Synthesis, characterization and biological evaluation of cationic porphyrin–terpyridine derivatives

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.

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Synthesis and Antimicrobial Evaluations of Sulfur Inserted Fluoro-Benzimidazoles

Asian Journal of Chemistry ◽

10.14233/ajchem.2021.23174 ◽

2021 ◽

Vol 33 (7) ◽

pp. 1525-1529

Author(s):

Parmesh Kumar Dwivedi ◽

Devdutt Chaturvedi

Keyword(s):

Antimicrobial Agents ◽

Bacterial Strains ◽

Substituted Anilines ◽

Gram Positive ◽

Gram Negative ◽

E Coli ◽

New Compounds ◽

Derivatives Of ◽

Multiple Step

A new series of fluorinated sulfur inserted benzimidazole analogues Za-i were synthesized and characterized. The new compounds were screened for their antimicrobial and antioxidant potential. The synthesized compounds were obtained by multiple step synthesis, initiating from the synthesis of 5-(difluoromethoxy)-1H-benzimidazole-2-thiol X. The compounds Ya-i prepared by reacting differently substituted anilines with chloroacetylchloride and triethylamine in DMF. Finally, the compound X was reacted with different derivatives of 2-chloro-N-phenylacetamide resulting in formation of titled compounds Za-i. The synthesized compounds (Za-Zi) were characterized by spectral analysis viz.1H & 13C NMR, mass spectra, elemental analysis and IR. The in vitro antimicrobial potential against Gram-positive (S. aureus and E. faecalis) and Gram-negative bacterial (E. coli and P.aeruginosa) strains as well as fungi (A. niger and C. albicans) was recorded for the obtained compounds. Some of the compounds exhibited encouraging results (in MIC) against Gram-positive and Gram-negative bacterial strains. These studies thus suggest that the designed sulfur inserted fluoro-benzimidazoles scaffold may serve as new promising template for further amplification as antimicrobial agents.

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Synthesis and biological evaluation of novel acyclic and cyclic glyoxamide based derivatives as bacterial quorum sensing and biofilm inhibitors

Organic & Biomolecular Chemistry ◽

10.1039/c7ob01011g ◽

2017 ◽

Vol 15 (27) ◽

pp. 5743-5755 ◽

Cited By ~ 8

Author(s):

Shashidhar Nizalapur ◽

Onder Kimyon ◽

Eugene Yee ◽

Mohan M. Bhadbhade ◽

Mike Manefield ◽

...

Keyword(s):

Quorum Sensing ◽

Biofilm Formation ◽

Biological Evaluation ◽

Gram Negative Bacteria ◽

Gram Negative ◽

E Coli ◽

Sensing Mechanism ◽

Bacterial Quorum Sensing ◽

Bacterial Quorum ◽

Synthesis And Biological Evaluation

Novel acyclic and cyclic glyoxamides that inhibited quorum sensing mechanism and biofilm formation in Gram-negative bacteria such as P. aeruginosa and E. coli.

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Cationic Pyrrolidine/Pyrroline-Substituted Porphyrins as Efficient Photosensitizers against E. coli

Molecules ◽

10.3390/molecules26020464 ◽

2021 ◽

Vol 26 (2) ◽

pp. 464

Author(s):

Bruno M. F. Ladeira ◽

Cristina J. Dias ◽

Ana T. P. C. Gomes ◽

Augusto C. Tomé ◽

Maria G. P. M. S. Neves ◽

...

Keyword(s):

Detection Limit ◽

Visible Light ◽

Singlet Oxygen ◽

Irradiation Time ◽

Azomethine Ylide ◽

Dipolar Cycloaddition ◽

Drastic Reduction ◽

Gram Negative ◽

Cationic Porphyrin ◽

E Coli

New porphyrin–pyrrolidine/pyrroline conjugates were prepared by revisiting 1,3-dipolar cycloaddition reactions between a porphyrinic azomethine ylide and a series of dipolarophiles. Cationic conjugates obtained by alkylation of the pyrrolidine/pyrroline cycloadducts showed ability to generate singlet oxygen and to produce iodine in presence of KI when irradiated with visible light. Some of the cationic derivatives showed photobactericidal properties towards a Gram-negative bioluminescent E. coli. In all cases, these features were significantly improved using KI as coadjutant, allowing, under the tested conditions, the photoinactivation of the bacterium until the detection limit of the method with a drastic reduction of the required photosensitizer concentration and irradiation time. The obtained results showed a high correlation between the ability of the cationic porphyrin derivative to produce singlet oxygen and iodine and its E. coli photoinactivation profile.

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Biomimetic Enterobactin Analogue Mediates Iron-Uptake and Cargo Transport into E. coli and P. aeruginosa

10.26434/chemrxiv.13383125.v1 ◽

2020 ◽

Author(s):

Robert Zscherp ◽

Janetta Coetzee ◽

Johannes Vornweg ◽

Jörg Grunenberg ◽

jennifer herrmann ◽

...

Keyword(s):

Outer Membrane ◽

Density Functional ◽

Initial Density ◽

Molecular Size ◽

Biological Evaluation ◽

Permeability Barrier ◽

Promoting Effect ◽

Design Synthesis ◽

Gram Negative ◽

E Coli

The design, synthesis and biological evaluation of the artificial enterobactin analogue EntKL and several fluorophore-conjugates thereof are described. EntKL provides an attachment point for cargos such as fluorophores or antimicrobial payloads. Corresponding conjugates are recognized by outer membrane siderophore receptors of Gram-negative pathogens and retain the natural hydrolyzability of the tris-lactone backbone, known to be key for uptake into the cytosol. Initial density-functional theory (DFT) calculations of the free energies of solvation (ΔG(sol)) and relaxed Fe-O force constants of the corresponding [Fe-EntKL]3- complexes indicated a similar iron binding constant compared to natural enterobactin (Ent). The synthesis of EntKL was achieved via an iterative assembly based on a 3-hydroxylysine building block over 14 steps with an overall yield of 3%. A series of growth recovery assays under iron-limiting conditions with Escherichia coli and Pseudomonas aeruginosa mutant strains that are defective in natural siderophore synthesis revealed a potent concentration-dependent growth promoting effect of EntKL similar to natural Ent. Additionally, four cargo-conjugates differing in molecular size were able to restore growth of E. coli indicating an uptake into the cytosol. P. aeruginosa displayed a stronger uptake promiscuity as six different cargo-conjugates were found to restore growth under iron-limiting conditions. Imaging studies utilizing BODIPYFL-conjugates, demonstrated the ability of EntKL to overcome the Gram-negative outer membrane permeability barrier and thus deliver molecular cargos via the bacterial iron transport machinery of E. coli and P. aeruginosa.

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Influence of Cationic meso-Substituted Porphyrins on the Antimicrobial Photodynamic Efficacy and Cell Membrane Interaction in Escherichia coli

International Journal of Molecular Sciences ◽

10.3390/ijms20010134 ◽

2019 ◽

Vol 20 (1) ◽

pp. 134 ◽

Cited By ~ 7

Author(s):

Alexandra N. Hurst ◽

Beth Scarbrough ◽

Roa Saleh ◽

Jessica Hovey ◽

Farideh Ari ◽

...

Keyword(s):

Escherichia Coli ◽

Cell Membrane ◽

Gram Negative Bacteria ◽

Gram Negative ◽

Cationic Porphyrins ◽

Cationic Porphyrin ◽

E Coli ◽

Live Cell Microscopy ◽

The Difference ◽

The Hill

Photodynamic inactivation (PDI) is a non-antibiotic option for the treatment of infectious diseases. Although Gram-positive bacteria have been shown to be highly susceptible to PDI, the inactivation of Gram-negative bacteria has been more challenging due to the impermeability properties of the outer membrane. In the present study, a series of photosensitizers which contain one to four positive charges (1–4) were used to evaluate the charge influence on the PDI of a Gram-negative bacteria, Escherichia coli (E. coli), and their interaction with the cell membrane. The dose-response PDI results confirm the relevance of the number of positive charges on the porphyrin molecule in the PDI of E. coli. The difference between the Hill coefficients of cationic porphyrins with 1–3 positive charges and the tetra-cationic porphyrin (4) revealed potential variations in their mechanism of inactivation. Fluorescent live-cell microscopy studies showed that cationic porphyrins with 1–3 positive charges bind to the cell membrane of E. coli, but are not internalized. On the contrary, the tetra-cationic porphyrin (4) permeates through the membrane of the cells. The contrast in the interaction of cationic porphyrins with E. coli confirmed that they followed different mechanisms of inactivation. This work helps to have a better understanding of the structure-activity relationship in the efficiency of the PDI process of cationic porphyrins against Gram-negative bacteria.

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Antimicrobial activity of novel 1-[(2,4-(di-tert-butylphenoxy))-3-dialkylamino-2-propanol] derivativesy

One Health & Risk Management ◽

10.38045/ohrm.2021.3.04 ◽

2021 ◽

Vol 2 (3) ◽

pp. 27-33

Author(s):

Nina VRYNCHANU ◽

Yurii KOROTKIJ ◽

Nataliia HRYNCHUK ◽

Irina BOIKO ◽

Elena SMERTENKO ◽

...

Keyword(s):

Antimicrobial Activity ◽

High Efficiency ◽

Gentian Violet ◽

Inhibitory Effect ◽

Chronic Infections ◽

E Coli ◽

External Stresses ◽

Antibacterial And Antifungal ◽

New Compounds ◽

Adsorption Desorption

Introduction. The microbial biofilm-forming ability is one of the major aspects of the emerging issue of antibiotic resistance, which makes them tolerant to antibiotics and host defense systems and other external stresses, thus contributing to persistent chronic infections. A series of relevant studies confirmed the high efficiency of aminopropanol derivatives as potential antibacterial and antifungal agents. This present study was aimed to evaluate the antimicrobial activity of new 1-[(2,4-(di-tert-butylphenoxy))-3-dialkylamino-2-propanol] derivatives on the planktonic bacterial/fungal cells and biofilms. Material and methods. The minimum inhibitory concentrations (MIC) of the new compounds were determined by a standard method, along with their effects on biofilms estimated via the gentian violet adsorption-desorption assay.Results. The КVM-219 compound showed the most pronounced effect on planktonic bacterial and fungal cells. The MIC values ranged between 0.78 μg/mL to 12.5 μg/mL, depending on the microbial strain. The KVM-316 compound exhibited the strongest inhibitory effect on biofilms, thus preventing their formation by S. aureus (96.1%), E. coli (57.2%), and P. aeruginosa (96.1%). Conclusions. The 15 newly synthesized 1-[(2,4-(di-tert-butylphenoxy))-3-dialkylamino-2-propanol] derivatives revealed marked antibacterial and antifungal effects on planktonic microorganisms. Most of these compounds showed a strain-specific inhibition of biofilm formation by at least 50% for S. aureus 222, E. coli 311, P. aeruginosa 449 and C. glabrata 404 strains.

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Synthesis and Study of Some Newer Analogues ofQuinolin-8-ol as Potent Antimicrobial Agents

E-Journal of Chemistry ◽

10.1155/2008/249245 ◽

2008 ◽

Vol 5 (s1) ◽

pp. S1008-S1014

Author(s):

Jyoti Sharma ◽

Sabir Hussain ◽

Mohammad Amir

Keyword(s):

Antimicrobial Activity ◽

Antibacterial Activity ◽

Antimicrobial Agents ◽

Antifungal Agents ◽

Gram Negative ◽

E Coli ◽

H Nmr ◽

Gram Negative Organisms ◽

New Compounds

New series of 4-(substituted phenyl)-5-[(quinolin-8-yloxy) methyl]-4H-1,2,4-triazole-3-thiol(4a-c),N³-(4-substituted phenyl)-5-[(quinolin-8-yloxy) methyl]-4H-1,2,4-triazole-3,4-diamine(5a-c)andN-(4-substituted phenyl)-5-[(quinolin-8-yloxy) methyl]-1,3,4-thiadiazol-2-amine(6a-g)have been synthesized and the structures of the new compounds were established on the basis of IR,1H NMR spectral data.In vitroantimicrobial activity (MIC activity) was evaluated and compared with standard drugs of loxacin and ketoconazole. Compounds5aand6ein the series have shown interesting antibacterial activity against bothS. aureus(gram-positive) andE. coli(gram-negative) organisms. In this paper, we also describe studies leading to identification of antifungal agents. In the gratifying result, most of the compounds were found to have moderate antimicrobial activity.

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Biomimetic Enterobactin Analogue Mediates Iron-Uptake and Cargo Transport into E. coli and P. aeruginosa

10.26434/chemrxiv.13383125 ◽

2020 ◽

Author(s):

Robert Zscherp ◽

Janetta Coetzee ◽

Johannes Vornweg ◽

Jörg Grunenberg ◽

jennifer herrmann ◽

...

Keyword(s):

Outer Membrane ◽

Density Functional ◽

Initial Density ◽

Molecular Size ◽

Biological Evaluation ◽

Permeability Barrier ◽

Promoting Effect ◽

Design Synthesis ◽

Gram Negative ◽

E Coli

The design, synthesis and biological evaluation of the artificial enterobactin analogue EntKL and several fluorophore-conjugates thereof are described. EntKL provides an attachment point for cargos such as fluorophores or antimicrobial payloads. Corresponding conjugates are recognized by outer membrane siderophore receptors of Gram-negative pathogens and retain the natural hydrolyzability of the tris-lactone backbone, known to be key for uptake into the cytosol. Initial density-functional theory (DFT) calculations of the free energies of solvation (ΔG(sol)) and relaxed Fe-O force constants of the corresponding [Fe-EntKL]3- complexes indicated a similar iron binding constant compared to natural enterobactin (Ent). The synthesis of EntKL was achieved via an iterative assembly based on a 3-hydroxylysine building block over 14 steps with an overall yield of 3%. A series of growth recovery assays under iron-limiting conditions with Escherichia coli and Pseudomonas aeruginosa mutant strains that are defective in natural siderophore synthesis revealed a potent concentration-dependent growth promoting effect of EntKL similar to natural Ent. Additionally, four cargo-conjugates differing in molecular size were able to restore growth of E. coli indicating an uptake into the cytosol. P. aeruginosa displayed a stronger uptake promiscuity as six different cargo-conjugates were found to restore growth under iron-limiting conditions. Imaging studies utilizing BODIPYFL-conjugates, demonstrated the ability of EntKL to overcome the Gram-negative outer membrane permeability barrier and thus deliver molecular cargos via the bacterial iron transport machinery of E. coli and P. aeruginosa.

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Disinfection of Fruits with Activated Water

JOURNAL OF ADVANCES IN AGRICULTURE ◽

10.24297/jaa.v10i0.8462 ◽

2019 ◽

Vol 10 ◽

pp. 1864-1872

Author(s):

Prof. Teodora P. Popova

Keyword(s):

Antimicrobial Activity ◽

Aqueous Solutions ◽

Antimicrobial Properties ◽

The Other ◽

Gram Negative Bacteria ◽

High Antimicrobial Activity ◽

Gram Negative ◽

E Coli ◽

Number Of Microorganisms ◽

Lower Effect

The effect of ionized aqueous solutions (anolytes and catholyte) in the processing of fruits (cherries, morellos, and strawberries) for decontamination has been tested. Freshly prepared analytes and catholyte without the addition of salts were used, as well as stored for 7 months anolytes, prepared with 0.5% NaCl and a combination of 0.5% NaCl and 0.5% Na2CO3. The anolyte prepared with a combination of 0.5% NaCl and 0.5% Na2CO3, as well as the anolyte obtained with 0.5% NaCl, exhibit high antimicrobial activity against the surface microflora of strawberries, cherries, and sour cherries. They inactivate E. coli for 15 minutes. The other species of the fam. Enterobacteriaceae were also affected to the maximum extent, as is the total number of microorganisms, especially in cherries and sour cherries. Even stored for 7 months, they largely retain their antimicrobial properties. Anolyte and catholyte, obtained without the addition of salts, showed a lower effect on the total number of microorganisms, but had a significant effect on Gram-negative bacteria, and especially with regard to the sanitary indicative E. coli.

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