynthesized selenium nanoparticles by Alborzia kermanshahica

Cyanobacteria represent a rich resource of a wide array of unique bioactive compounds that are proving to be potent sources of anticancer drugs. Selenium nanoparticles (SeNPs) have shown an increasing potential as major therapeutic platforms and led to the production of higher levels of ROS that can present desirable anticancer properties. Chitosan–SeNPs have also presented antitumor properties against hepatic cancer cell lines, especially the Cht-NP (Chitosan–NPs), promoting ROS generation and mitochondria dysfunction. It is proposed that magnetic fields can add new dimensions to nanoparticle applications. Hence, in this study, the biosynthesis of SeNPs using Alborzia kermanshahica and chitosan (CS) as stabilizers has been developed. The SeNPs synthesis was performed at different cyanobacterial cultivation conditions, including control (without magnetic field) and magnetic fields of 30 mT and 60 mT. The SeNPs were characterized by uv-visible spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), Dynamic light scattering (DLS), zeta potential, and TEM. In addition, the antibacterial activity, inhibition of bacterial growth, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC), as well as the antifungal activity and cytotoxicity of SeNPs, were performed. The results of uv-visible spectrometry, DLS, and zeta potential showed that 60 mT had the highest value regarding the adsorption, size, and stabilization in compared to the control. FTIR spectroscopy results showed consistent spectra, but the increased intensity of peaks indicates an increase in bond number after exposure to 30 mT and 60 mT. The results of the antibacterial activity and the inhibition zone diameter of synthesized nanoparticles showed that Staphylococcus aureus was more sensitive to nanoparticles produced under 60 mT. Se-NPs produced by Alborzia kermanshahica cultured under a 60 mT magnetic field exhibit potent antimicrobial and anticancer properties, making them a promising natural agent for use in the pharmaceutical and biomedical industries.

Innovative optimization for maximum magnetic nanoparticles production by Trichoderma asperellum with evaluation of their antibacterial activity, and application in sustainable dye decolorization

A pioneer microbial-based synthesis of various nanoparticles is gaining more attention due to their potent applications in various industries. The magnetic nanoparticles (M-nps) were fabricated for the first-time using the cell free extract of Trichoderma asperellum. The M-nps bioprocess optimization was performed using Response Surface Methodology and Artificial Neural Network.The bioprocess was significantly (P < 0.05) affected by pH, stirring speed, and incubation period. The M-nps displayed a strong antibacterial efficiency against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus in a dose-dependent manner. The minimum inhibitory concentration (MIC) for E. coli, P. aeruginosa, and S. aureus were respectively found to be 25.0, 6.25, and 3.125 µg/ml. While the minimum bactericidal concentration (MBC) was 25.0, 12.5, and 6.25 µg/ml. The highest inhibition zone of 22 mm was recorded for B. subtilis at 80 µg/ml with MIC and MBC of 3.125 µg/ml. The sodium alginate/M-nps microbeads was successfully prepared without any crosslinkers. The microbeads exhibited the highest adsorptive efficiency (84.32%) for malachite green at pH 8.0, dose 0.1 g, and time 60 min. The experimental data were superlative fitted to Langmuir’s isotherm, hinting monolayer adsorption of MG molecules with 117.65 mg g‐−1 adsorptive capacity. The regenerated beads continued up-to six consecutive cycles and maintained more than 90%, indicating the multiple time use of the prepared material. Hence, the green magnetic nanoparticles display promising application in combating bacterial pathogens. The magnetic microbeads can be employed as an alternative eco-friendly, highly efficient, sustainable, and low-cost biosorbent in removing contaminants from wastewater.

Antimicrobial activity of Cinnamomum zeylanicum essential oil against colistin-resistant gram-negative bacteria

ABSTRACT In the current study, we evaluated the antimicrobial activity of Cinnamomum zeylanicum Blume essential oil (Cinn-EO) against a group of thirteen clinical colistin-resistant Gram-negative bacteria, including Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The GCMS analysis showed that cinnamaldehyde was the major compound (94.29%) of the Cinn-EO. The diameter of the inhibition zone by Cinn-EO varied from 24 to 37 mm. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values ranged between 0.625 and 5 mg/mL. Interestingly, the MBC/MIC was equal to 1 for most tested bacterial strains, indicating an advanced bactericidal effect of Cinn-EO against colistin-resistant Gram-negative bacteria. The absorption, distribution, metabolism, elimination, and toxicity (ADMET) prediction showed good pharmacokinetic properties of the tested cinnamaldehyde. The results suggest that cinnamaldehyde could be a potential alternative to treat infection caused by colistin-resistant Gram-negative bacteria.

Efficacy of a mouthwash containing ε-poly-L-lysine, funme peptides and domiphen in reducing halitosis and supragingival plaque: a randomized clinical trial

ObjectiveTo evaluate the antibacterial effectiveness of a combination of ε-poly-L-lysine (ε-PL), funme peptide (FP) as well as domiphen against oral pathogens, and assess the efficacy of a BOP® mouthwash supplemented with this combination in reducing halitosis and supragingival plaque in a clinical trial.Materials and methodsThe minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the compound against Fusobacterium nucleatum, Porphyromonas gingivalis, Streptococcus mutans, and Aggregatibacter actinomycetemcomitans were determined by the gradient dilution method. Subsequently, the CCK-8 assay was used to detect the toxicity of mouthwash on human gingival fibroblastst, and the effectiveness in reducing halitosis and supragingival plaque of the mouthwash supplemented with the combination was analyzed by a randomized, double-blind, parallel-controlled clinical trial.ResultsThe combination exhibited significant inhibitory effects on tested oral pathogens with the MIC < 1.56% (v/v) and the MBC < 3.13% (v/v), and the mouthwash containing this combination did not inhibit the viability of human gingival fibroblasts at the test concentrations. The clinical trial showed that the test group displayed notably lower volatile sulfur compounds (VSCs) at 0, 10, 24 h, and 7 d post-mouthwash (P < 0.05), compared with the baseline. After 7 days, the VSC levels of the and control groups were reduced by 50.27% and 32.12%, respectively, and notably cutting severe halitosis by 57.03% in the test group. Additionally, the Plaque Index (PLI) of the test and control group decreased by 54.55% and 8.38%, respectively, and there was a significant difference in PLI between the two groups after 7 days (P < 0.01).ConclusionsThe combination of ε-PL, FP and domiphen demonstrated potent inhibitory and bactericidal effects against the tested oral pathogens, and the newly formulated mouthwash added with the combination exhibited anti-dental plaque and anti-halitosis properties in a clinical trial and was safe.Trial registrationThe randomized controlled clinical trial was registered on Chinese Clinical Trial Registry (No. ChiCTR2300073816, Date: 21/07/2023).

Chemical composition and biological activities of essential oils of seven Cultivated Apiaceae species

The Apiaceae family contains many species used as food, spice and medicinal purposes. Different parts of plants including seeds could be used to obtain essential (EO) oils from members of the Apiaceae family. In the present study, EOs were components obtained through hydrodistillation from the seeds of anise (Pimpinella anisum), carrot (Daucus carota), celery (Apium graveolens), dill (Anethum graveolens), coriander (Coriandrum sativum), fennel (Foeniculum vulgare), and cumin (Cuminum cyminum). EO constituents were determined with Gas Chromatography/Mass Spectrometry (GC–MS) and Gas Chromatography/Flame Ionization Detector (GC-FID) and their antioxidant capacities were determined with the cupric reducing antioxidant capacity (CUPRAC) and 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) methods. The antimicrobial activity of EOs were tested against four pathogenic bacteria. Phenylpropanoids in anise (94.87%) and fennel (92.52%), oxygenated monoterpenes in dill (67.59%) and coriander (98.96%), monoterpene hydrocarbons in celery (75.42%), mono- (45.42%) and sesquiterpene- (43.25%) hydrocarbons in carrots, monoterpene hydrocarbon (34.30%) and aromatic hydrocarbons (32.92%) in cumin were the major compounds in the EOs. Anethole in anise and fennel, carotol in carrot, limonene in celery, carvone in dill, linalool in coriander, and cumin aldehyde in cumin were predominant compounds in these EOs. The high hydrocarbon content in cumin EO gave high CUPRAC activity (89.07 µmol Trolox g−1), and the moderate monoterpene hydrocarbon and oxygenated monoterpene content in dill EO resulted in higher DPPH activity (9.86 µmol Trolox g−1). The in vitro antibacterial activity of EOs against Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli was evaluated using the agar diffusion method and the minimum bactericidal concentration was determined. Coriander, cumin and dill EOs showed inhibitory effect against all tested strains except P. aeruginosa. While fennel and celery EOs were effective against E. coli and B. cereus strains, respectively, anise and carrot EOs did not show any antibacterial effect against the tested bacteria. Hierarchical Cluster Analysis (HCA) produced four groups based on EO constituents of seven species. The potential adoption of the cultivated Apiaceae species for EO extraction could be beneficial for the wild species that are endangered by over collection and consumption.

Photo-sensitive Antibacterial Activity of o-Phenylenediamine Carbon Dots

Carbon dots (CDs) are among the famous nanoparticles that have been widely developed due to high biocompatibility, low toxicity, ease of preparation, excellent photoluminescent properties, and outstanding application in biomedicine. Among the various biomedical activities of CDs, they can be applied as antibacterial agents because of their photodynamic properties. Photodynamic therapy (PDT) has been considered an alternative antibacterial agent because of its non-invasive nature and minimal side effects, especially in terms of improving antibacterial activity against multidrug resistant bacteria when compared with traditional antibiotics. In this research, we developed CDs from o-phenylenediamine (OP). The o-phenylenediamine CDs (OPCDs) were synthesized via a hydrothermal method at 180°C for 3 h. After that, they revealed a spherical shape with a size range of 16.38 ± 2.64 nm. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of OPCDs against Staphylococcus aureus (S. aureus) for both light exposure and without light exposure groups were significantly greater than the OP solution because the OPCDs could generate reactive oxygen species (ROS) via a photodynamic mechanism leading to the bacteria cell death. Therefore, the created OPCDs may have the capability to be utilized for treating skin infections caused mainly by S. aureus. In conclusion, OPCDs could be proposed as nanomaterials that enhance antibacterial activity and provide photodynamic properties.

Assessment of in vitro Anti-inflammatory and Anti-acne-inducing Bacterial Activities of Kameng (Eclipta prostrata Linn.) Cultivated in Suphan Buri Province, Thailand

This research investigates extracts from Kameng (Eclipta prostrata Linn.), originally employed in traditional medicinal recipes, with the aim of developing an extract that can serve as an alternative to antibiotics. For this purpose, the anti-inflammatory and anti-acne-inducing bacterial activities of Kameng crude ethanol extract, grown in Suphan Buri Province were investigated, with anti-inflammatory properties assessed by the inhibition of protein degradation and proteinase inhibitory assays. Findings indicated the potential of Kameng extracts as anti-inflammatory drugs that reduce protein degradation and proteinase activities. Kameng extract concentrations ranging from 0.4 to 4.0 x 104 ppm inhibited protein degradation and proteinase activity by 14.66%-50.75% and 28.57%-72.08%, respectively. The agar disc diffusion method revealed that Kameng extracts had strong inhibitory effects against S. aureus and C. acnes, with inhibition zone diameters of 31.15±0.47 and 37.28±0.47 mm, respectively. The minimal inhibitory concentration (MIC) of Kameng extract against S. aureus and C. acnes was 5.0 mg/mL and 2.5 mg/mL while minimal bactericidal concentration (MBC) of Kameng extract against S. aureus and C. acnes was 20.0 mg/mL and 10.0 mg/mL, respectively. Results suggested the potential of Kameng extract to cure acne and skin inflammation as a herbal cosmetic product.

Evaluation of phytochemical, in vitro antibacterial and rate of kill assay of &lt;i&gt;Terminalia avicennioides&lt;/i&gt; leaf against some bacteria associated with diarrhoea

The study was aimed to evaluate the phytochemical constituents, in vitro antibacterial and rate of kill assay of Terminalia avicennioides leaf extract against some bacteria associated with diarrhoea. The phytochemical constituents of the ethanol of Terminalia avicennioides leaf, aqueous, n- butanol, and ethyl acetate fractions of the leaf extract were determined using standard analytical methods. The antibacterial activities of the leaf extract and extract fractions against clinical isolates of Salmonella Typhimurium and Escherichia coli isolated from diarrhoeaic patients were determined in vitro by agar diffusion, dilution and time - kill methods. The result of phytochemical screening revealed the presence of carbohydrates, cardiac glycosides, saponins, flavonoides, tannins, alkaloids, phenols and triterpenes. The crude extract and extract fractions of T. avicennioides leaf were effective against the test bacterial isolates at varied concentration of extracts but the n-butanol fraction was more effective with Minimum inhibitory and Minimum Bactericidal Concentration of 6.25 and 12.5mg/ml. The clinical isolates of E. coli and S. Typhimurium were completely killed within 180 minutes of exposure to ethanol leaf extract and extract fractions at varied MBCs of 12.5 mg/ml and 25.0 mg/ml. The clinical isolates of E. coli and S. Typhimurium were more susceptible to n-butanol fraction within 120 minutes of exposure to the extract fraction.

Niosome gels encapsulate green mangosteen peel extract (Garcinia mangostana L.) as an anti-acne-inducing bacterial and anti-inflammatory activity

This research aims to develop a niosome gel from green mangosteen peel extract (Garcinia mangostana L.) by maceration with an ethanol solvent. The result of the yield percentage was 14.35 ± 0.90. The result of analyzing the phytochemicals by high-performance liquid chromatography (HPLC) was that tannin and xanthone were equal to 0.7483 ± 0.0825 mg per 100 mg of extract and 0.02964 ± 0.0088 mg per 100 mg of extract, respectively. The results of the determination of the effect include anti-inflammatory and anti-bacterial (Cutibacterium acnes) as anti-inflammatory with nitric oxide from LPS-induced macrophage cells up to a maximum equal to 29.10 ± 4.78% as a concentration at 1 mg mL–1 as acetonide can inhibit nitric oxide equal to 33.12 ± 3.62% as a concentration at 1 mg mL–1. and anti-bacterial (Cutibacterium acnes) by broth microdilution and drop plate methods, it was found that clindamycin has a minimum inhibitory concentration (MIC) and a minimum bactericidal concentration (MBC) of 0.08 μg mL–1 and 0.31 μg mL–1, respectively. The development of niosomes consisting of cholesterol, tween 60, and mangosteen peel extract at 1% w w–1 and 2% w w–1 in every formula showed good stability. The reduction of particle size in the formula by an ultrasonic bath at 30 minutes and measurement of particle size with a transmission electron microscope (TEM) were found to be equal to 1,265 and 123 – 219 nm, respectively. The polydispersity index (PDI) was in the range of 0.1 – 0.2, and the zeta potential value was in the range of –26.15 to –28.61 mV. The result of hydration and trans epidermal water loss (TEWL) was found to be that after 4 weeks of use, the formula containing the niosomes of mangosteen peel extract concentrated at 2% w w–1 maximizes skin moisture. It has a value of 346 ± 39.27 and has the least surface water loss. GRAPHICAL ABSTRACT HIGHLIGHTS The green mangosteen peel extract (Garcinia mangostana L.) can inhibiting nitric oxide production from LPS-induced macrophage cells up to 29.10  ± 4.78% at a concentration of 1 mg ml-1, the lowest inhibitory (MIC)  and kill (MBC) concentration of C. acnes bacteria less than 0.24 mg ml-1. The particle size of niosomes encapsulate extracts before reducing particle size equal to 1,265 nm. and after reducing particle size in the range of 123 - 219 nm. The skin hydration value after using product for 4 weeks as niosome gel encapsulate extract 2%w w-1 of extract was maximum moisture and minimal water loss.

Bio-functional properties and phytochemical composition of selected Apis mellifera honey from Africa

Globally, the demand for natural remedies such as honey to manage ailments has increased. Yet, the health benefits and chemical composition of African honeys are not yet well understood. Therefore, this study aimed to characterise the bio-functional properties and the phytochemical composition of 18 Apis mellifera honeys from Kenya, Uganda, and Cameroon in comparison to the popular and commercially available Manuka 5+ honey from New Zealand. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay (DPPH-RSA) assay was used to determine the antioxidant property, whilst the agar well diffusion and broth dilution (Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)) assays were used to determine antimicrobial property. Colorimetric methods were used for phytochemical analysis. Our results showed that honeys collected from Rift Valley region of Kenya (e.g. Poi, Salabani and Mbechot) and Western region of Cameron (e.g. Bangoulap) had the highest antioxidant (DPPH RSA of 41.52-43.81%), antimicrobial (MIC (3.125-6.25% w/v) and MBC (6.25-12.5% w/v)) activities. Additionally, the total flavonoid (770-970 mg QE/100 g), phenol (944.79-1047.53 mg GAE/100 g), terpenoid (239.78 -320.89 mg LE/100 g) and alkaloid (119.40-266.57 mg CE/100 g) contents reached the highest levels in these bioactive African honeys, which significantly and positively correlated with their bio-functional properties. The functional and phytochemical composition of these bioactive African honeys were similar to or higher than those of the Manuka 5+ honey. Furthermore, gas chromatography-mass spectrometry analysis of African honeys revealed 10 most prominent volatile organic compounds that contribute to their geographical distinction: triacontane, heptacosane, (Z)-9-tricosene, tetracosane, 6-propyl-2,3-dihydropyran-2,4-dione, octacosane, 1,2,4-trimethylcyclohexane, 1,3-bis(1,1-dimethylethyl) benzene, 2-methylheptane and phytol. Overall, our findings suggest that some of the tested African honeys are natural sources of antimicrobial and antioxidant therapies that can be exploited upon further research and commercialized as high value honey.

The antimicrobial effectiveness of Rosmarinus officinalis, Lavandula angustifolia, and Salvia officinalis essential oils against Klebsiella pneumoniae and Pseudomonas aeruginosa in vitro and in silico

This study aimed to explore the phytochemical analyses and antibacterial potential of three essential oils (EOs) using both in-vitro and in-silico experiments for drug discovery. The Eos of Rosmarinus officinalis, Lavandula angustifolia, and Salvia officinalis were extracted by hydrodistillation, and GC–MS determined the chemical composition. The antibacterial activities of each EO were studied by the disc diffusion method. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of these EOs were determined by micro-dilution. In addition, the EOs were combined with ineffective antibiotics (Aztreonam et al.) against clinical bacteria (P. aeruginosa and K. pneumoniae) to determine this association's effect. The in-vitro toxicological study was based on the MTT cytotoxicity assay. Finally, in-silico methods were employed to estimate their possible antibacterial mechanisms. Molecular docking was performed to calculate the predictive binding affinities of five major volatile components to three proteins key in the bacterial cycle using the AutoDock Vina program; prediction of drug-likeness properties and Toxicity prediction were carried out respectively by SwissADME and ProToxII online server. The results showed that the three EOs possessed antibacterial activity against ATCC and clinical K. pneumoniae. We note that P. aeruginosa was resistant to lavender and sage EOs. Surprisingly, adding EOs to antibiotics ineffective against resistant bacteria showed a significant synergistic antibacterial effect. Cytotoxicity assay of essential oils showed different values ranging from 0.22 to 0.43 µL/mL. Finally, the molecular docking study revealed that both compounds (1,8-Cineol, 1-Dodecene, Linalool, cis-Thujone, and Camphor) from the three EOs have a significant potential to inhibit the protein target involved in bacteria resistance. Furthermore, the SwissADME prediction results showed that all five components satisfy the rule of five and exhibit acceptable drug-like characteristics. findings suggest that the three EOs have interesting antibacterial activity. The in-vitro and in-silico studies gave a great potentiation and may constitute a promising option to control the emergence of MDR P. aeruginosa and K. pneumoniae.

Antibacterial activity of Angelica essential oil, its mechanism against Pseudomonas fluorescens, and its application in the preservation of chilled fresh beef

The mechanism by which Angelica essential oil (AEO) can act as an antimicrobial agent at cellular and metabolic levels to inhibit Pseudomonas fluorescens (P. fluorescens), and its effectiveness in beef preservation, were investigated and evaluated in this study. Our results showed that the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of AEO to P. fluorescens were 12.5 μL/mL and 25 μL/mL, respectively, at which AEO could effectively inhibit P. fluorescens reproduction and retard its growth (p < 0.05). Severe morphological damage to the AEO-treated cells of the microorganism, including cell walls and membranes, were observed via scanning electron microscopy (SEM). AEO treatment was also seen to lead to an increase in alkaline phosphatase (AKPase) activity and conductivity, and a significant leakage of intracellular macromolecular components (such as nucleic acids and proteins), providing further evidence of damage to the integrity of cell wall and cell membrane. Metabolomics analysis revealed that the differential metabolites in the AEO hindered nucleic acid synthesis and expression in the P. fluorescens, leading to tricarboxylic acid (TCA) cycle blockage and amino acid restriction, energy metabolism disorders and membrane damage, mainly through nucleotide metabolism, amino acid metabolism, carbohydrate metabolism and membrane transport. Moreover, application testing demonstrated the efficacy of AEO in slowing the increase of beef pH and total volatile basic nitrogen (TVB-N), extending the shelf life of chilled beef by 5.39 d, and effectively maintaining the organoleptic quality of beef. These results lay a foundation for the development of AEO as a natural bacteriostatic agent.

Antimicrobial and antioxidant activities of lignin by-product from sugarcane leaf conversion to levulinic acid and hydrochar

To enhance the sustainability of lignocellulosic biomass utilization process, a significant attention is given to a high-value lignin byproduct of this process. Herein, antimicrobial, antioxidant, and physicochemical properties of lignin in black liquor extracted from sugarcane leaf (SCL) for levulinic acid (LA) and hydrochar production were investigated. The lignin was extracted from SCL through an alkaline pretreatment process using 5–25 wt% of either NaOH or KOH at 120–160 °C. Disk diffusion susceptibility tests, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) revealed that the SCL lignin is effective against Gram-positive bacteria (S. aureus) rather than Gram-negative bacteria (E. coli and S. typhimurium). Different alkaline reagents marginally affected the antimicrobial and antioxidant activities of the lignin. Py-GC/MS analysis results determined that the SCL lignin contained mainly p-hydroxyphenyl (H) and guaiacyl (G) with a small amount of syringyl (S) lignin. Furthermore, the structural alterations and linkages of SCL lignin during alkaline pretreatment were examined using 2D-HSQC NMR, providing valuable insights into the transformation processes. The conversion of delignified SCL to LA through a catalytic hydrothermal process using various acid catalysts indicated that the alkaline pretreatment could enhance LA yield with a maximum yield of 33.4 wt%. Additionally, fuel property characterization of the hydrochar co-product from LA production determined that the hydrochar can be used as a coal substitute.

Antibacterial and antibiofilm activities of selenium nanoparticles-antibiotic conjugates against anti-multidrug-resistant bacteria

The crucial demand to overcome the issue of multidrug resistance is required to refine the performance of antibiotics. Such a process can be achieved by fastening them to compatible nanoparticles to obtain effective pharmaceuticals at a low concentration. Thus, selenium nanoparticles (Se NPs) are considered biocompatible agents that are applied to prevent infections resulting from bacterial resistance to multi-antibiotics. The current evaluated the effectiveness of Se NPs and their conjugates with antibiotics such as amikacin (AK), levofloxacin (LEV), and piperacillin (PIP) against Pseudomonas aeruginosa (P. aeruginosa). In addition, the study determined the antibacterial and antibiofilm properties of Se NPs and their conjugates with LEV against urinary tract pathogens such as Staphylococcus aureus (S. aureus), Enterococcus faecalis (E. faecalis), P. aeruginosa, and Escherichia coli (E. coli). The result of minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) for eight isolates of P. aeruginosa revealed that the conjugation of Se NPs with AK, LEV, and PIP resulted in a reduction in the concentration of antibiotic-conjugated Se NPs. The concentration was found to be about 10–20 times lower than that of bare antibiotics. The MIC of the Se NPs with LEV (i.e., Se NPs:LEV) for S. aureus, E. faecalis, P. aeruginosa, and E. coli was found to be 1.4:0.5, 0.7:0.25, 22:8, and 11:4 µg/mL, respectively. The results of the half-maximal inhibitory concentration (IC50) demonstrated that Se NPs:LEV conjugate have inhibited 50 % of the mature biofilms of S. aureus, E. faecalis, P. aeruginosa, and E. coli at a concentration of 27.5 ± 10.5, 18.8 ± 3.1, 40.6 ± 10.7, and 21.6 ± 3.3 µg/mL, respectively compared to the control. It has been suggested that the antibiotic-conjugated Se NPs have great potential for biomedical applications. The conjugation of Se NPs with AK, LEV, and PIP increases the antibacterial potency against resistant pathogens at a low concentration.

ANTIBACTERIAL AND ANTIFUNGAL ACTIVITIES OF SOME HYDRAZONES SYNTHESIZED FROM NICOTINIC ACID HYDRAZIDE

N’-(2-pyridinylmethylene)nicotinohydrazide A, N’-(4-pyridinylmethylene)nicotinohydrazide B, N’-(2- ethoxybenzylidene)nicotinohydrazide C, N’-(4- ethoxybenzyldene)nicotinohydrazide D and N’-(2-hydroxyl-5-methoxybenzylidene)nicotinohydrazide E, was prepared by refluxing the ethanolic solution of nictonic acid hydrazide and ethanolic solutions of 2-pyridinrcarboxaldehyde, 4-pyridinecarboxaldehyde, 2-ethoxybenzaldehyde, 4-ethoxybenzaldehyde and 2-hydroxy-5-methoxybenzaldehyde in 1:1 mole ratio for 4 hours in a separate reactions. The compounds obtained had a melting point between (120-236 oC) and a percentage yield between (52.38-77.70 %). They were crystalline solids. The compounds' solubility were assessed in water, ethanol, methanol, acetone, hexane, diethyl ether, dimethyl sulfoxide (DMSO), ethyl acetate, and chloroform. The substances were discovered to be fully soluble in DMSO and methanol. FT-IR, 1H-NMR and 13C-NMR were used for the characterization of the compounds. The antibacterial and antifungal properties were tested against Methicillin-resistant Staphylococcus Aureus, Vancomycin-resistant Enterococci, S. aureus, S. typhi, P. aeruginosa, A. nigre, A. flavus, and C. albicans. The zones of inhibitions ranged from 22 to 28 mm and the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC) were found to be 0.063 mg/mL, 0.125 mg/mL and 0.125 mg/mL respectively. These indicated that the compounds might be good potential drug candidates.

THE EFFICACY OF COCOA BEAN EXTRACT MOUTHWASH CONCENTRATION IN REDUCING PLAQUE INDEX IN THE ORAL CAVITY AMONG PRIMARY SCHOOL STUDENTS AT SDN KAYEE LEU, INGIN JAYA SUBDISTRICT, ACEH BESAR

Oral and dental diseases have a high prevalence in Indonesia, with 88.8% of the population experiencing dental caries and periodontitis. Dental plaque is a soft deposit that tightly adheres to tooth surfaces and is composed of microorganisms that contribute to the development of dental caries. Preventing caries and controlling plaque can be achieved through the use of mouthwash, which is more effective when herbal mouthwash containing antioxidants and antibacterial agents is used. Cocoa bean extract (Theobroma Cacao L.) contains secondary metabolites such as alkaloids, flavonoids, tannins, steroids, and exhibits antibacterial and anti-inflammatory properties, as well as strong inhibitory effects against S. mutans bacteria. The objective of this study is to determine the effectiveness of cocoa bean extract mouthwash concentration in reducing the plaque index in the oral cavity. The research methods included laboratory experiments and quasi-experiments with a post-test only control group design. The research was conducted at the Faculty of Veterinary Medicine laboratory, University of Syiah Kuala, and SDN Kayee Leu, Aceh Besar, involving 30 students. Data analysis was performed using ANOVA in the SPSS program. The results of the study indicate that the phytochemical analysis of cocoa bean extract contains alkaloids, steroids, terpenoids, saponins, flavonoids, phenols, and tannins. The Minimum Inhibitory Concentration (MIC) of cocoa bean extract mouthwash on the growth of Streptococcus mutans was observed at a concentration of 1%, and no Minimum Bactericidal Concentration (MBC) was found in this study. The 1% and 2% concentrations of the mouthwash effectively removed plaque compared to the 0% concentration. In conclusion, the use of cocoa bean extract mouthwash is effective in reducing the plaque index. Further research should consider clinical trials to explore its potential as an herbal remedy.

Antimicrobial Activity, Cytotoxicity, and Qualitative Phytochemistry of Leaf, stem bark, and root bark extracts from Prunus africana (Hook. F.) Kalkman

The rise of resistant strains poses a significant public health risk, particularly, in sub-Saharan Africa, where over 50% of global infectious disease-associated deaths occur, highlighting the urgent need for novel, safe, affordable, and accessible antimicrobials. Accordingly, we investigated the antimicrobial activity, cytotoxicity, and qualitative phytochemistry of the aqueous, hydroethanolic, and acetonic leaf, stem bark, and root bark extracts of Prunus africana (Hook. F.) Kalkman, based on its ethnomedicinal information. The results showed the aqueous root bark and aqueous/acetonic stem bark extracts demonstrated significant (p&lt;0.05) antimicrobial efficacy against S. aureus at 800 µg/ml, outperforming other extracts and the reference antibiotic. Growth inhibition zones for most extracts on S. aureus showed a concentration-dependent increase, though not significantly (p&gt;0.05) different. The acetonic root bark extract, particularly at 800 µg/ml, exhibited superior inhibitory effects against B. cereus compared to other extracts (p&lt;0.05), although the positive control antibiotic significantly (p&lt;0.05) outperformed all plant extracts. Notably, none of the studied extracts affected P. aeruginosa and E. coli, while varying effects were observed against C. albicans. Further we observed that the hydroethanolic and aqueous stem bark extracts' exceptionally low Minimum Inhibitory and Bactericidal Concentrations (MICs and MBCs) against S. aureus (3.125 µg/ml). Conversely, the acetonic leaf extract showed higher MIC and MBC values against S. aureus (100 µg/ml). Cytotoxicity assessments using brine shrimp nauplii revealed the percentage mortalities caused by Vincristine and aqueous root/stem bark extracts at 1000 µg/ml, were significantly (p&lt;0.05) higher than those caused by other extracts (Median lethal concentrations (LC50) of 513 µg/ml to 24327.82 µg/ml). Qualitative phytochemistry identified alkaloids in root bark and stem bark extracts, flavonoids, phenols, quinones, steroids, and terpenoids across all samples, with saponins in acetonic root bark and all three leaf extracts, and glycosides in acetonic stem bark, hydroethanolic root bark, and acetonic leaf extracts. These findings highlight the diverse antimicrobial and cytotoxic properties of P. africana extracts, suggesting potential therapeutic applications and emphasise the need for further exploration.

Iron-Based Nanoparticles Synthesis, Characterization, and Antimicrobial Effectiveness

Background: Antimicrobial resistance (AMR) has emerged as a significant and pressing public health concern, posing serious challenges to effectively preventing and treating persistent diseases. Developing new antibiotics with different mechanisms of action is crucial to effectively address challenges in treating infections. A lot of work has already been done on mono-metallic nanoparticles to address the issue.Methods: This study aimed to synthesize multi-metallic iron, silver, and chitosan-embedded nanoparticles using a green approach. Iron, silver, chitosan nanoparticles, and a composite of iron–silver–chitosan was also synthesized. The synthesized nanoparticles and composites were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Fourier Transform Infrared Spectroscopy (FTIR) to evaluate their structural parameters. Their antimicrobial efficacy was investigated through MIC (minimum inhibitory concentration), MBC (minimum bactericidal concentration), and well-disk diffusion assays against Pseudomonas aeruginosa, Acinetobacter baumannii, Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans.Results: The size of the Cu-NPs, Cu-Ag NPs, and Cu-Ag-CS NPs were found to be in the range of 32-40 nm size with a spherical shape. The nanocomposites' MIC and MBC were calculated to be 125 μg/mL and 500 μg/mL, respectively. The nanocomposites exhibited a range of clear inhibition zones, with a minimum diameter of 12 ± 0.5 mm and a maximum diameter of 22 ± 0.5 mm. Conclusion: The iron–silver–chitosan nanocomposite has been shown to have significant antimicrobial effects in the laboratory environment compared to other nanoparticles hence can be applied as potential biomedical/biological candidates in future.Keywords: Antibacterial; Antifungal Agents; Iron; Silver; Chitosan; Nanoparticles