Mononuclear metal (II) complexes of a Bis(organoamido)phosphate ligand with antimicrobial activities against Escherichia coli

2017 ◽  
Vol 31 (12) ◽  
pp. e3821 ◽  
Author(s):  
Souvik Pal ◽  
Abhrajyoti Tarafdar ◽  
Alok Sinha ◽  
Asamanjoy Bhunia ◽  
Klaus Harms ◽  
...  
2011 ◽  
Vol 74 (5) ◽  
pp. 820-825 ◽  
Author(s):  
YOEN JU PARK ◽  
JINRU CHEN

This study was conducted to evaluate the abilities of five neutralizing agents, Dey-Engley (DE) neutralizing broth (single or double strength), morpholinepropanesulfonic acid (MOPS) buffer, phosphate-buffered saline (PBS), and sodium thiosulfate buffer, in mitigating the activities of acetic or lactic acid (2%) and an alkaline or acidic sanitizer (a manufacturer-recommended concentration) againt the cells of Shiga toxin–producing Escherichia coli (STEC; n = 9). To evaluate the possible toxicity of the neutralizing agents to the STEC cells, each STEC strain was exposed to each of the neutralizing agents at room temperature for 10 min. Neutralizing efficacy was evaluated by placing each STEC strain in a mixture of sanitizer and neutralizer under the same conditions. The neutralizing agents had no detectable toxic effect on the STEC strains. PBS was least effective for neutralizing the activity of selected organic acids and sanitizers. Single-strength DE and sodium thiosulfate neutralized the activity of both acetic and lactic acids. MOPS buffer neutralized the activity of acetic acid and lactic acid against six and five STEC strains, respectively. All neutralizing agents, except double-strength DE broth, had a limited neutralizing effect on the activity of the commercial sanitizers used in the study. The double-strength DE broth effectively neutralized the activity of the two commercial sanitizers with no detectable toxic effects on STEC cells.


2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Driss Ousaaid ◽  
Hassan Laaroussi ◽  
Meryem Bakour ◽  
Hayat Ennaji ◽  
Badiaa Lyoussi ◽  
...  

This study was designed to assess the antimicrobial potencies of apple vinegar against pathogenic microbes. The acidity and total phenolic content were carried out by titration with NaOH 0.1 N and the Folin–Ciocalteu method, respectively, while the spread plate method, agar well diffusion, and MIC assays were used to determine the antimicrobial activities of different vinegar samples. Acidity and phenolic content were dependent on the variety, where the highest values were observed in S2 with 4.02 ± 0.04% and 1.98 ± 0.05 mg GAE/mL for acidity and total phenolic content, respectively. The spread plate method revealed that samples S1 and S2 obtained from the Red delicious variety and Golden delicious variety, respectively, inhibit the growth of all tested strains, while S3 obtained from different varieties and S4 obtained from the Gala royal variety inhibit only two microbes (Escherichia coli and Vibrio cholerae). Sample S1 presented moderate antimicrobial effect against all examined strains with a diameter of inhibition ranging from 11 ± 0.7 to 19 ± 0.5 mm and with MIC values ranging between 1/2 and 1/100. The findings of the current study confirm the usefulness of apple vinegar as a natural sanitizer that inhibits the growth of pathogenic microbes.


Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1588 ◽  
Author(s):  
Bi Foua Claude Alain Gohi ◽  
Hong-Yan Zeng ◽  
Xiao-Ju Cao ◽  
Kai-Min Zou ◽  
Wenlin Shuai ◽  
...  

Hybrid nano-supra molecular structured materials can boost the functionality of nano- or supra-molecular materials by providing increased reactivity and conductivity, or by simply improving their mechanical stability. Herein, the studies in materials science exploring hybrid systems are investigated from the perspective of two important related applications: healthcare and food safety. Interfacing phase strategy was applied, and ZnAl layered double hydroxide-chitosan hybrids, prepared by the urea method (U-LDH/CS), were successfully synthesized under the conditions of different chitosan(CS) concentrations with a Zn/Al molar ratio of 5.0. The structure and surface properties of the U-LDH/CS hybrids were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectrometer(FTIR), scanning electronmicroscopy (SEM), ultravioletvisible (UV-Vis), and zero point charge (ZPC) techniques, where the effect of CS concentration on the structure and surface properties was investigated. The use of the U-LDH/CS hybrids as antimicrobial agents against Escherichia coli, Staphylococcus aureus, and Penicillium cyclopium was investigated in order to clarify the relationship between microstructure and antimicrobial ability. The hybrid prepared in a CS concentration of 1.0 g∙L−1 (U-LDH/CS1) exhibited the best antimicrobial activity and exhibited average inhibition zones of 24.2, 30.4, and 22.3mm against Escherichia coli, Staphylococcus aureus, and Penicillium cyclopium, respectively. The results showed that the appropriate addition of CS molecules could increase antimicrobial ability against microorganisms.


2018 ◽  
Vol 13 (4) ◽  
pp. 1934578X1801300 ◽  
Author(s):  
Ngonye Keroletswe ◽  
Runner R. T. Majinda ◽  
Ishmael B. Masesane

One new 3-prenyl-2-flavene, named baphiflavene A, 1, and eleven known compounds, 2-12, were isolated and reported for the first time from Baphia massaiensis using several chromatographic techniques. Their structures were elucidated using different spectroscopic techniques; 1D and 2D-NMR, HRMS, GC-MS, UV/Vis, FTIR and by comparison with literature data. The isolates were tested against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli and Candida albicans to establish their preliminary antimicrobial activities. The results revealed that compound 1 had moderate activities against both Gram positive ( B. subtilis and S. aureus) and Gram negative ( E. coli and P. aeruginosa) bacteria, and good activity against C. albicans with inhibition zones of 10–23 mm (compared to 19 mm for chloramphenicol and miconazole standards). To the best of our knowledge, this is the first phytochemical work reported on Baphia massaiensis.


Author(s):  
MAJOLAGBE O. N. ◽  
AINA D. A. ◽  
OMOMOWO I. O. ◽  
THOMAS A.

Objective: To determine the antimicrobial potentials of secondary metabolite of soil fungi and predict their 3D structure and molecular identity. Methods: Pure soil fungi were isolated from soil samples and cultured under submerged fermentation (Smf) for their metabolites using Potato Dextrose Agar and Broth. The secondary metabolites of the isolated fungi were obtained intracellularly after 21 d of incubation in a rotary shaker incubator. The antimicrobial potentials of the metabolites were investigated against four (4) clinical isolates, namely: Staphylococcus aureus, Klebsiella spp, Candida albicans and Escherichia coli. These soil fungi were further characterized to the molecular level and their evolutionary relationships established using bioinformatics tools. Protein structure of each of the fungi isolates was predicted using PHYRE-2. Results: Out of all the soil fungi isolated, the metabolite of Aspergillus aculeatus showed the highest antimicrobial activities against Staphylococcus aureus (23.00±2.34 mm), Escherichia coli (9.00±1.44 mm) and Klebsiella spp (24.00±3.45 mm). The 3D protein structure predicted showed that each of the organisms consists of different amino-acid compositions such as: serine, tyrosine, proline, arginine, glycine, phenylalanine leucine with other notable biological properties. Conclusion: The work revealed that secondary metabolites of the isolated fungi carry an important role in combating infectious agents thereby, providing roadmaps for the biosynthesis of many synthetic and semi-synthetic drugs and bio-products which are environmentally friendly.


2020 ◽  
Vol 21 (2) ◽  
pp. 106-113
Author(s):  
D.K. Adeyemi ◽  
A.O. Adeluola ◽  
M.J. Akinbile ◽  
O.O. Johnson ◽  
G.A. Ayoola

Background: Nanotechnology offers an advantage as a green route for synthesis of metal nanoparticles (NPs) with plant extracts as capping agent. Spondias mombin is a fruit-bearing tree and its leaf extracts have been reported to possess anxiolytic, hypoglycaemic, antiepileptic, antipsychotic, sedative, antioxidant, and antimicrobial properties. The objective of the study is to determine the antibacterial potential of a simple non-toxic product of green synthesis of metallic (Ag, Zn and Cu) nanoparticles using the leaf of Spondias mombin aqueous extracts (SMAE) as a reducing and capping agents of the metal ions.Methodology: Nanoparticles were characterized by UV visible spectrophotometeric analysis, Fourier Transform Infra-Red (FT-IR) spectrophotometer and scanning electron microscope (SEM). Antimicrobial activities of synthesized NPs against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa were determined by agar well diffusion technique.Results: The synthesized NPs varied in colour from dark brown to green and appears dominantly spherical, occasionally rod or triangular shaped with size ranging from 65-90 nm. UV spectroscopy absorption spectra of Ag, Zn and Cu NPs had absorbance peak at 267, 262 and 765 nm respectively. FT-IR spectrometry of Zn NP, Cu NP, and SMAE gave wave number ranging from 895.71-3320.67, 747.02-3225.45 and 658.25-3674.49 respectively. FT-IR analysis showed that SMAE acted as reducing and stabilizing agent while the NPs exhibited lower energy absorption band when compared to the plant extract. The NPs demonstrated higher antimicrobial activities against S. aureus than Ps. aeruginosa and E. coli. The antimicrobial activity was higher with copper NP than Ag and Zn NPs, and also higher than SMAE.Conclusion: The result from this study presents an indication for an alternative means for development of novel antimicrobial agents for clinical and biotechnological applications.Keywords: synthesis, nanoparticles, FT-IR, UV-visible spectrophotometry, antibacterial activitiesFrench Title: Synthèse verte de nanoparticules d'Ag, de Zn et de Cu à partir d'extrait aqueux de feuilles de Spondias mombin et évaluation de leur activité antibactérienneContexte: La nanotechnologie offre un avantage en tant que voie verte pour la synthèse de nanoparticules métalliques (NP) avec des extraits de plantes comme agent de coiffage. Spondias mombin est un arbre fruitier et ses extraits de feuilles possèdent des propriétés anxiolytiques,  hypoglycémiques, antiépileptiques, antipsychotiques, sédatives,  antioxydantes et antimicrobiennes. L’objectif de l’étude est de déterminer le potentiel antibactérien d’un simple produit non toxique de synthèse verte de nanoparticules métalliques (Ag, Zn et Cu) à l’aide de la feuille d’extraits aqueux de Spondias mombin (SMAE) en tant qu’agent réducteur et coiffant de la ions métalliques.Méthodologie: Les nanoparticules ont été caractérisées par analyse  spectrophotométrique UV visible, spectrophotomètre à transformée de Fourier infrarouge (FT-IR) et microscope électronique à balayage (MEB). Lesactivités antimicrobiennes de NP synthétisées contre Escherichia coli, Staphylococcus aureus et Pseudomonas aeruginosa ont été déterminées par une technique de diffusion sur puits d’agar.Résultats: Les NP synthétisés ont une couleur allant du brun foncé au vert et apparaissent principalement sphériques, parfois en bâtonnets ou en triangles, avec des tailles allant de 65 à 90 nm. Les spectres  d'absorption par spectroscopie UV des NP Ag, Zn et Cu présentaient des pics  d'absorbance à 267, 262 et 765 nm respectivement. La spectrométrie FT-IR de Zn NP, Cu NP et SMAE a donné un nombre d'onde allant de 895,71 à 3320,67, 747,02 à 3225,45 et 658,25 à 3674,49 respectivement. L'analyse FT-IR a montré que le SMAE agissait en tant qu'agent réducteur et  stabilisant, alors que les NP présentaient une bande d'absorption d'énergie inférieure à celle de l'extrait de plante. Les NP ont démontré des activités antimicrobiennes plus élevées contre S. aureus que Ps. aeruginosa et E. coli. L'activité antimicrobienne était plus élevée avec les NP en cuivre que dans les NP Ag et Zn, et également supérieure à celle du SMAE.Conclusion: le résultat de cette étude présente une indication d'un autre moyen de développement de nouveaux agents antimicrobiens pour des applications cliniques et biotechnologiques.Mots-clés: synthèse, nanoparticules, FT-IR, spectrophotométrie UV-visible, activités antibactériennes 


2018 ◽  
Vol 11 (1) ◽  
pp. 174-178
Author(s):  
Muhammad Saleh Salga ◽  
Sani Sabo

A series of four mixed ligand complexes synthesized by reacting benzoylacetone and salicylaldehyde with different metal chlorides in ethanolic medium, were tested for their antimicrobial studies and indicated that the compounds are active against microorganisms used (Escherichia coli, Staphylococcus aureus, and Candida albicans) when compared with the activity of the reference or standard drugs (Erythromycin and Suptrin).Keywords: Antimicrobial, Synthesis, Ligands, Complexes


2010 ◽  
Vol 76 (6) ◽  
pp. 1967-1974 ◽  
Author(s):  
Shuyu Hou ◽  
Zhigang Liu ◽  
Anne W. Young ◽  
Sheron L. Mark ◽  
Neville R. Kallenbach ◽  
...  

ABSTRACT Biofilms are sessile microbial communities that cause serious chronic infections with high morbidity and mortality. In order to develop more effective approaches for biofilm control, a series of linear cationic antimicrobial peptides (AMPs) with various arginine (Arg or R) and tryptophan (Trp or W) repeats [(RW) n -NH2, where n = 2, 3, or 4] were rigorously compared to correlate their structures with antimicrobial activities affecting the planktonic growth and biofilm formation of Escherichia coli. The chain length of AMPs appears to be important for inhibition of bacterial planktonic growth, since the hexameric and octameric peptides significantly inhibited E. coli growth, while tetrameric peptide did not cause noticeable inhibition. In addition, all AMPs except the tetrameric peptide significantly reduced E. coli biofilm surface coverage and the viability of biofilm cells, when added at inoculation. In addition to inhibition of biofilm formation, significant killing of biofilm cells was observed after a 3-hour treatment of preformed biofilms with hexameric peptide. Interestingly, treatment with the octameric peptide caused significant biofilm dispersion without apparent killing of biofilm cells that remained on the surface; e.g., the surface coverage was reduced by 91.5 ± 3.5% by 200 μM octameric peptide. The detached biofilm cells, however, were effectively killed by this peptide. Overall, these results suggest that hexameric and octameric peptides are potent inhibitors of both bacterial planktonic growth and biofilm formation, while the octameric peptide can also disperse existing biofilms and kill the detached cells. These results are helpful for designing novel biofilm inhibitors and developing more effective therapeutic methods.


1994 ◽  
Vol 302 (2) ◽  
pp. 535-538 ◽  
Author(s):  
J Alvarez-Bravo ◽  
S Kurata ◽  
S Natori

Previously, we identified a core undecapeptide of sapecin B having antimicrobial activity. Based on the structure of this peptide, we systematically synthesized peptides consisting of terminal basic motifs and internal oligo-leucine sequences and examined their antimicrobial activities. Of these peptides, RLKLLLLLRLK-NH2 and KLKLLLLLKLK-NH2 were found to have potent microbicidal activity against Staphylococcus aureus, Escherichia coli, methicillin-resistant S. aureus and Candida albicans in liquid medium. We also synthesized the D-enantiomer of KLKLLLLLKLK-NH2. This enantiomer was resistant to tryptic digestion and persisted longer in the culture medium, showing greater antimicrobial activity than the original peptide.


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