Optimal Antibacterial Activity Research Articles

Mn Single-Atom Nanozyme Functionalized 3D-Printed Bioceramic Scaffolds for Enhanced Antibacterial Activity and Bone Regeneration.

Infective bone defect is increasingly threatening human health. How to achieve the optimal antibacterial activity and regenerative repair of infective bone defect simultaneously is a huge challenge in clinic. Herein, this work reports a rational integration of Mn single-atom nanozyme into the 3D-printed bioceramic scaffolds (Mn/HSAE@BCP scaffolds). The integrated Mn/HSAE@BCP scaffolds can catalyze the conversion of H2 O2 to produce hydroxyl radical (• OH) and superoxide anion (O2 •- ) through cascade reaction. Besides, the prominent thermal conversion efficiency of Mn/HSAE@BCP scaffolds can be utilized for sonodynamic therapy (SDT). The synergetic strategy of chemodynamic therapy (CDT)/SDT enables the sufficient generation of reactive oxygen species (ROS) to kill Staphylococcus aureus (S. aureus) or Escherichia coli (E. coli). Furthermore, the enhanced antibacterial efficacy of Mn/HSAE@BCP scaffolds is beneficial to upregulate the expression of osteogenesis-related markers (such as collagen 1(COL1), Runt-related transcription factor 2 (Runx2), osteocalcin (OCN), and osteoprotegerin (OPG)) in vitro and further promote bone regeneration in vivo. The results demonstrate the good potential of Mn/HSAE@BCP scaffolds for the enhanced antibacterial activity and bone regeneration, which provide an effective method for the treatment of clinical infective bone defect.

Metabolit Profilling and Antibacterial Activity of Ethanol Extract of the Unripe Fruit Peel of Kayu Banana (Musa paradisiaca L. Var. Kayu)

According to Basic Health Research data in Indonesia in 2020 shows that the diarrhea morbidity rate in Indonesia is still high. In Indonesia, the unripe fruit of the Kayu banana (Musa paradisiaca L. var. Kayu) is a drug that is often used empirically by the people of Senduro village, Lumajang, East Java, Indonesia, to treat diarrhea. This study was conducted to investigate the antibacterial activity of unripe fruit peel, unripe fruit flesh and unripe fruit. A disc diffusion test was selected to assess the sensitivity of each sample to Escherichia coli. The disc dilution was used to determine the value of MIC and MBC in Escherichia coli. Total phenolic content to determine phenolic levels in samples that are suspected of providing antibacterial activity. Analysis of secondary metabolite profiles using the UPLC-Q-TOF/MS instrument. Unripe fruit peel extract shows more optimal antibacterial activity compared to other extracts. The diameter value of the inhibitory zone of the unripe fruit peel extract is 17 mm and the yield of a large ΔOD is –1.3620 at a concentration of 10 % w/v. Based on the calculation results from the regression equation, TPC fruit extract was obtained by 8.6 %, TPC flesh extracts by 6.1 % and TPC from bark extract by 10.8 %. Based on the data from the interpretation of compound content analysis using UPLC-QToFMS, it can be seen that there are 25 mayor compounds. These results suggest that the unripe fruit peel extract of banana Kayu has the potential to be antibacterial against Escherichia coli. The application of this research is as a reference for the development of antidiarrheal standardized herbal medicines and the implication of this research is to support the independence of national medicinal raw materials in Indonesia. HIGHLIGHTS Unripe fruit peel extract of Kayu banana (Musa paradisiaca var. Kayu) has the potential to be antibacterial against Escherichia coli. The results of this study showed that the peel extract of the unripe fruit of banana Kayu has an inhibitory zone diameter of 17 mm and there is a decrease in absorbance with a large ΔOD, which is 1.3620 with a total phenol content of 107.8 mg of gallic acid equivalent per gram of unripe fruit peel extract GRAPHICAL ABSTRACT

FORMULATION AND ACTIVITY TESTING OF RED ALGAE (Eucheuma cottonii) EXTRACT GEL AGAINST THE BACTERIA Propionibacterium acnes

Flavanoids are one of the many compounds in phenols that have the ability to denature bacterial cell membrane proteins, thus inhibiting cell growth. The purpose of this study was to formulate an anti-acne gel for the ethanolic extract of red algae (Eucheuma cottonii) and to test its antimicrobial activity against Propionibactericum acnes. The method used is laboratory research design by making antiacne gel preparations of red algae extract with concentrations of 1%, 3%, 5% and testing the antimicrobial activity with the agar diffusion method using wells on MHA media which is incubated for 1x24 hours. The results of the evaluation of the gel preparation before and after the cycling test met the requirements of organoleptic, homogeneity, pH, viscosity, and dispersibility where each formula was stable in the gel preparation. The results showed that red algae extract (Eucheuma cottonii) could be formulated and was stable in the form of an anti-acne gel and had antibacterial activity. In formula I with a concentration of 1% the inhibition zone formed was 36.33 mm, in formula II with a concentration of 3% the inhibition zone formed was 38.79 mm and in formula III with a concentration of 5% the inhibition zone formed was 34.27 mm. So that which has optimal antibacterial activity against Propionibacterium acnes is formula II with a concentration of 3% and an area of ​​inhibition zone of 38.79 mm

Study on secondary metabolites of endophytic fungus Diaporthe sp. AC1 induced by tryptophan analogs.

Small molecule-induced fermentation of the endophytic fungus Diaporthe sp. AC1 originated from Artemisia argyi was executed to investigate its secondary metabolites. It was fermented in a culture medium containing 5-hydroxytryptophan (5-HTP), 1-methyl-L-tryptophan (1-MT), and tryptamine (TA), respectively. The antibacterial activities of crude extracts against pathogenic bacteria and pathogenic fungi were determined by using the Oxford cup method, while the cytotoxicity of crude extracts against cancer cells was determined by using the MTT method. The results showed that the secondary metabolites of Diaporthe sp. AC1 induced by 1-MT exhibited optimal antibacterial activity and tumor cytotoxicity. The induction conditions of 1-MT were optimized, and the antibacterial activities and tumor cytotoxicity of crude extracts under different induction conditions were investigated. As indicated, the optimal moment for 1-MT addition was before inoculation and its optimal concentration was 0.25 mM. Under these conditions, Diaporthe sp. AC1 was fermented and approximately 12 g of crude extracts was obtained. The crude extracts were then separated and purified to acquire nine monomer compounds, including three new compounds (1-3) and six known compounds (4-9). The antibacterial activities of the compounds against pathogenic bacteria and pathogenic fungi were investigated by using the microdilution method, while their cytotoxicity against cancer cells was analyzed by using the MTT method. The results demonstrated that Compound 1 exhibited moderate antibacterial activities against Verticillium dahlia, Fusarium graminearum, and Botrytis cinerea, as well as a low inhibitory activity against Listeria monocytogenes. Nevertheless, Compound 1 showed significant cytotoxicity against five cancer cells, with IC50 ranging from 12.26 to 52.52 μM. Compounds 2 and 3 exhibited negligible biological activity, while other compounds showed detectable inhibitory activities against pathogenic bacteria and cancer cells.

Antibacterial and antivirulence factor activities of protein hydrolysates from Phatthalung Sangyod rice (Oryza sativa L.) seeds against zoonotic and foodborne pathogens.

Antimicrobial resistance is an emerging public health threat. Foodborne illnesses are typically caused by bacteria, such as Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, and Staphylococcus aureus, which are frequently resistant to common antimicrobial agents. Rice is a staple grain in most parts of the world. Our previous work showed that Phatthalung Sangyod rice seed protein hydrolysates (SYPs), especially SYP4, exhibit antifungal activity against several fungal species that are pathogenic for both humans and animals and are non-cytotoxic to animal red blood cells. In this study, we aimed to determine the effects of the bioactive peptides in SYPs against several pathogenic bacteria in humans and animals. After isolating SYP1, it was treated as follows: heated (SYP2), and hydrolyzed using pepsin (SYP3), and proteinase K (SYP4). Then, we used 500 μg of protein to evaluate the antibacterial effects on four pathogenic bacteria, including E. coli, P. aeruginosa, B. cereus, and S. aureus, using agar well diffusion. Using a broth microdilution assay, we determined the minimum inhibitory and bactericidal concentration (MIC and MBC, respectively) values of active SYPs. Using the agar well diffusion and microtube incubation methods, we also assessed the inhibitory effects of SYPs on the bacterial quorum sensing (QS) activity of Chromobacterium violaceum. Sangyod rice seed protein hydrolysates were evaluated for their ability to inhibit the biofilm formation of bacterial cells by a crytal violet assay. Furthermore, using the dropping method, we tested the inhibitory effects of SYPs on the bacterial pigments pyocyanin in P. aeruginosa and staphyloxanthin in S. aureus. Our results showed that the crude protein lysate (SYP1) did not exhibit antibacterial activity against any of the test bacteria. Intriguingly, after boiling (SYP2) and enzymatic hydrolysis (SYP3 and SYP4), the protein hydrolysates were transformed into bioactive peptides and displayed antibacterial properties against all of the test bacteria at a concentration of 500 μg as determined by agar well diffusion. SYP4 demonstrated the highest antibacterial activity as it completely inhibited all test strains, with inhibition zones ranging from 16.88 ± 0.25 to 21.25 ± 0.5 mm, and also yielded the highest MIC/MBC values against P. aeruginosa, B. cereus, and E. coli, at 256 and >256 μg/mL, respectively. We observed that at least 256 μg/mL of SYP4 is required to exhibit optimal antibacterial activity. At 16-128 μg/mL, it exhibited antibiofilm activity against S. aureus. Furthermore, at 256 μg/mL, SYP4 inhibited pyocyanin in P. aeruginosa and staphyloxanthin in S. aureus. Although SYP2 and SYP3 displayed weak antibacterial activity and their MIC values could not be obtained for all bacteria, they showed strong QS inhibition in C. violaceum at 256 μg protein. Moreover, SYP2 and SYP3, at a minimum concentration of 32 μg/mL, significantly reduced violacein production. SYP3 also showed biofilm reduction activity on S. aureus at least 16-512 μg/mL. Sangyod Phatthalung protein hydrolysates exerted excellent inhibitory effects against the growth of bacteria and their virulence factors, such as QS, biofilm formation, and/or pigment production. These factors include zoonotic and foodborne pathogens. Therefore, daily consumption of Sangyod Phatthalung rice might reduce the risk of bacterial pathogenesis and foodborne diseases. In conclusion, functional foods or alternate methods of treating bacterial illnesses may be developed in humans and animals.

Synthesis of Silver Nanoparticles from Aeromonas caviae for Antibacterial Activity and In Vivo Effects in Rats.

Silver nanoparticles (AgNPs) have excellent antimicrobial properties, as they can inhibit multidrug-resistant (MDR) pathogens. Furthermore, bio-AgNPs have potential applications in medicine due to their low toxicity and high stability. Here, AgNPs were synthesized from the biomass of Aeromonas caviae isolated from a sediment sample and subsequently characterized. The UV-Vis spectra of AgNPs in aqueous medium peaked at 417 nm, matching their plasmon absorption. The X-ray diffraction analysis (XRD) pattern of AgNPs showed four peaks at 2θ values, corresponding to Ag diffraction faces. Absorption band peaks at 3420.16, 1635.54, and 1399.43 cm-1 were identified by Fourier-transform infrared spectroscopy (FTIR) analysis as belonging to functional groups of AgNP-associated biomolecules. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed that the nanoparticles are spherical and pseudospherical, with sizes of 15-25 nm. Agar well diffusion minimal inhibitory concentration (MIC) assays were used to assess the antibacterial activity of the nanoparticles against MDR pathogens. AgNPs exhibited antibacterial activity against MDR bacteria. Two groups of albino rats received intraperitoneal injections of AgNPs at 15 mg/kg or 30 mg/kg for 7 days. Blood, kidney, and liver samples were collected to investigate hematological, biochemical, and histopathological alterations. Administered AgNPs in rats fluctuated in liver and kidney function parameters. The ultrastructural impacts of AgNPs were more prominent at higher doses. The results proved the easy, fast, and efficient synthesis of AgNPs using A. caviae isolates and demonstrated the remarkable potential of these AgNPs as antibacterial agents. Nanotoxicological studies are required to identify the specific dose that balances optimal antibacterial activity with minimal toxicity to human health.

Processing and biomedical applications of novel eco-sustainable fluconazole–loaded zinc oxide (ZnO) encapsulated chitosan (CS) biopolymer nanocomposite by inhibiting microbe species against candidiasis

Drug resistance and a lack of effective antifungal treatments have spurred the research and development of novel therapeutics to combat the fungus Candida albicans. Candida is ubiquitous yeast that is often colonized on the skin and mucosal membranes and is implicated in opportunistic fungal disorders all over the globe. In particular, nanoparticles (NPs) made of metals and metal oxides are a novel kind of functional nanohybrids with fascinating physio-chemical characteristics that have potential uses in nanoscience and medicine. In this current novel research attempt, a decisive biocompatible nanocomposite material with conflation of organic and inorganic sources has been successfully developed using a bis-triazole antifungal agent, fluconazol (FCZ)-assimilated zinc oxide (ZnO) as filler, and chitosan (CS) as matrix by a solution-based chemical method for potent biomedical applications. The eco-sustainable biomaterial ZnO NPs has been synthesized with a simple in situ precipitation method, in which the potent antifungal drug FCZ was implemented into the system to improve its strength, and the system was further modified by employing CS biopolymer. CS is an amorphous, translucent organic biopolymer with a structure unit similar to the polysaccharide structure of the extracellular matrix. This may provide mechanical strength to the nanocomposite by creating interfacial bonding between them. Such a novel nanocomposite has been physicochemically characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Ultra violet (UV), Scanning electron microscope (SEM), and particle size distribution (PSD). Additionally, the well diffusion technique was used to evaluate the ZnO-NPs and to develop FCZ-ZnO-CS nanocomposite for antibacterial and antifungal activities against Escherichia coli, Staphylococcus aureus, Candida albicans, and A. niger. The FCZ-ZnO-CS functionalized nanocomposite has excellent antifungal activity against Candida albicans and Aspergillus niger and optimum antibacterial activity against Escherichia coli and Staphylococcus aureus. Cytotoxicity studies demonstrated that the developed nanocomposite material FCZ-ZnO-CS has significant cytotoxicity against the mouse embryonic fibroblast (NIH-3T3) cell line. These results reveal that ZnO-incorporated fluconazole-chitosan (FCZ-ZnO-CS) could be used as an ideal material for candidiasis applications.

A novel formulation of triethyl orthoformate mediated durable, smart and antibacterial chitosan cross-linked cellulose fabrics

Antibacterial, durable and smart cotton fabrics was developed using chitosan-based formulation. The cellulose was covalently cross-linked with chitosan using TEOF. The antibacterial activity of prepared smart fabrics and CS was studied against S. aureus and E. coli strains. The FTIR, SEM and XRD were employed to confirm the linkage of CS molecules with cellulose in cotton fabrics. The CS of 160 KDa extracted from shrimp shell showed the optimum antibacterial activity. The prominent asymmetric, symmetric alkyl CH peaks of CS were shifted to 2930 and 2845 (cm−1), respectively. Moreover, the shifted peaks at 1590 and 1400 (cm−1) indicate the CO stretching and NH2 bending bands of CS, respectively. This confirm the existence of new imine functional group that was generated after cross-linking of NH2 groups of CS. The SEM results showed more uniform morphology of TEOF cross-linked fabrics versus CS coated fabrics, which revealed a promising microbial growth inhibition activity. The TEOF as a cross-linker has been unveiled, showcasing the effectiveness of this innovative crosslinking approach. The fabric treated with cross-linked CS exhibited remarkable antibacterial properties that endured even after undergoing 30 washing cycles. These antibacterial textiles possess substantial commercial potential across a diverse range of industries.

Investigation of the antimicrobial, antioxidant, hemolytic, and thrombolytic activities of Camellia sinensis, Thymus vulgaris, and Zanthoxylum armatum ethanolic and methanolic extracts.

Camellia sinensis is rich in antioxidants such as polyphenols; Thymus vulgaris contains bioactive compounds (flavonoids, terpenoids, and tannins) and Zanthoxylum armatum is primarily composed of volatile oils, amides, alkaloids, flavonoids, lignan, and coumarin. The antibacterial, antifungal, biofilm inhibition, antioxidant, hemolytic, and thrombolytic activities of Camellia sinensis, Thymus vulgaris, and Zanthoxylum armatum ethanol and methanol extracts at different concentrations (30%, 50%, and 80%) were determined. The antioxidant activity and content were measured as free radical scavenging assay (DPPH), total flavonoid content (TFC), and total phenolic content (TPC). Furthermore, hemolytic and thrombolytic analysis was carried out to determine toxicity. In antimicrobial assays, 80% methanol thyme extract showed highest (15.31 mm) antibacterial activity against Bacillus subtilis, and 80% ethanol green tea extract showed optimal antibacterial activity against Staphylococcus aureus. Ethanol 30% green tea extract resulted in highest (26.61 mm) antifungal activity against Aspergillus niger. The maximum (54.73%) biofilm inhibition was resulted by methanol 50% thyme extract for Escherichia coli. In antioxidant activity and content, methanol 50% green tea extract had highest (80.82%) antioxidant activity, whereas, ethanol 80% green tea extract had maximum (1474.55 mg CE/g DW) TFC and methanol 80% green tea extract had maximum (593.05 mg GAE/g) TPC. In toxicological assays, methanol 30% green tea extract had highest (25.28%) thrombolytic activity, and ethanol 80% tejphal extract had maximum (18.24%) hemolytic activity. This study has highlighted the significant antimicrobial, antioxidant, hemolytic, and thrombolytic activities of Camellia sinensis, Thymus vulgaris, and Zanthoxylum armatum extracts that could be beneficial to treat various diseases (cancer, diabetes, and respiratory diseases) and may be utilized as functional ingredient in the preparation of functional foods and drinks.

OPTIMALISASI AKTIVITAS ANTIBAKTERI EKSTRAK ETANOL 70% DAUN BINAHONG TERHADAP BAKTERI Staphylococcus aureus

Binahong leaf (Anredera cordifolia (Ten.) Steenis) contains flavonoids, alkaloids, tannins and saponins that function as antibacterial. Although antibacterial activity test of binahong leaves was done before, but not yet obtained optimum results using ethanol 70% as an extraction solvent. This study aims to determine the optimum antibacterial activity and the effect of increasing the concentration of 70% ethanolic extract of binahong leaves on Staphylococcus aureus bacteria. Binahong leaves were extracted by maceration method using ethanol 70% as solvent. The antibacterial activity was measured using the disc diffusion method and the inhibition zone obtained was also analyzed using statistical analysis. The results showed that the extract had good extract characteristics and contained a class of flavonoids, alkaloids, saponins, and tannins. The antibacterial activity of the binahong leaf extract showed a significant p-velue <0.05 from the Kruskal Wallis test with an inhibition zone in the moderate to strong group. Based on the results of this study it was concluded that the extract had good extract characteristics and contained several classes of phytochemical compounds. For antibacterial activity, the optimum concentration of antibacterial activity of 70% ethanolic extract of binahong leaves was obtained at an extract concentration of 80% with an inhibition zone was 12.85 mm and it also performed that the higher the concentration of the extract, the higher the antibacterial activity obtained.
 Keywords: Phytochemical Screening, Antibacterial Activity, Staphylococcus Aureus, Anredera cordifolia (Ten.) Steenis.

Construction of S-Scheme CuS/Bi5O7I Heterojunction for Boosted Photocatalytic Disinfection with Visible Light Exposure.

In this paper, a novel S-scheme CuS/Bi5O7I heterojunction was successfully constructed using a two-step approach comprising the alkaline hydrothermal method and the adsorption-deposition method, and it consisted of Bi5O7I microrods with CuS particles covering the surface. The photocatalytic antibacterial effects on Escherichia coli (E. coli) were systematically examined with visible light exposure. The results suggested that the 3%-CuS/Bi5O7I composite showed the optimal antibacterial activity, completely inactivating E. coli (5 × 108 cfu/mL) in 180 min of irradiation. Moreover, the bacterial inactivation process was scientifically described. •O2- and h+ were the major active species for the inactivation of the bacteria. In the early stages, SOD and CAT initiated the protection system to avoid the oxidative destruction of the active species. Unfortunately, the antioxidant protection system was overwhelmed thereafter, which led to the destruction of the cell membrane, as evidenced by the microstructure changes in E. coli cells. Subsequently, the leakage of intracellular components including K+, proteins, and DNA resulted in the unavoidable death of E. coli. Due to the construction of the S-scheme heterojunction, the CuS/Bi5O7I composite displayed the boosted visible light harvesting, the high-efficiency separation of photogenerated electrons and holes, and a great redox capacity, contributing to an outstanding photocatalytic disinfection performance. This work offers a new opportunity for S-scheme Bi5O7I-based heterojunctions with potential application in water disinfection.

Caffeine and Cationic Copolymers with Antimicrobial Properties.

One of the primary global health concerns is the increase in antimicrobial resistance. Polymer chemistry enables the preparation of macromolecules with hydrophobic and cationic side chains that kill bacteria by destabilizing their membranes. In the current study, macromolecules are prepared by radical copolymerization of caffeine methacrylate as the hydrophobic monomer and cationic- or zwitterionic-methacrylate monomers. The synthesized copolymers bearing tert-butyl-protected carboxybetaine as cationic side chains showed antibacterial activity toward Gram-positive bacteria (S. aureus) and Gram-negative bacteria (E. coli). By tuning the hydrophobic content, we prepared copolymers with optimal antibacterial activity against S. aureus, including methicillin-resistant clinical isolates. Moreover, the caffeine-cationic copolymers presented good biocompatibility in a mouse embryonic fibroblast cell line, NIH 3T3, and hemocompatibility with erythrocytes even at high hydrophobic monomer content (30-50%). Therefore, incorporating caffeine and introducing tert-butyl-protected carboxybetaine as a quaternary cation in polymers could be a novel strategy to combat bacteria.

Dual-Cascade Responsive Nanoparticles Enhance Pancreatic Cancer Therapy by Eliminating Tumor-Resident Intracellular Bacteria.

The limited drug penetration and robust bacteria-mediated drug inactivation in pancreatic cancer result in the failure of chemotherapy. To fight against these issues, a dual-cascade responsive nanoparticle (sNP@G/IR) that can sequentially trigger deep penetration, killing of intratumor bacteria, and controlled release of chemo-drug, is reported. sNP@G/IR consists of a hyaluronic acid (HA) shell and glutathione (GSH)-responsive polymer-core (NP@G/IR), that encapsulates gemcitabine (Gem) and photothermal agent (IR1048). The polymer core, as an antibiotic alternative, is tailored to exert optimal antibacterial activity and selectivity. sNP@G/IR actively homes in on the tumor due to the CD44 targeting of the HA shell, which is subsequently degraded by the hyaluronidase in the extracellular matrix. The resultant NP@G/IR in decreased size and reversed charge facilitates deep tumor penetration. After cellular endocytosis, the exposed guanidine on NP@G/IR kills intracellular bacteria through disrupting cell membranes. Intracellular GSH further triggers the controlled release of thecargo. Thus, the protected Gem eventually induces cell apoptosis. Under laser irradiation, the hyperthermia of IR1048 helps further elimination of tumors and bacteria. Moreover, sNP@G/IR activates immune response, thereby reinforcing anticancer capacity. Therefore, this dual-cascade responsive sNP@G/IR eliminates tumor-resident intracellular bacteria and augments drug delivery efficacy, providing a new avenue for improving cancer therapy.

Cellulose Nanofibers/Pectin/Pomegranate Extract Nanocomposite as Antibacterial and Antioxidant Films and Coating for Paper.

Bio-based polymer composites find increasing research and industrial interest in different areas of our life. In this study, cellulose nanofibers (CNFs) isolated from sugar beet pulp and nanoemulsion prepared from sugar beet pectin and pomegranate extract (PGE) were used for making films and used as coating with antioxidant and antimicrobial activities for paper. For Pectin/PGE nanoemulsion preparation, different ratios of PGE were mixed with pectin using ultrasonic treatment; the antibacterial properties were evaluated to choose the formula with the adequate antibacterial activity. The antioxidant activity of the nanoemulsion with the highest antimicrobial activity was also evaluated. The nanoemulsion with the optimum antibacterial activity was mixed with different ratios of CNFs. Mechanical, greaseproof, antioxidant activity, and antibacterial properties of the CNFs/Pectin/PGE films were evaluated. Finally, the CNFs/Pectin/PGE formulation with the highest antibacterial activity was tested as a coating material for paper. Mechanical, greaseproof, and air porosity properties, as well as water vapor permeability and migration of the coated layer from paper sheets in different media were evaluated. The results showed promising applicability of the CNFs/Pectin/PGE as films and coating material with antibacterial and antioxidant activities, as well as good stability for packaging aqueous, fatty, and acidic food products.

Synthesis and Antibacterial Activity Evaluation of Biphenyl and Dibenzofuran Derivatives as Potential Antimicrobial Agents against Antibiotic-Resistant Bacteria.

The escalating prevalence of antibiotic-resistant bacteria has led to a serious global public health problem; therefore, there is an urgent need for the development of structurally innovative antibacterial agents. In our study, a series of biphenyl and dibenzofuran derivatives were designed and synthesized by Suzuki-coupling and demethylation reactions in moderate to excellent yields (51–94% yield). Eleven compounds exhibited potent antibacterial activities against the prevalent antibiotic-resistant Gram-positive and Gram-negative pathogens, among which compounds 4′-(trifluoromethyl)-[1,1′-biphenyl]-3,4,5-triol (6i) and 5-(9H-carbazol-2-yl) benzene-1,2,3-triol (6m) showed the most potent inhibitory activities against methicillin-resistant Staphylococcus aureus and multidrug-resistant Enterococcus faecalis with MIC (minimum inhibitory concentration) values as low as 3.13 and 6.25 μg/mL, respectively. Compounds 3′,5′-dimethyl-[1,1′-biphenyl]-3,4,4′,5-tetraol (6e), 4′-fluoro-[1,1′-biphenyl]-3,4,5-triol (6g), and 4′-(trifluoromethyl)-[1,1′-biphenyl]-3,4,5-triol (6i) showed comparable inhibitory activities with ciprofloxacin to Gram-negative bacterium carbapenems-resistant Acinetobacter baumannii. Study of the structure–activity relationship indicated that a strong electron-withdrawing group on the A ring and hydroxyl groups on the B ring of biphenyls were beneficial to their antibacterial activities, and for benzo-heterocycles, N-heterocycle exhibited optimal antibacterial activity. These results can provide novel structures of antibacterial drugs chemically different from currently known antibiotics and broaden prospects for the development of effective antibiotics against antibiotic-resistant bacteria.

Antibacterial, Antiparasitic, and Cytotoxic Activities of Chemical Characterized Essential Oil of Chrysopogon zizanioides Roots.

This study aimed to investigate the chemical composition as well as the antibacterial, antiparasitic, and cytotoxic potentialities of the Brazilian Chrysopogon zizanioides root essential oil (CZ-EO) In addition, CZ-EO cytotoxicity to LLCMK2 adherent epithelial cells was assessed. The major compounds identified in CZ-EO were khusimol (30.0 ± 0.3%), β-eudesmol (10.8 ± 0.3%), α-muurolene (6.0 ± 0.1%), and patchouli alcohol (5.6 ± 0.2%). CZ-EO displayed optimal antibacterial activity against Prevotella nigrescens, Fusobacterium nucleatum, Prevotella melaninogenica, and Aggregatibacter actinomycetemcomitans, with Minimum Inhibitory Concentration (MIC) values between 22 and 62.5 µg/mL and Minimum Bactericidal Concentration (MBC) values between 22 and 400 µg/mL. CZ-EO was highly active against the L. amazonensis promastigote and amastigote forms (IC50 = 7.20 and 16.21 µg/mL, respectively) and the T. cruzi trypomastigote form (IC50 = 11.2 µg/mL). Moreover, CZ-EO showed moderate cytotoxicity to LLCMK2 cells, with CC50 = 565.4 µg/mL. These results revealed an interesting in vitro selectivity of CZ-EO toward the L. amazonensis promastigote and amastigote forms (Selectivity Index, SI = 78.5 and 34.8, respectively) and the T. cruzi trypomastigote form (SI = 50.5) compared to LLCMK2 cells. These results showed the promising potential of CZ-EO for developing new antimicrobial, antileishmanial, and antitrypanosomal drugs.

Ultrasonication induced nano-emulsification of thyme essential oil: Optimization and antibacterial mechanism against Escherichia coli

This study optimized the ultrasound emulsification process using response surface methodology (RSM) to obtain thyme essential oil nanoemulsions (TEON) with excellent dispersion characteristics and antibacterial activity. Based on the single-factor experiments, the effects of ultrasonic power (350–550 W), time (5–15 min) and emulsifier [Tween 80 (T80), sodium dodecyl sulfate (SDS), and cetylpyridinium chloride (CPC)] concentrations were determined on response variables, including droplet size, PDI, zeta-potential, MIC, and MBC. Further analysis of stability and antibacterial mechanism were also conducted based on the optimal results. TEON-T80, obtained at 527.45 W, 9.97 min, and 5.94 mg/mL with good stability, killed E. coli through extracellular release, whereas TEON-CPC obtained at 350 W, 14.44 min, and 0.15 mg/mL exhibited excellent antibacterial activity through electrostatic interaction. TEON-SDS obtained at 350 W, 15 min, and 1 mg/mL was poor in stability and antibacterial activity. All nanoemulsions destroyed cell morphology and caused severe cytoplasm leakage. Through a preliminary antibacterial mechanism study, we hypothesized a controlled in vitro release for TEON-T80, electrostatic interaction for TEON-CPC, and self-assembly together with cell penetration for TEON-SDS. Considering all the results, TEON-CPC was determined as the best nanoemulsion for optimal antibacterial activity. Also, optimizing the ultrasonication process is useful for preparing TEON with enhanced dispersion characteristics and antibacterial activity. • Optimizing ultrasonication induced thyme essential oil nanoemulsions (TEON). • Tween 80, SDS, and cetylpyridinium chloride (CPC) were selected as emulsifiers. • Optimized TEON with Tween 80 exhibited excellent storage stability. • Optimized TEON with CPC showed the strongest antibacterial activity on E. coli. • TEON-CPC showed bactericidal effect through strong electrostatic interaction.

Biocompatibility and antimicrobial activity of copper(II) oxide hybridized with nano silicate platelets

Nano-sized copper(II) oxide (CuO) is an interesting material with proficient antibacterial activities but limited due to its toxicity to mammalian cells. In this study, CuO nano-sized needles were coated on the surface of nano-silicate platelets (NSP), which were exfoliated from natural montmorillonite clays and with the thickness of about 1 nm, to form nanohybrids. Our findings indicate that NSPs can effectively prevent the aggregation of CuO needles, and significantly enhance antibacterial efficiency without affecting biocompatibility. An optimal antibacterial activity against Staphylococcus aureus exceeding 99% could be obtained, while that for Escherichia coli was about 88%. Electron paramagnetic resonance results suggest that •OH radicals, one of the reactive oxygen species generated by CuO/NSP, might damage the cellular components and thus result in the death of bacterial.

Finafloxacin, a Novel Fluoroquinolone, Reduces the Clinical Signs of Infection and Pathology in a Mouse Model of Q Fever.

Finafloxacin is a novel fluoroquinolone with optimal antibacterial activity in low pH environments, therefore offering a therapeutic advantage over some traditional antibiotics, in treating bacterial infections associated with acidic foci. Coxiella burnetii, the causative agent of Q fever, is a bacterium which resides and replicates in acidic intracellular parasitic vacuoles. The efficacy of finafloxacin was evaluated in vivo using the A/J mouse model of inhalational Q fever and was compared to doxycycline, the standard treatment for this infection and ciprofloxacin, a comparator fluoroquinolone. Finafloxacin reduced the severity of the clinical signs of infection and weight loss associated with Q fever, but did not reduce the level of bacterial colonization in tissues compared to doxycycline or ciprofloxacin. However, histopathological analysis suggested that treatment with finafloxacin reduced tissue damage associated with C. burnetii infection. In addition, we report for the first time, the use of viable counts on axenic media to evaluate antibiotic efficacy in vivo.

Biological activity of green synthesized silver nanoparticles and different plant extracts of Solanum khasianum Clarke

Solanum khasianum Clarke. (Solanaceae), an important medicinal plant used to treat several diseases. Leaf, root, fruit and bark extracts of S. khasianum and the green synthesized silver nanoparticles were assayed for its antibacterial activity against gram positive and gram negative bacteria, using agar well diffusion method. Among all the solvent extracts tested, methanolic extracts were found to possess elevated activity. The optimal antibacterial activity is exhibited by silver nanoparticles against Pseudomonas flourescens with a maximal zone of inhibition (22mm). In the present study, the efficacy of green synthesized silver nanoparticles over the different plant extracts of S. khasianum against different bacterial strains was reported. This investigation discloses the potentiality of using silver nanoparticles as an antibacterial agent.