Significant Bactericidal Activity Research Articles

Phytochemical analysis and antibacterial activity of Punica granatum L. seed extract against clinically isolated uropathogens

The discovery of plant based drugs and dietary supplements derived from plants has accelerated in recent years. Punica granatum L. is one such plant whose products are useful in the treatment of many diseases including urinary tract infections (UTI), since it is rich in various antioxidants like vitamin C, iron and phenolic compounds. Antioxidant rich fluids are known to prevent bacteria from adhering to the walls of the bladder and urethra; as a result UTI is cured or prevented. The present investigation aims to explore the urobactericidal activity of different solvent extracts of the seeds of P. granatum. In this study, P. granatum dried seed powder was extracted exhaustively with different solvents i.e. hexane, chloroform, acetone and methanol (HPG, CPG, APG and MPG). The presence of different phytochemicals in these extracts was assessed both qualitatively and quantitatively before evaluating their urobactericidal and uroprotective potency. It was found that seeds of pomegranate have many bioactive phytochemicals like terpenoids, steroids, tannins, coumarins, glycosides, flavonoids and phenolic compounds that contribute to its significant antibacterial activity and this was proved by various methods and the zone or degree of growth inhibition was measured against different uropathogens. It was observed that APG and MPG, which are rich in hydrophilic phytoconstituents have significant bactericidal activity in comparison to HPG and CPG, which are rich in hydrophobic compounds. Since, the active phytoconstituents present in P. granatum seed have potent urobactericidal activity, it can be further explored for its tremendous bioactive potentials and also attempts should be made to safeguard and cultivate this miraculous plant which would be beneficial to the society.

Poly (acetyl, arginyl) glucosamine disrupts Pseudomonas aeruginosa biofilms and enhances bacterial clearance in a rat lung infection model

Pseudomonas aeruginosa is a common opportunistic pathogen that can cause chronic infections in multiple disease states, including respiratory infections in patients with cystic fibrosis (CF) and non-CF bronchiectasis. Like many opportunists, P. aeruginosa forms multicellular biofilm communities that are widely thought to be an important determinant of bacterial persistence and resistance to antimicrobials and host immune effectors during chronic/recurrent infections. Poly (acetyl, arginyl) glucosamine (PAAG) is a glycopolymer that has antimicrobial activity against a broad range of bacterial species, and also has mucolytic activity, which can normalize the rheological properties of cystic fibrosis mucus. In this study, we sought to evaluate the effect of PAAG on P. aeruginosa bacteria within biofilms in vitro, and in the context of experimental pulmonary infection in a rodent infection model. PAAG treatment caused significant bactericidal activity against P. aeruginosa biofilms, and a reduction in the total biomass of preformed P. aeruginosa biofilms on abiotic surfaces, as well as on the surface of immortalized cystic fibrosis human bronchial epithelial cells. Studies of membrane integrity indicated that PAAG causes changes to P. aeruginosa cell morphology and dysregulates membrane polarity. PAAG treatment reduced infection and consequent tissue inflammation in experimental P. aeruginosa rat infections. Based on these findings we conclude that PAAG represents a novel means to combat P. aeruginosa infection, and may warrant further evaluation as a therapeutic.

Silver Carboxylate as an Antibiotic-Independent Antimicrobial: A Review of Current Formulations, in vitro Efficacy, and Clinical Relevance.

The increasing prevalence of multi-drug resistant pathogens has led to a renewed focus on the use of silver as an antibiotic-independent antimicrobial. Unfortunately, the use of many silver formulations may be limited by an uncontrolled release of silver with the potential for significant cytotoxic effects. Silver carboxylate (AgCar) has emerged as an alternative formulation of silver with the potential to mitigate these concerns while still displaying significant bactericidal activity. This article reviews the efficacy of silver carboxylate formulations as a promising novel antibiotic-independent antimicrobial. This study was conducted through a search of five electronic databases (PubMed, Embase, MEDLINE, Cochrane Library, and Web of Science) for relevant studies up to September 2022. Searches were conducted for types of "silver carboxylate" formulations. Sources were compiled based on title and abstract and screened for inclusion based on relevance and study design. A review of the antimicrobial activity and cytotoxicity of silver carboxylate was compiled based on this search. Current body of data suggests that silver carboxylate shows promise as an emerging antibiotic-independent antimicrobial, with significant bactericidal effects while minimizing cytotoxicity. Silver carboxylate addresses several of the limitations of more primitive formulations, including controlled dosing and fewer negative effects on eukaryotic cell lines. These factors are concentration-dependent and largely rely on the vehicle system used to deliver it. Although several silver carboxylate-based formulations like titanium dioxide/polydimethylsiloxane (TiO2/PDMS) matrix-eluting AgCar have shown promising results in vitro, and could potentially be utilized independently or in conjunction with current and future antimicrobial therapies, there is a need for further in vivo studies to validate their overall safety and efficacy profile.

Mycoplasma synoviae dihydrolipoamide dehydrogenase is an immunogenic fibronectin/plasminogen binding protein and a putative adhesin

Mycoplasma synoviae (M. synoviae) is an important avian pathogen that causes arthritis and airsacculitis in young chickens and turkeys. Infection by M. synoviae results in considerable economic losses to the poultry industry worldwide. Cytoadherence is a crucial stage during mycoplasma infection. Dihydrolipoamide dehydrogenase (PdhD) is a flavin-dependent enzyme that is critical for energy metabolism and redox balance. To date, its role in cytoadherence is poorly understood. In this study, recombinant PdhD from M. synoviae (rMSPdhD) was expressed in the supernatant component of E. coli BL21 and rabbit anti-rMSPdhD serum was prepared. rMSPdhD was shown to be an immunogenic protein by immunoblot assays, while the mycoplasmacidal assay revealed that the rabbit anti-rMSPdhD serum had a high complement-dependent mycoplasmacidal rate (88.5 %). Using a suspension immunofluorescence assay and subcellular localization analysis, MSPdhD was shown to be a surface-localized protein distributed in both the cytoplasm and cell membrane of M. synoviae. The enzymatic activity of rMSPdhD was determined by measuring its ability to reduce lipoamide to dihydrolipoamide and convert NADH to NAD+. Using an indirect immunofluorescence assay, rMSPdhD was shown to adhere to DF-1 chicken embryo fibroblast cells. Furthermore, the attachment of M. synoviae to DF-1 cells was significantly inhibited by rabbit anti-rMSPdhD serum. Western blot and ELISA binding assays confirmed that rMSPdhD also bound to fibronectin (Fn) and plasminogen (Plg) in a dose-dependent manner. In conclusion, our data show that MSPdhD is not only a biological enzyme, but also an immunogenic surface-exposed protein that can bind to Fn and Plg as well as adhere to host cells. In addition, we show that rabbit anti-rMSPdhD serum can inhibit the adhesion of M. synoviae to DF-1 cells and has a significant complement-dependent bactericidal activity. Our findings suggest that MSPdhD may be involved in the pathogenesis of M. synoviae.

Repurposing Sitafloxacin, Prulifloxacin, Tosufloxacin, and Sisomicin as Antimicrobials Against Biofilm and Persister Cells of Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a ubiquitous bacterium found in hospitals and the surrounding environment. The ability of P. aeruginosa to form biofilms confers high-level resistance to antibiotics, and the persister cells formed in the presence of high antibacterial drug concentrations make P. aeruginosa-related infections more refractory. Further, there rarely is an effective antimicrobial alternative when biofilm- and persister cell-targeting treatment fails. Using a high-throughput screening assay, we previously identified fluoroquinolones sitafloxacin, prulifloxacin, and tosufloxacin as well as aminoglycoside sisomicin among FDA-approved drugs with significant bactericidal activity against P. aeruginosa. In addition, in our current study, these antibiotics exhibited an effective time- and dose-dependent eradication effects against the preformed biofilms of P. aeruginosa at the concentrations of 2-4μM. These agents also exhibited bactericidal efficacy against CCCP-induced P. aeruginosa persister cells with the viable cell count decreased from 9.14 log10 CFU/mL to 6.15 (sitafloxacin), 7.59 (prulifloxacin), 4.27 (tosufloxacin), and 6.17 (sisomicin) log10 CFU/mL, respectively, following 4h of treatment. Furthermore, sisomicin was also effective against conventional antibiotics induced persister cells in a time-dependent manner within 24h. In addition, we confirmed the in vivo anti-biofilm efficacy of the identified antibiotics in a subcutaneous implantation biofilm-related infection model. Tosufloxacin exhibited the greatest in vivo bactericidal activity against P. aeruginosa biofilms with a reduction of 4.54 ΔLog10 CFU/mL compared to the vehicle group, followed by prulifloxacin, sitafloxacin, and sisomicin. Taken together, our results indicate that sitafloxacin, prulifloxacin, tosufloxacin, and sisomicin have great potential as alternatives for the treatment of refractory infections caused by P. aeruginosa biofilms and persister cells.

In vitro antibacterial activity of nimbolide against Helicobacter pylori

Ethnopharmacological relevanceNimbolide is one of hundreds of phytochemicals that have been identified within the neem tree (Azadirachta indica A. Juss). As an evergreen tree native to the Indian subcontinent, components of the neem tree have been used for millennia in traditional medicine to treat dental, gastrointestinal, urinary tract, and blood-related ailments, ulcers, headaches, heartburn, and diabetes. In modern times, natural oils and extracts from the neem tree have been found to have activities against a variety of microorganisms, including human pathogens.Aim of the study: Helicobacter pylori, a prevalent gastric pathogen, shows increasing levels of antibiotic resistance. Thus, there is an increasing demand for novel therapeutics to treat chronic infections. The in vitro activity of neem oil extract against H. pylori was previously characterized and found to be bactericidal. Given the numerous phytochemicals found in neem oil extract, the present study was designed to define and characterize specific compounds showing bactericidal activity against H. pylori. Materials and methodsAzadirachtin, gedunin, and nimbolide, which are all common in neem extracts, were tested for antimicrobial activity; the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined for nine strains of H. pylori. The specific properties of nimbolide were further characterized against H. pylori strain G27. Bactericidal kinetics, reversibility, effectiveness at low pH, and activity under bacteriostatic conditions were examined. The hemolytic activity of nimbolide was also measured. Finally, neem oil extract and nimbolide effectiveness against H. pylori biofilms were examined in comparison to common antibiotics used to treat H. pylori infection. ResultsNimbolide, but not azadirachtin or gedunin, was effective against H. pylori; MICs and MBCs against the nine tested strains ranged between 1.25–5 μg/mL and 2.5–10 μg/mL, respectively. Additionally, neem oil extract and nimbolide were both effective against H. pylori biofilms. Nimbolide exhibited no significant hemolytic activity at biologically relevant concentrations. The bactericidal activity of nimbolide was time- and dose-dependent, independent of active H. pylori growth, and synergistic with low pH. Furthermore, nimbolide-mediated H. pylori cell death was irreversible after exposure to high nimbolide concentrations (80 μg/mL, after 2 h of exposure time and 40 μg/mL after 8 h of exposure). ConclusionsNimbolide has significant bactericidal activity against H. pylori, killing both free living bacterial cells as well as cells within a biofilm. Furthermore, the lack of hemolytic activity, synergistic activity at low pH and bactericidal properties even against bacteria in a state of growth arrest are all ideal pharmacological and biologically relevant properties for a potential new agent. This study underscores the potential of neem oil extract or nimbolide to be used as a future treatment for H. pylori infection.

Synthesis of MgO nanoparticles for different annealing temperatures and its biomedical applications

In this paper, we report the synthesis of MgO nanoparticles (NPs) by the co-precipitation method. The structural properties of the samples were characterised by X-ray diffraction, which revealed that the MgO Nps have a cubic structure. The functional groups of the as-synthesised samples were analysed by Fourier transform infrared spectroscopy. The optical properties of the as-synthesised samples were studied by UV-vis spectroscopy in the range of 200–800 nm, and the energy bandgap was calculated by the taus relation. The magnesium oxide (MgO) nanoparticles (NPs) showed significant dose-dependent bactericidal activity in both gram-negative and gram-positive bacteria. From the analysis of the antibacterial and antifungal activities of MgO NPs, it is revealed that the dose is sufficient for killing. These may be used in medical applications.

Photo-Enhanced Antimicrobial Activity of Polymers Containing an Embedded Photosensitiser.

This work presents the synthesis of a novel photosensitive acrylate monomer for use as both a self-catalyst in the photoinduced electron/energy transfer-reversible addition fragmentation chain transfer (PET-RAFT) polymerisation process and a photosensitiser (PS) for antibacterial applications. Hydrophilic, cationic, and antimicrobial formulations are explored to compare the antibacterial effects between charged and non-charged polymers. Covalent attachment of the catalyst to well-defined linear polymer chains has no effect on polymerisation control or singlet oxygen generation. The addition of the PS to polymers provides activity against S. aureus for all polymer formulations, resulting in up to a 99.99999 % killing efficacy in 30 min. Antimicrobial peptide mimetic polymers previously active against P. aeruginosa, but not S. aureus, gain significant bactericidal activity against S. aureus through the inclusion of PS groups, with 99.998 % killing efficiency after 30 min incubation with light. Thus, a broader spectrum of antimicrobial activity is achieved using two distinct mechanisms of bactericidal activity via the incorporation of a photosensitiser monomer into an antimicrobial polymer.

Photo‐Enhanced Antimicrobial Activity of Polymers Containing an Embedded Photosensitiser

AbstractThis work presents the synthesis of a novel photosensitive acrylate monomer for use as both a self‐catalyst in the photoinduced electron/energy transfer–reversible addition fragmentation chain transfer (PET‐RAFT) polymerisation process and a photosensitiser (PS) for antibacterial applications. Hydrophilic, cationic, and antimicrobial formulations are explored to compare the antibacterial effects between charged and non‐charged polymers. Covalent attachment of the catalyst to well‐defined linear polymer chains has no effect on polymerisation control or singlet oxygen generation. The addition of the PS to polymers provides activity against S. aureus for all polymer formulations, resulting in up to a 99.99999 % killing efficacy in 30 min. Antimicrobial peptide mimetic polymers previously active against P. aeruginosa, but not S. aureus, gain significant bactericidal activity against S. aureus through the inclusion of PS groups, with 99.998 % killing efficiency after 30 min incubation with light. Thus, a broader spectrum of antimicrobial activity is achieved using two distinct mechanisms of bactericidal activity via the incorporation of a photosensitiser monomer into an antimicrobial polymer.

Recombinant Antimicrobial Peptide Fusion Between Crotalicidin Fragment Tag and Bacteriophage Endolysin T5 as a Potential Antibacterial Agent Against Multidrug Resistant Gram-Negative Bacteria: A Research Protocol

Introduction: Endolysins, antimicrobial peptides that disrupt the peptidoglycan (PG) layer of bacteria, are a strong alternative to common antibiotics and less prone to antibiotic resistance. However, endolysins are ineffective against gram-negative bacteria due to an additional outer membrane (OM) blocking the PG layer. This research protocol aims to address this caveat by developing a novel recombinant endolysin peptide, EndoT5-Ctn (15-34), comprised of phage Endolysin T5 and a Crotalicidin tag (Ctn (15-34)) capable of permeabilizing the OM. This would render the endolysin effective against gram-negative bacteria such as multidrug-resistant (MDR) Pseudomonas aeruginosa. Methods: Experimentation will begin with recombinant DNA techniques to engineer a bacterial vector which expresses the EndoT5-Ctn (15-34) peptide. Protein expression will be achieved in competent BL21 (DE3) E. coli strains before protein isolation with lysis methods and immobilized-metal affinity chromatography. Resulting sample concentrations will be assayed using spectrophotometry. Finally, in vivo minimal inhibitory and bactericidal concentration assays will be conducted on MDR P. aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) to evaluate bactericidal efficacy. Results: A minimal bactericidal concentration of EndoT5-Ctn (15-34) recombinant endolysin is expected to yield significant bactericidal activity against the MDR P. aeruginosa strain with limited effect on the gram-positive MRSA. A higher concentration of recombinant endolysin is expected to maintain its gram-negative bactericidal efficacy with an imported gram-positive bactericidal efficacy. Discussion: The observed bactericidal efficacy on AMR and non-AMR strains on P. aeruginosa will prompt further exploration of the therapeutic feasibility of this therapy regarding factors such as cytotoxicity, immunogenicity, and thermal stability. The potential introduction of recombinant endolysins presents an alternative treatment for infections with reduced risk of inducing resistant mutations. Conclusion: The EndoT5-Ctn (15-34) recombinant endolysin is a novel anti-bacterial agent which is expected to have significant bactericidal effects on MDR strains of gram-negative bacteria which current antibiotics have been ineffective at combating.

Photocatalytic TiO2/CdS/ZnS nanocomposite induces Bacillus subtilis cell death by disrupting its metabolism and membrane integrity.

The online version contains supplementary material available at 10.1007/s12088-021-00973-z.

Neutrophil Myeloperoxidase Derived Chlorolipid Production During Bacteria Exposure.

Neutrophils are the most abundant white blood cells recruited to the sites of infection and inflammation. During neutrophil activation, myeloperoxidase (MPO) is released and converts hydrogen peroxide to hypochlorous acid (HOCl). HOCl reacts with plasmalogen phospholipids to liberate 2-chlorofatty aldehyde (2-ClFALD), which is metabolized to 2-chlorofatty acid (2-ClFA). 2-ClFA and 2-ClFALD are linked with inflammatory diseases and induce endothelial dysfunction, neutrophil extracellular trap formation (NETosis) and neutrophil chemotaxis. Here we examine the neutrophil-derived chlorolipid production in the presence of pathogenic E. coli strain CFT073 and non-pathogenic E. coli strain JM109. Neutrophils cocultured with CFT073 E. coli strain and JM109 E. coli strain resulted in 2-ClFALD production. 2-ClFA was elevated only in CFT073 coculture. NETosis is more prevalent in CFT073 cocultures with neutrophils compared to JM109 cocultures. 2-ClFA and 2-ClFALD were both shown to have significant bactericidal activity, which is more severe in JM109 E. coli. 2-ClFALD metabolic capacity was 1000-fold greater in neutrophils compared to either strain of E. coli. MPO inhibition reduced chlorolipid production as well as bacterial killing capacity. These findings indicate the chlorolipid profile is different in response to these two different strains of E. coli bacteria.

Screening of Compounds for Anti-tuberculosis Activity, and in vitro and in vivo Evaluation of Potential Candidates.

Tuberculosis (TB) is a debilitating infectious disease responsible for more than one million deaths per year. The emergence of drug-resistant TB poses an urgent need for the development of new anti-TB drugs. In this study, we screened a library of over 4,000 small molecules and found that orbifloxacin and the peptide AK15 possess significant bactericidal activity against Mycobacterium tuberculosis (Mtb) in vitro. Orbifloxacin also showed an effective ability on the clearance of intracellular Mtb and protect mice from a strong inflammatory response but not AK15. Moreover, we identified 17 nucleotide mutations responsible for orbifloxacin resistance by whole-genome sequencing. A critical point mutation (D94G) of the DNA gyrase (gyrA) gene was found to be the key role of resistance to orbifloxacin. The computational docking revealed that GyrA D94G point mutation can disrupt the orbifloxacin–protein gyrase interactions mediated by magnesium ion bridge. Overall, this study indicated the potential ability of orbifloxacin as an anti-tuberculosis drug, which can be used either alone or in combination with first-line antibiotics to achieve more effective therapy on TB.

Senna mediated facile green synthesis of nano ceria and its photo-catalytic and biological application

Multifunctional and bioactive cerium oxide nanoparticles (CeO2 Nps) were successfully synthesized by Solution Combustion Synthesis (SCS). Aqueous extract of Cassia angustifolia (Senna) was used as reducing agent for the green synthesis of Nps. The obtained Nps were characterized by powder X-Ray diffraction, Scanning Electron Microscopy (SEM) and UV–visible spectroscopic studies. XRD diffractions revealed the formation of pure cubic ceria phase with fluorite structure having crystallite sizes in the range of 10–50 nm. SEM studies indicate the formation of porous nanostructured materials. UV–visible spectrum exhibited characteristic absorption maximum at 318 nm. The Nps were subjected for evaluating the photo-catalytic degradation efficiency of carcinogenic dyes Methylene blue (MB) and Malachite green (MG). Comprehensive degradation of the MB and MG was observed in a span of 180 min and 160 min, respectively. The antioxidant activity of Npswas evaluated through the scavenging of 1,1-Diphenyl-2-picrylhydrazyl (DPPH) free radical. The Nps showed good antioxidant activity with IC50 value of 3142 µg/ml. Nps exhibited significant bactericidal activities on Klebsiellaaerogenes, Escherichia coli, Pseudomonas desmolyticum and Staphylococcus aureus. The antidiabetic potential of CeO2-Nps was assessed and they exhibited excellent α-glucosidase (IC50 at 111.33 µg/ml) and α- amylase (IC 50 at 89.96 µg/ml) activity. The cytotoxic effects of CeO2Nps were studied against MCF 7 (human breast cancer) cell line by MTT assay which showed dose dependent response. IC50 values were found to be 249 µg/ml demonstrating their higher cytotoxic efficacy. The study demonstrates a simple, economical and environment friendly method of Solution Combustion Synthesis that results in the preparation of multifunctional CeO2 Nps. The green synthesis of cerium oxide Nps employing aqueous extract of Cassia angustifolia is suggested as effective and substitute method for the hazardous chemical synthesis.

Dye degradation, antibacterial and in-silico analysis of Mg/cellulose-doped ZnO nanoparticles

Various concentrations of Mg into fixed amount of cellulose nanocrystals (CNC)-doped ZnO were synthesized using facile chemical precipitation. The aim of present study is to remove dye degradation of methylene blue (MB) and bactericidal behavior with synthesized product. Phase constitution, functional group analysis, optical behavior, elemental composition, morphology and microstructure were examined using XRD, FTIR, UV–Vis spectrophotometer, EDS and HR-TEM. Highly efficient photocatalytic performance was observed in basic medium (98%) relative to neutral (65%), and acidic (83%) was observed upon Mg and CNC co-doping. Significant bactericidal activity of doped ZnO nanoparticles depicted inhibition zones for G –ve and +ve bacteria ranging (2.20 - 4.25 mm) and (5.80–7.25 mm) for E. coli and (1.05 - 2.75 mm) and (2.80 - 4.75 mm) for S. aureus at low and high doses, respectively. Overall, doped nanostructures showed significant (P < 0.05) bactericidal efficacy against G +ve relative to G –ve. Furthermore, the molecular docking studies were employed to rationalize possible mechanism behind these in vitro bactericidal activities. In silico findings suggested CNC doped ZnO nanocomposites as possible inhibitors of β-lactamase (Binding score: −7.936 kcal/mol), DHFR (Binding score: −5.691 kcal/mol) and FabI (Binding score: −8.673 kcal/mol).

Hemi Labile Intramolecular N → Sn Coordination in a Diorganotin (IV) Sulfide [R2Sn(µ-S)]2 (R = 2-phenylazophenyl) Complex: Synthesis, Structure, DFT-NBO and Antibacterial Studies

The dinuclear diorganotin sulfide [R2Sn(µ-S)]2 (1) (R = 2-phenylazophenyl) was synthesized by the room temperature reaction of the N → Sn intramolecularly coordinated starting precursor R2SnCl2 and Na2S·9H2O in acetone/methanol (1:1). The molecular structure of 1 was primarily characterized by single crystal X-ray crystallography. Furthermore, 1 was also characterized by other experimental techniques, such as 1H, 13C and 119Sn NMR, ESI-MS, FTIR spectroscopy. Complex 1 crystallized in the monoclinic P21/n space group. Each tin center of complex 1 is pentacoordinated and acquires a distorted trigonal bipyramidal geometry. Time dependent density functional theory (TD-DFT) analysis revealed that the transitions observed in complex 1 are predominantly of the ligand-to-ligand type. Natural bond orbital (NBO) analysis showed that complex 1 consists of three ionic bonds (2Sn-C and Sn-S) and two ligand to metal coordinate bonds (S → Sn and N → Sn). HOMO-LUMO analysis suggested that the HOMO of complex 1 is mainly sulfur based. The complex 1 showed significant bactericidal activity against both gram positive and negative bacteria.

Evaluation of a novel bioactive wound dressing: an in vitro and in vivo study.

Hard-to-heal wounds, such as pressure ulcers and diabetic ulcers, are a major challenge for wound dressings. The aim of this study was to develop a bioactive dressing based on polymers and natural materials with unique biological and therapeutic properties. The dressing was composed of an active layer containing polyvinyl alcohol (PVA), honey, curcumin and keratin, and an upper layer with lower hydrophilicity comprising PVA to induce flexibility. Physicochemical properties of the dressing were characterised by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, swelling behaviour and antibacterial measurements. A wound healing study was performed using an experimental rat model and two different compositions of the bioactive dressing were compared with a commercial wound dressing (Comfeel, Coloplast, Denmark). Histopathological evaluation was conducted for this purpose. Characterisation results showed that a smooth bilayer film with two homogenous but distinct layers was produced. The dressing also provided adequate moisture to the wound environment without infection and adhesion due to dryness occurring. Our results exhibited significant bactericidal activity against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria and improved the wound healing process without any scarring. Histopathological findings demonstrated a significant higher healing rate in vivo together with well-formed epidermis, granulation tissue formation and tissue contraction, when compared with the commercial wound dressing. Our results demonstrated acceptable physical and healing effects for the novel bioactive wound dressing; however, more investigations are recommended.

Discovery of Novel Thiophene-arylamide Derivatives as DprE1 Inhibitors with Potent Antimycobacterial Activities.

In this study, we report the design and synthesis of a series of novel thiophene-arylamide compounds derived from the noncovalent decaprenylphosphoryl-β-d-ribose 2′-epimerase (DprE1) inhibitor TCA1 through a structure-based scaffold hopping strategy. Systematic optimization of the two side chains flanking the thiophene core led to new lead compounds bearing a thiophene-arylamide scaffold with potent antimycobacterial activity and low cytotoxicity. Compounds 23j, 24f, 25a, and 25b exhibited potent in vitro activity against both drug-susceptible (minimum inhibitory concentration (MIC) = 0.02–0.12 μg/mL) and drug-resistant (MIC = 0.031–0.24 μg/mL) tuberculosis strains while retaining potent DprE1 inhibition (half maximal inhibitory concentration (IC50) = 0.2–0.9 μg/mL) and good intracellular antimycobacterial activity. In addition, these compounds showed good hepatocyte stability and low inhibition of the human ether-à-go-go related gene (hERG) channel. The representative compound 25a with acceptable pharmacokinetic property demonstrated significant bactericidal activity in an acute mouse model of tuberculosis. Moreover, the molecular docking study of template compound 23j provides new insight into the discovery of novel antitubercular agents targeting DprE1.

Natural clay loaded Sm2MoO6 nanocomposite, a green catalyst, for multiple applications

In the present work, multiple applications of natural clay loaded Samarium molybdate for photodegradation, sensing and antibacterial activity were analyzed. The clay-based materials have attracted great attention as they show good application prospects for environmental remediation. We developed natural clay loaded Sm2MoO6 (CSm2MoO6) nanocomposite, hydrothermally and characterized by XRD, SEM, HR-TEM, FT-IR and optical studies. XRD pattern of CSm2MoO6 exhibits peaks at 19.60, 27.80, 35.60 and 62.40 corresponding to clay and Sm2MoO6 peaks clearly indicates the formation of natural clay conjugated with Sm2MoO6. SEM image of the natural clay doped CSm2MoO6 nanoparticle shows a homogeneous distribution of spherical Sm2MoO6on nanoflakes of clay material. HR-TEM images reveal that the average particle size is 50 nm. Loading of natural clay material increased the visible absorption of Sm2MoO6 by reducing the band gap from 3.82 to 2.39 eV. Decomposition of 20 ppm of Metronidazole (MNZ) was 95% with 60 mg of CSm2MoO6 in 100 min of visible light illumination. Hydroxyl radicals played the main role for photodegradation of MNZ. Electrochemical analysis revealed that the oxidation peak current of 4-aminophenol has increased with a high potential at pH 6.0 and CSm2MoO6/SPCE electrode has an advantage of low detection limit of 0.005 μM and a long linear range of 2949.72 μM with a sensitivity of 5.29301 μM. The synthesized nanocomposite has a significant bactericidal activity against Bacillus subtilis, Staphylococcus aureus, Proteus mirabilis, Bacteroides fragilis, E. coli and Candida albicans. These results make this green catalyst potential for multiple applications.

Antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite against pathogenic bacteria and parasite.

Conducting polymer based nanocomposites are known to be effective against pathogens. Herein,we report the antimicrobial properties of multifunctional polypyrrole-cobalt oxide-silver nanocomposite (PPy-Co3O4-AgNPs) for the first time. Antibacterial activities were tested against multi-drug-resistant Gram-negative Escherichia coli (E. coli) and Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) bacteria, while antiamoebic effects were assessed against opportunistic protist Acanthamoeba castellanii (A. castellanii). The ternary nanocomposite containing conducting polymer polypyrrole, cobalt oxide, and silver nanoparticles showed potent antimicrobial effects against these pathogens. The antibacterial assay showed that PPy-Co3O4-AgNPs exhibited significant bactericidal activity against neuropathogenic E. coli K1 at only 8 μg/mL as compared to individual components of the nanocomposite, whereas a 70 % inhibition of A. castellanii viability was observed at 50 μg/mL. Moreover, PPy-Co3O4-AgNPs were found to have minimal cytotoxicity against human keratinocytes HaCaT cells in vitro even at higher concentration (50 μg/mL), and also reduced the microbes-mediated cytopathogenicity against host cells. These results demonstrate that PPy-Co3O4-AgNPs hold promise in the development of novel antimicrobial nanomaterials for biomedical applications. •Synthesis of polypyrrole-cobalt oxide-silver (PPy-Co3O4-AgNPs) nanocomposite. •Antimicrobial activity of nanocomposite. •PPy-Co3O4-AgNPs hold promise for biomedical applications.