scholarly journals Robust Antibacterial Activity of Tungsten Oxide (WO3-X) Nanodots

2018 ◽  
Author(s):  
Guangxin Duan ◽  
Lu Chen ◽  
Zhifeng Jing ◽  
Phil De Luna ◽  
Lin Wen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antibacterial Activity ◽  
Tungsten Oxide ◽  
Bacterial Infections ◽  
Antibacterial Agents ◽  
Inorganic Materials ◽  
Cell Counting ◽  
Resonance Spectroscopy ◽  
Synthetic Approach ◽  
E Coli

AbstractAntibacterial agents are an important tool in the prevention of bacterial infections. Inorganic materials are attractive due to their high stability under a variety of conditions compared to organic antibacterial agents. Herein tungsten oxide nanodots (WO3-X), synthesized by a simple one-pot synthetic approach, was found to exhibit efficient antibacterial capabilities. The analyses with colony-forming units (CFU) showed excellent antibacterial activity of WO3-X against both gram-negative E. coli (Escherichia coli) and gram-positive S. aureus (Staphylococcus aureus) strains. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images revealed clear damage to the bacterial cell membranes, which was further confirmed by molecular dynamics simulations. Additionally, exposure to simulated sunlight was found to further increase germicidal activity of WO3-X nanodots – a 30-minute exposure to sunlight (combining 50 μg/mL WO3-X nanodots) showed a 70% decrease in E. coli viability compared to without exposure. Electron spin resonance spectroscopy (ESR) was used to elucidate the underlying mechanism of this photocatalytic activity through the generation of hydroxyl radical species. Cell counting kit-8 (CCK-8) and the live/dead assay were further employed to evaluate the cytotoxicity of WO3-X nanodots on eukaryotic cells, which demonstrated their general biocompatibility. In all, our results suggest WO3-X nanodots have considerable potential in antibacterial applications, while also being biocompatible at large.

scholarly journals 1,4-Naphthoquinone Analogues: Potent Antibacterial Agents and Mode of Action Evaluation

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1437 ◽  
Author(s):  
Palanisamy Ravichandiran ◽  
Sunirmal Sheet ◽  
Dhanraj Premnath ◽  
Ae Rhan Kim ◽  
Dong Jin Yoo
Keyword(s):  
Antibacterial Activity ◽  
Mode Of Action ◽  
Bacterial Infections ◽  
Antibacterial Agents ◽  
Annexin V ◽  
Ros Generation ◽  
Redox Potentials ◽  
Bacterial Strains ◽  
E Coli ◽  
New Class

1,4-Naphthoquinones have antibacterial activity and are a promising new class of compound that can be used to treat bacterial infections. The goal was to improve effective antibacterial agents; therefore, we synthesized a new class of naphthoquinone hybrids, which contain phenylamino-phenylthio moieties as significant counterparts. Compound 4 was modified as a substituted aryl amide moiety, which enhanced the antibacterial activity of earlier compounds 3 and 4. In this study, five bacterial strains Staphylococcus aureus (S. aureus), Listeria monocytogenes (L. monocytogenes), Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Klebsiella pneumoniae (K. pneumoniae) were used to evaluate the antibacterial potency of synthesized naphthoquinones using the minimal inhibitory concentration (MIC) method. Most of the studied naphthoquinones demonstrated major antibacterial activity with a MIC of 15.6 µg/mL–500 µg/mL. Selected compounds (5a, 5f and 5x) were studied for the mode of action, using intracellular ROS generation, determination of apoptosis by the Annexin V-FITC/PI assay, a bactericidal kinetic study and in silico molecular modelling. Additionally, the redox potentials of the specified compounds were confirmed by cyclic voltammetry (CV).

Synthesis, Characterization and Antimicrobial Activity of 4-Substituted-Benzylpiperazinyl Methanone Derivatives

2017 ◽  
Vol 10 (2) ◽  
pp. 3684-3687
Author(s):  
Mahesh Chidara ◽  
Satla Shobha Rani
Keyword(s):  
Antibacterial Activity ◽  
Antifungal Activity ◽  
Bacterial Infections ◽  
Antibacterial Agents ◽  
Mass Spectral Data ◽  
Future Studies ◽  
Mass Spectral ◽  
E Coli ◽  
H Nmr ◽  
Good Antibacterial Activity

Novel antibacterial compounds are needed to combat the emerging bacterial infections. In this study, synthesis of 4-substituted benzylpiperazin-1-yl methanone derivatives was carried out by 4-substituted benzyl chloride (I) with piperazine in presence of ethanol to obtain 4-substituted benzylpiperazines (II). Benzylpiperazines (II) was condensed with different substituted esters in presence of diluted acid to produce title compounds (IIIa–e, IVa-e and Va-e). All the title compounds were screened for possible antibacterial activity against P. Vulgaris, S. Aureas, E. Coli, B. Subtillus and antifungal activity against Altenaria, Culvalaria, C. Albicans and A. Niger. Among the compounds synthesized IVb, IVd and IVf demonstrated good antibacterial activity; IVb, IVc, and IVe showed good antifungal activity. The activities of the synthesized compounds are compared with the standard and other test compounds. The structures of synthesized compounds were established by elemental analysis, IR, H NMR and Mass spectral data. Future studies will confirm their efficacy and utility as antibacterial agents. 

Large-scale High-throughput Screening Revealed 5'-(carbonylamino)-2,3'- bithiophene-4'-carboxylate as Novel Template for Antibacterial Agents

2020 ◽  
Vol 17 (5) ◽  
pp. 716-724
Author(s):  
Yan A. Ivanenkov ◽  
Renat S. Yamidanov ◽  
Ilya A. Osterman ◽  
Petr V. Sergiev ◽  
Vladimir A. Aladinskiy ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
High Throughput ◽  
High Throughput Screening ◽  
Large Scale ◽  
Antibacterial Agents ◽  
Sos Response ◽  
Luciferase Assay ◽  
Translational Machinery ◽  
E Coli ◽  
New Class

Background: The key issue in the development of novel antimicrobials is a rapid expansion of new bacterial strains resistant to current antibiotics. Indeed, World Health Organization has reported that bacteria commonly causing infections in hospitals and in the community, e.g. E. Coli, K. pneumoniae and S. aureus, have high resistance vs the last generations of cephalosporins, carbapenems and fluoroquinolones. During the past decades, only few successful efforts to develop and launch new antibacterial medications have been performed. This study aims to identify new class of antibacterial agents using novel high-throughput screening technique. Methods: We have designed library containing 125K compounds not similar in structure (Tanimoto coeff.< 0.7) to that published previously as antibiotics. The HTS platform based on double reporter system pDualrep2 was used to distinguish between molecules able to block translational machinery or induce SOS-response in a model E. coli system. MICs for most active chemicals in LB and M9 medium were determined using broth microdilution assay. Results: In an attempt to discover novel classes of antibacterials, we performed HTS of a large-scale small molecule library using our unique screening platform. This approach permitted us to quickly and robustly evaluate a lot of compounds as well as to determine the mechanism of action in the case of compounds being either translational machinery inhibitors or DNA-damaging agents/replication blockers. HTS has resulted in several new structural classes of molecules exhibiting an attractive antibacterial activity. Herein, we report as promising antibacterials. Two most active compounds from this series showed MIC value of 1.2 (5) and 1.8 μg/mL (6) and good selectivity index. Compound 6 caused RFP induction and low SOS response. In vitro luciferase assay has revealed that it is able to slightly inhibit protein biosynthesis. Compound 5 was tested on several archival strains and exhibited slight activity against gram-negative bacteria and outstanding activity against S. aureus. The key structural requirements for antibacterial potency were also explored. We found, that the unsubstituted carboxylic group is crucial for antibacterial activity as well as the presence of bulky hydrophobic substituents at phenyl fragment. Conclusion: The obtained results provide a solid background for further characterization of the 5'- (carbonylamino)-2,3'-bithiophene-4'-carboxylate derivatives discussed herein as new class of antibacterials and their optimization campaign.

Fluoroquinolone-3-carboxamide Amino Acid Conjugates: Synthesis, Antibacterial Properties And Molecular Modeling Studies

2020 ◽  
Vol 17 (1) ◽  
pp. 71-84
Author(s):  
Riham M. Bokhtia ◽  
Siva S. Panda ◽  
Adel S. Girgis ◽  
Hitesh H. Honkanadavar ◽  
Tarek S. Ibrahim ◽  
...  
Keyword(s):  
Experimental Data ◽  
Antibacterial Activity ◽  
Amino Acid ◽  
Bacterial Infections ◽  
Antibacterial Agents ◽  
Antibacterial Properties ◽  
Computational Studies ◽  
Protecting Group ◽  
Amino Acid Conjugates ◽  
Molecular Modeling Studies

Background: Bacterial infections are considered as one of the major global health threats, so it is very essential to design and develop new antibacterial agents to overcome the drawbacks of existing antibacterial agents. Method: The aim of this work is to synthesize a series of new fluoroquinolone-3-carboxamide amino acid conjugates by molecular hybridization. We utilized benzotriazole chemistry to synthesize the desired hybrid conjugates. Result: All the conjugates were synthesized in good yields, characterized, evaluated for their antibacterial activity. The compounds were screened for their antibacterial activity using methods adapted from the Clinical and Laboratory Standards Institute. Synthesized conjugates were tested for activity against medically relevant pathogens; Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27856) Staphylococcus aureus (ATCC 25923) and Enterococcus faecalis (ATCC 19433). Conclusion: The observed antibacterial experimental data indicates the selectivity of our synthesized conjugates against E.Coli. The protecting group on amino acids decreases the antibacterial activity. The synthesized conjugates are non-toxic to the normal cell lines. The experimental data were supported by computational studies.

scholarly journals Fabrication & Characterization of Chitosan Coated Biologically Synthesized TiO2 Nanoparticles against PDR E. coli of Veterinary Origin

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Naheed Zafar ◽  
Bushra Uzair ◽  
Muhammad Bilal Khan Niazi ◽  
Shamaila Sajjad ◽  
Ghufrana Samin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Antibacterial Activity ◽  
Titanium Dioxide ◽  
Morphological Changes ◽  
Titanium Dioxide Nanoparticles ◽  
Chitosan Nanoparticles ◽  
Diffusion Method ◽  
Potential Threat ◽  
E Coli

Treatment of pandrug resistant (PDR) Escherichia coli strain is the leading causative agent of bovine mastitis worldwide. Hence, becoming a potential threat to veterinary and public health. Therefore, to control the infection new nontoxic, biocompatible antimicrobial formulation with enhanced antibacterial activity is massively required. Current study was planned to synthesize chitosan coated titanium dioxide nanoparticles (CS-NPs coated TiO2). Coating was being done by chitosan nanoparticles (CS-NPs) using ionic gelation method. Aqueous solution of Moringa concanensis leaf extract was used to synthesize titanium dioxide nanoparticles (TiO2 NPs). The synthesized nanoformulations were characterized by using XRD, SEM, and FTIR. X-ray diffraction (XRD) analysis indicated the crystalline phase of TiO2 NPs and CS-NPs coated TiO2 NPs. Scanning Electron Microscopy (SEM) confirmed spherical shaped nanoparticles size of chitosan NPs ranging from 19–25 nm and TiO2 NPs 35–50 nm. Thesize of CS-NPs coated TiO2 NPs was in the range of 65–75 nm. The UV-Vis Spectra and band gap values illustrated the red shift in CS-NPs coated TiO2 NPs. Fourier transform infrared (FTIR) spectroscopy confirmed the linkages between TiO2 NPs and chitosan biopolymer, Zeta potential confirmed the stability of CS-NPs coated TiO2 NPs by showing 95 mV peak value. In-vitro antibacterial activity of CS-NPs coated TiO2 NPs and Uncoated TiO2 NPs was evaluated by disc diffusion method against PDR strain of E. coli isolated from mastitic milk samples. The antibacterial activity of all the synthesized nanoformulations were noted and highest antibacterial activity was shown by CS-NPs coated TiO2-NPs against pandrug resistant (PDR) E. coli strain with the prominent zone of inhibition of 23 mm. Morphological changes of E. coli cells after the treatment with MIC concentration (0.78 μg/ml) of CS-NPs coated TiO2 NPs were studied by transmission electron microscopy TEM showedrigorous morphological defectand has distorted the general appearance of the E. coli cells. Cytotoxicity (HepG2 cell line) and hemolytic (human blood) studies confirmed nontoxic/biocompatible nature of CS-NPs coated biologically synthesized TiO2 NPs. The results suggested that biologically synthesized and surface modified TiO2 NPs by mucoadhesive polysaccharides (e.g. chitosan) coating would be an effective and non-toxic alternative therapeutic agent to be used in livestock industry to control drug resistant veterinary pathogens.

In Vitro Antibacterial Activity and Mechanism of Monocaprylin against Escherichia coli and Staphylococcus aureus

2018 ◽  
Vol 81 (12) ◽  
pp. 1988-1996 ◽  
Author(s):  
JIANYU WANG ◽  
MAOMAO MA ◽  
JUN YANG ◽  
LONG CHEN ◽  
PING YU ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Membrane Potential ◽  
Cell Membrane ◽  
Sodium Benzoate ◽  
Rapid Change ◽  
Potassium Sorbate ◽  
E Coli

ABSTRACT In the present study, the antibacterial activity of monocaprylin in comparison with sodium benzoate and potassium sorbate against Staphylococcus aureus and Escherichia coli was assessed by measuring MIC, MBC, effect of pH on MIC, and incubation temperature on bactericidal efficacy. Results showed that monocaprylin exhibited an excellent antibacterial activity against both strains, with the lowest MIC and MBC of 1.28 mg/mL. A MIC of monocaprylin remained unchanged despite the pH values of culture medium, ranging from 5 to 9, unlike that of potassium sorbate or sodium benzoate. Furthermore, monocaprylin at MBC effectively reduced the population of E. coli and S. aureus by &gt;5.5 log CFU/mL at 25°C within 6 h and decreased E. coli by approximately 5.0 log CFU/mL and S. aureus by 2.9 log CFU/mL at 12 h. The underlying mechanism of monocaprylin was then investigated by measuring β-galactosidase activity, membrane potential, release of cellular contents, scanning electron microscopy, and transmission electron microscopy observations. Results indicated that monocaprylin killed E. coli by the rapid change in permeability and integrity of cell membrane, leading to decline of membrane potential, leakage of nucleic acids and proteins, and ultimately cell membrane disintegration and lysis. On the other hand, monocaprylin might exert its antibacterial activity against S. aureus mainly by diffusing across the cell wall, collapsing the cell membrane, and disturbing the order of intracellular contents. These findings indicated that monocaprylin had better antibacterial ability compared with traditional synthetic preservatives and might be a potential antibacterial additive independent of pH.

Antibacterial activity and in vitro cytotoxicity evaluation of alginate-AgNP fibers

2016 ◽  
Vol 87 (11) ◽  
pp. 1377-1386 ◽  
Author(s):  
Xihui Zhao ◽  
Qun Li ◽  
Xiaowen Li ◽  
Yanzhi Xia ◽  
Bing Wang ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Treatment Time ◽  
Biological Activities ◽  
In Vitro Cytotoxicity ◽  
Cell Counting ◽  
Logarithmic Phase ◽  
E Coli ◽  
Alginate Fibers ◽  
And Staphylococcus Aureus

Biopolymer nanocomposites containing metal nanoparticles have attracted much attention due to their excellent properties and broad applications. In this work, alginate fibers embedded with silver nanoparticles (AgNPs) were prepared. The as-obtained alginate-AgNP fibers exhibited antibacterial activity against both Gram microorganisms of model microbes Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). A growth kinetic study with S. aureus and E. coli displayed the inhibition of bacterial growth at the logarithmic phase. The cytotoxic effect of the fibers in human cervical cancer (HeLa) cells was assessed by cell counting kit-8 (CCK-8) assay and flow cytometry. The as-prepared alginate-AgNP fibers, particularly with high amount and long treatment time, showed high cell-killing efficiency. These findings emphasize that such alginate-AgNP fibers with multifaceted biological activities are a promising material for applications in the textile or biomedical fields.

scholarly journals Towards understanding the antibacterial activity of Ag nanoparticles: electron microscopy in the analysis of the materials-biology interface in the lung

2015 ◽  
Vol 2 (4) ◽  
pp. 312-326 ◽  
Author(s):  
M. López-Heras ◽  
I. G. Theodorou ◽  
B. F. Leo ◽  
M. P. Ryan ◽  
A. E. Porter
Keyword(s):  
Electron Microscopy ◽  
Antibacterial Activity ◽  
Ag Nanoparticles ◽  
Bacterial Infections ◽  
Pulmonary System

Bacterial infections of the pulmonary system are increasing.

scholarly journals Uji Fitokimia dan Aktivitas Antibakteri Tumbuhan Pranajiwa (Euchresta horsfieldii (Lesch.) Benn.)

2018 ◽  
Vol 12 (2) ◽  
pp. 223
Author(s):  
Amalia Indah Prihantini ◽  
Krisnawati Krisnawati ◽  
Anita Apriliani Dwi Rahayu ◽  
Yosephin Martha Maria Anita Nugraheni ◽  
Gipi Samawandana
Keyword(s):  
Fatty Acids ◽  
Antibacterial Activity ◽  
Medicinal Plant ◽  
Antibacterial Agents ◽  
Phytochemical Analysis ◽  
Activity Assay ◽  
Alternative Source ◽  
E Coli ◽  
Escherchia Coli ◽  
Main Components

Euchresta horsfieldii merupakan tanaman obat yang dikenal di Nusa Tenggara Barat dan Bali sebagai pranajiwa. Pada penelitian ini telah dilakukan analisis fitokimia dan aktivitas antibakteri dari akar, batang, daun, dan biji pranajiwa. Pengujian aktivitas antibakteri dilakukan terhadap bakteri Bacilus subtilis Inacc-B334, Staphylococccus aureus Inacc-B4, dan Escherchia coli Inacc-B5. Hasil analisis fitokimia menunjukkan bahwa alkaloid sebagai komponen senyawa yang paling dominan pada pranajiwa dan terdeteksi di setiap bagian tanaman. Bagian akar pranajiwa terdeteksi memiliki komponen senyawa yang paling bervariasi seperti alkaloid, tanin, flavonoid, saponin, dan terpenoid. Analisis GC-MS dari batang, akar, dan biji pranajiwa menunjukkan mome inositol, sophoridane, dan asam lemak seperti asam palmitat dan asam stearat sebagai komponen utamanya. Adapun uji aktivitas antibakteri pranajiwa menunjukkan bagian batang dan akar memiliki aktivitas antibakteri terhadap S. aureus Inacc-B4 dan E. coli Inacc B-5, sedangkan bagian biji memiliki aktivitas antibakteri terhadap B. subtilis Inacc-B-334 dan S. aureus Inacc-B4. Hasil-hasil penelitian tersebut dapat mendukung penelitian terkait potensi E. horsfieldii sebagai sumber alternatif obat antibakteri. Phytochemical Test and Antibacterial Activity of Pranawija (Euchresta horsfieldii (Lesch.) Benn.)AbstractEuchresta horsfieldii is a medicinal plant known in West Nusa Tenggara and Bali as pranajiwa. This study investigated phytochemical analysis and antibacterial activity of roots, stems, leaves, and seeds of E. horsfieldii. The samples were analyzed for their antibacterial activity against Bacilus subtilis Inacc-B334, Staphylococccus aureus Inacc-B4, and Escherchia coli Inacc-B5. The phytochemistry result indicated that alkaloids was the most dominant constituent of E. horsfieldii as it was detected in all parts of the plant. GC-MS analysis of the stems, roots, and seeds showed mome inositol, sophoridane, and fatty acids such as palmitic acid and strearic acid as the main components. The roots had the most varied constituents with detection of alkaloids, tannins, flavonoids, saponins, and terpenoids. Further, antibacterial activity assay showed that the stems and roots had antibacterial activity against S. aureus Inacc-B4 and E. coli Inacc B-5, whereas the seeds had antibacterial activity against B. subtilis Inacc-B-334 and S. aureus InaccB4. The result of the present study supports the investigation on potentiality of E. horsfieldii as alternative source for antibacterial agents.

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