scholarly journals Ruthenium Complexes with 2-Pyridin-2-yl-1H-Benzimidazole as Potential Antimicrobial Agents: Correlation between Chemical Properties and Anti-Biofilm Effects

2021 ◽  
Vol 22 (18) ◽  
pp. 10113
Author(s):  
Agnieszka Jabłońska-Wawrzycka ◽  
Patrycja Rogala ◽  
Grzegorz Czerwonka ◽  
Katarzyna Gałczyńska ◽  
Marcin Drabik ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Ruthenium Complexes ◽  
Chemical Properties ◽  
Oxidation States ◽  
Health Concern ◽  
Ru Complexes ◽  
Initial Binding ◽  
Aggregation Phenomenon ◽  
Better Than ◽  
Urgent Action

Antimicrobial resistance is a growing public health concern that requires urgent action. Biofilm-associated resistance to antimicrobials begins at the attachment phase and increases as the biofilms maturate. Hence, interrupting the initial binding process of bacteria to surfaces is essential to effectively prevent biofilm-associated problems. Herein, we have evaluated the antibacterial and anti-biofilm activities of three ruthenium complexes in different oxidation states with 2-pyridin-2-yl-1H-benzimidazole (L1 = 2,2′-PyBIm): [(η6-p-cymene)RuIIClL1]PF6 (Ru(II) complex), mer-[RuIIICl3(CH3CN)L1]·L1·3H2O (Ru(III) complex), (H2L1)2[RuIIICl4(CH3CN)2]2[RuIVCl4(CH3CN)2]·2Cl·6H2O (Ru(III/IV) complex). The biological activity of the compounds was screened against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa strains. The results indicated that the anti-biofilm activity of the Ru complexes at concentration of 1 mM was better than that of the ligand alone against the P. aeruginosa PAO1. It means that ligand, in combination with ruthenium ion, shows a synergistic effect. The effect of the Ru complexes on cell surface properties was determined by the contact angle and zeta potential values. The electric and physical properties of the microbial surface are useful tools for the examined aggregation phenomenon and disruption of the adhesion. Considering that intermolecular interactions are important and largely define the functions of compounds, we examined interactions in the crystals of the Ru complexes using the Hirshfeld surface analysis.

scholarly journals Ruthenium Complexes in the Fight against Pathogenic Microorganisms. An Extensive Review

Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 874
Author(s):  
Alexandra-Cristina Munteanu ◽  
Valentina Uivarosi
Keyword(s):  
Anticancer Agents ◽  
Cellular Localization ◽  
Antimicrobial Agents ◽  
Chemical Space ◽  
Ruthenium Complexes ◽  
Chemical Properties ◽  
Biological Behavior ◽  
Ros Generation ◽  
Drug Candidates ◽  
Advantages And Disadvantages

The widespread use of antibiotics has resulted in the emergence of drug-resistant populations of microorganisms. Clearly, one can see the need to develop new, more effective, antimicrobial agents that go beyond the explored ‘chemical space’. In this regard, their unique modes of action (e.g., reactive oxygen species (ROS) generation, redox activation, ligand exchange, depletion of substrates involved in vital cellular processes) render metal complexes as promising drug candidates. Several Ru(II/III) complexes have been included in, or are currently undergoing, clinical trials as anticancer agents. Based on the in-depth knowledge of their chemical properties and biological behavior, the interest in developing new ruthenium compounds as antibiotic, antifungal, antiparasitic, or antiviral drugs has risen. This review will discuss the advantages and disadvantages of Ru(II/III) frameworks as antimicrobial agents. Some aspects regarding the relationship between their chemical structure and mechanism of action, cellular localization, and/or metabolism of the ruthenium complexes in bacterial and eukaryotic cells are discussed as well. Regarding the antiviral activity, in light of current events related to the Covid-19 pandemic, the Ru(II/III) compounds used against SARS-CoV-2 (e.g., BOLD-100) are also reviewed herein.

Cu Doped TiO2: Visible Light Assisted Photocatalytic Antimicrobial Activity and High Temperature Anatase Stability

2018 ◽  
Author(s):  
Snehamol Mathew ◽  
Priyanka Ganguly ◽  
Stephen Rhatigan ◽  
Vignesh Kumaravel ◽  
Ciara Byrne ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Density Functional ◽  
Anatase Phase ◽  
Sol Gel ◽  
Chemical Properties ◽  
Light Irradiation ◽  
Health Concern ◽  
Bacterial Inactivation ◽  
X Ray

Indoor surface contamination by microbes is a major public health concern. A damp environment is one potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO<sub>2</sub>) can effectively curb this growing threat.<b> </b>Metal-doped titania in anatase phase has been proved as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu) doped TiO<sub>2 </sub>(Cu-TiO<sub>2</sub>) was evaluated against <i>Escherichia coli</i> (Gram-negative) and <i>Staphylococcus aureus</i> (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO<sub>2 </sub>was carried out <i>via</i> sol-gel technique. Cu-TiO<sub>2</sub> further calcined at various temperatures (in the range of 500 °C – 700 °C) to evaluate the thermal stability of TiO<sub>2</sub> anatase phase. The physico-chemical properties of the samples were characterised through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV-visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO<sub>2</sub> was maintained well, up to 650 °C, by the Cu dopant. UV-DRS results suggested that the visible light absorption property of Cu-TiO<sub>2 </sub>was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasises the introduction of Cu<sup>+</sup> and Cu<sup>2+</sup> ions by replacing Ti<sup>4+</sup> ions in the TiO<sub>2</sub> lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9%) was attained in 30 mins of visible light irradiation by Cu-TiO<sub>2</sub>.

scholarly journals Super-Cationic Peptide Dendrimers—Synthesis and Evaluation as Antimicrobial Agents

Antibiotics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 695
Author(s):  
Estelle J. Ramchuran ◽  
Isabel Pérez-Guillén ◽  
Linda A. Bester ◽  
René Khan ◽  
Fernando Albericio ◽  
...  
Keyword(s):  
Antibacterial Agent ◽  
Antimicrobial Agents ◽  
Health Concern ◽  
Gram Negative Bacteria ◽  
Cationic Peptide ◽  
Public Health Concern ◽  
Gram Negative ◽  
Peptide Dendrimers ◽  
Microbial Infections ◽  
Lead Candidate

Microbial infections are a major public health concern. Antimicrobial peptides (AMPs) have been demonstrated to be a plausible alternative to the current arsenal of drugs that has become inefficient due to multidrug resistance. Herein we describe a new AMP family, namely the super-cationic peptide dendrimers (SCPDs). Although all members of the series exert some antibacterial activity, we propose that special attention should be given to (KLK)2KLLKLL-NH2 (G1KLK-L2KL2), which shows selectivity for Gram-negative bacteria and virtually no cytotoxicity in HepG2 and HEK293. These results reinforce the validity of the SCPD family as a valuable class of AMP and support G1KLK-L2KL2 as a strong lead candidate for the future development of an antibacterial agent against Gram-negative bacteria.

scholarly journals Insights in Behavior of Variably Formulated Alginate-Based Microcapsules for Cell Transplantation

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Pia Montanucci ◽  
Silvia Terenzi ◽  
Claudio Santi ◽  
Ilaria Pennoni ◽  
Vittorio Bini ◽  
...  
Keyword(s):  
Divalent Cations ◽  
Chemical Properties ◽  
Live Cells ◽  
High Performing ◽  
Physical Chemical ◽  
Degenerative Disorders ◽  
Selection Of ◽  
Better Than

Alginate-based microencapsulation of live cells may offer the opportunity to treat chronic and degenerative disorders. So far, a thorough assessment of physical-chemical behavior of alginate-based microbeads remains cloudy. A disputed issue is which divalent cation to choose for a high performing alginate gelling process. Having selected, in our system, high mannuronic (M) enriched alginates, we studied different gelling cations and their combinations to determine their eventual influence on physical-chemical properties of the final microcapsules preparation,in vitroandin vivo. We have shown that used of ultrapure alginate allows for high biocompatibility of the formed microcapsules, regardless of gelation agents, while use of different gelling cations is associated with corresponding variable effects on the capsules’ basic architecture, as originally reported in this work. However, only the final application which the capsules are destined to will ultimately guide the selection of the ideal, specific gelling divalent cations, since in principle there are no capsules that are better than others.

Structural and chemical properties of half-sandwich rhodium complexes supported by the bis(2-pyridyl)methane ligand

2019 ◽  
Vol 48 (33) ◽  
pp. 12396-12406 ◽  
Author(s):  
Davide Lionetti ◽  
Victor W. Day ◽  
James D. Blakemore
Keyword(s):  
Chemical Properties ◽  
Oxidation States ◽  
Rhodium Complexes ◽  
Half Sandwich ◽  
And Chemical Properties

The bis(2-pyridyl)methane ligand can support [Cp*Rh] complexes (Cp* = pentamethylcyclopentadienyl) in the Rh(iii) and Rh(ii) oxidation states. Structural and reactivity studies demonstrate significant differences between these complexes and notable analogues bearing the related dimethylbis(2-pyridyl)methane ligand.

scholarly journals Streptococcus salivarius inhibits immune activation by periodontal disease pathogens

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kyle W. MacDonald ◽  
Ryan M. Chanyi ◽  
Jean M. Macklaim ◽  
Peter A. Cadieux ◽  
Gregor Reid ◽  
...  
Keyword(s):  
Periodontal Disease ◽  
Immune Activation ◽  
Antimicrobial Agents ◽  
Fusobacterium Nucleatum ◽  
Health Concern ◽  
Chewing Gum ◽  
Gingival Fibroblasts ◽  
Streptococcus Salivarius ◽  
Periodontal Pathogens ◽  
Whole Cell Lysate

Abstract Background Periodontal disease represents a major health concern. The administration of beneficial microbes has been increasing in popularity over efforts to manipulate the microbes using antimicrobial agents. This study determined the ability of Streptococcus salivarius to inhibit IL-6 and IL-8 production by gingival fibroblasts when activated by periodontal pathogens and their effect on the salivary microbiome. Methods Primary human gingival fibroblasts were challenged with Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum and a combination of all three. IL-6 and IL-8 cytokine release were measured. Using this same model, S. salivarius K12, M18 and different supernatant and whole-cell lysate fractions of S. salivarius K12 were administered to pathogen-induced fibroblasts. A patient study of healthy participants was also conducted to determine the effect S. salivarius K12 had on the native microbiome using 16S next generation sequence analysis. Results All pathogens tested induced a significant IL-6 and IL-8 response. S. salivarius K12 or M18, did not exhibit an increase in inflammatory cytokines. When either of the probiotic strains were co-administered with a pathogen, there were significant reductions in both IL-6 and IL-8 release. This effect was also observed when gingival fibroblasts were pre-treated with either S. salivarius K12 or M18 and then stimulated with the oral pathogens. Chewing gum containing S. salivarius K12 did not alter the salivary microbiome and did not increase inflammatory markers in the oral cavity. Conclusion S. salivarius K12 and M18 prevented immune activation induced by periodontal disease pathogens. S. salivarius K12 did not alter the salivary microbiome or induce immune activation when administered as a chewing gum. These results warrant further study to determine if it may be an effective treatment in a model of periodontal disease.

scholarly journals Loxosceles gaucho Spider Venom: An Untapped Source of Antimicrobial Agents

Toxins ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 522 ◽  
Author(s):  
Paula Segura-Ramírez ◽  
Pedro Silva Júnior
Keyword(s):  
Bacterial Infections ◽  
High Performance ◽  
Antimicrobial Agents ◽  
Chemical Properties ◽  
Carcinoma Cells ◽  
Promising Candidate ◽  
Human Red Blood Cells ◽  
New Antibiotics ◽  
Conventional Antibiotics ◽  
Human Cervical Carcinoma Cells

The remarkable ability of microorganisms to develop resistance to conventional antibiotics is one of the biggest challenges that the pharmaceutical industry currently faces. Recent studies suggest that antimicrobial peptides discovered in spider venoms may be useful resources for the design of structurally new anti-infective agents effective against drug-resistant microorganisms. In this work, we found an anionic antibacterial peptide named U1-SCRTX-Lg1a in the venom of the spider Loxosceles gaucho. The peptide was purified using high-performance liquid chromatography (HPLC), its antimicrobial activity was tested through liquid growth inhibition assays, and its chemical properties were characterized using mass spectrometry. U1-SCRTX-Lg1a was found to show a monoisotopic mass of 1695.75 Da, activity against Gram-negative bacteria, a lack of hemolytic effects against human red blood cells, and a lack of cytotoxicity against human cervical carcinoma cells (HeLa). Besides this, the sequence of the peptide exhibited great similarity to specific regions of phospholipases D from different species of Loxosceles spiders, leading to the hypothesis that U1-SCRTX-Lg1a may have originated from a limited proteolytic cleavage. Our data suggest that U1-SCRTX-Lg1a is a promising candidate for the development of new antibiotics that could help fight bacterial infections and represents an exciting discovery for Loxosceles spiders.

A COMPARISON OF VARIOUS MEANS OF MEASURING THE DEGREE OF DECOMPOSITION OF VIRGIN PEAT MATERIALS IN THE CONTEXT OF THEIR RELATIVE BIODEGRADABILITY

1979 ◽  
Vol 59 (4) ◽  
pp. 397-400 ◽  
Author(s):  
M. P. LÉVESQUE ◽  
S. P. MATHUR
Keyword(s):  
Chemical Properties ◽  
Fiber Content ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
Better Than ◽  
And Chemical Properties

Eleven physical and chemical properties of 26 peat materials from a total of five virgin profiles were determined and statistically analyzed for correlations among attributes that relate to the degree of decomposition, and with the rates at which the materials biodegraded. Estimation of fiber content made routinely by pedologists in the field correlated with relative, biodegradability better than any other criterion of decomposition and humification.

scholarly journals Salmonella Heidelberg Strain Responses to Essential Oil Components

2015 ◽  
Vol 4 (5) ◽  
pp. 73 ◽  
Author(s):  
Juliany Rivera Calo ◽  
Christopher A. Baker ◽  
Si Hong Park ◽  
Steven C. Ricke
Keyword(s):  
Foodborne Pathogens ◽  
Food Production ◽  
Antimicrobial Agents ◽  
Health Concern ◽  
Orange Oil ◽  
Major Health ◽  
Minimal Inhibitory Concentrations ◽  
Color Changes ◽  
Different Sources ◽  
Strain Responses

<em>Salmonella</em> are one of the more prominent foodborne pathogens that represent a major health risk to humans. <em>Salmonella </em>serovar Heidelberg strains are increasingly becoming an important public health concern, since they have been identified as one of the primary <em>Salmonella </em>serovars responsible for human outbreaks. Over the years, <em>Salmonella </em>Heidelberg isolates have exhibited higher rates of resistance to multiple antimicrobial agents compared to other <em>Salmonella </em>serovars. Essential oils (EOs) have been widely used as alternatives to chemical-based antimicrobials. In the current research, five EOs were screened to determine their antimicrobial activity against 15 <em>S. </em>Heidelberg strains from different sources. Oils tested were R(+)-limonene, orange terpenes, cold compressed orange oil, trans-cinnamaldehyde and carvacrol. EOs were stabilized in nutrient broth by adding 0.15% (w/v) agar. Tube dilution assays and minimal inhibitory concentrations (MIC) were determined by observing color changes in samples during exposure to EOs. Carvacrol and <em>trans-</em>cinnamaldehyde completely inhibited the growth of <em>S.</em> Heidelberg strains, while R(+)-limonene and orange terpenes did not show any inhibitory activity against the strains tested. Cold compressed orange oil only inhibited growth of two of the strains exhibiting an MIC of 1%. All <em>S</em>. Heidelberg isolates evaluated exhibited similar responses to the respective EOs. The use of all natural antimicrobials such as specific EOs offers the potential to limit the majority of <em>S. </em>Heidelberg isolates that may occur in food production.

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