scholarly journals Synthesis of modified pyridine and bipyridine substituted coumarins as potent antimicrobial agents

2015 ◽  
Vol 80 (6) ◽  
pp. 739-747 ◽  
Author(s):  
Hemali Lad ◽  
Rakesh Giri ◽  
Yogita Chovatiya ◽  
Dinkar Brahmbhatt
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Antimicrobial Agents ◽  
Molecular Hybridization ◽  
Dilution Method ◽  
Gram Negative ◽  
Comparable Activity ◽  
Broth Dilution ◽  
Substituted Coumarins

In search for new antimicrobial agents a series of new modified pyridine and bipyridine substituted coumarins 5a-y was designed and synthesized by adopting molecular hybridization strategy. All the synthesized compounds were evaluated for their in vitro antimicrobial activity using broth dilution method against selected bacterial (Gram-positive and Gram-negative) and fungal strains. Compounds 5a, 5f, 5g, 5n, 5r, 5t, 5w, 5x and 5y demonstrated promising antibacterial activity while other derivatives showed comparable activity to standard drugs used as reference.

scholarly journals Synthesis and Biological Activity of 1,2,4-Triazolo-[3,4-b]Thiadiazole as Antimicrobial Agents

2014 ◽  
Vol 26 ◽  
pp. 45-52
Author(s):  
Piyush B. Vekariya ◽  
Jalpa R. Pandya ◽  
Vaishali Goswami ◽  
Hitendra S. Joshi
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Spectral Analysis ◽  
Biological Activity ◽  
Antimicrobial Agents ◽  
Dilution Method ◽  
Mass Spectral Analysis ◽  
Mass Spectral ◽  
Broth Dilution

Some novel 6-fluoro chroman derivatives having 1,2,4-triazolo-[3,4-b]thiadiazole were synthesized and characterized by IR, NMR and mass spectral analysis. All synthesized compounds were screened for antimicrobial activity using broth dilution method. All the compounds showed good antimicrobial activity and compound 5e showed significant antibacterial activity.

scholarly journals Antimicrobial Effect of Malaysian Honey on Some Human Pathogens: an in vitro Study

2020 ◽  
Vol 9 (2) ◽  
Author(s):  
Hassanain AT ◽  
Alyaa AK ◽  
Karim AJ
Keyword(s):  
Antimicrobial Activity ◽  
In Vitro Study ◽  
Antimicrobial Effect ◽  
Dilution Method ◽  
Human Pathogens ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Broth Dilution

Introduction: Honey has potent bactericidal activity against many pathogenic organisms, including various Gram-negative and Gram-positive bacteria. This study aimed to determine the antimicrobial effect of Malaysian honey against different species of human pathogens using optimized honey broth media. Materials and Methods: The antimicrobial activity of honey against standard strains of Gram-negative and Grampositive bacteria and yeast was tested in vitro by the broth dilution method using 10%-100% w/v concentrations prepared in tryptic soy broth. Results: Streptococcus pyogenes was the most sensitive pathogen, it was completely inhibited by 30% honey broth medium. The most resistant were E. faecalis, S. aureus and MRSA, but they were all completely inhibited by 80% honey broth medium. Conclusion: Honey is shown to possess antimicrobial activity against human Gram-positive and negative medically important bacteria.

scholarly journals In VitroAntibacterial Activity of Essential Oils againstStreptococcus pyogenes

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Julien Sfeir ◽  
Corinne Lefrançois ◽  
Dominique Baudoux ◽  
Séverine Derbré ◽  
Patricia Licznar
Keyword(s):  
Antibacterial Activity ◽  
Essential Oils ◽  
Antimicrobial Agents ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Thymus Vulgaris ◽  
Dilution Method ◽  
Origanum Compactum ◽  
Broth Dilution

Streptococcus pyogenesplays an important role in the pathogenesis of tonsillitis. The present study was conducted to evaluate thein vitroantibacterial activities of 18 essential oils chemotypes from aromatic medicinal plants againstS. pyogenes. Antibacterial activity of essential oils was investigated using disc diffusion method. Minimum Inhibitory Concentration of essential oils showing an important antibacterial activity was measured using broth dilution method. Out of 18 essential oils tested, 14 showed antibacterial activity againstS. pyogenes. Among themCinnamomum verum, Cymbopogon citratus, Thymus vulgaris CT thymol, Origanum compactum, andSatureja montanaessential oils exhibited significant antibacterial activity. Thein vitroresults reported here suggest that, for patients suffering from bacterial throat infections, if aromatherapy is used, these essential oils, considered as potential antimicrobial agents, should be preferred.

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

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.

scholarly journals An In Vitro Study on the Antimicrobial Properties of Essential Oil Modified Resin Composite against Oral Pathogens

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4383
Author(s):  
Barbara Lapinska ◽  
Aleksandra Szram ◽  
Beata Zarzycka ◽  
Janina Grzegorczyk ◽  
Louis Hardan ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Antifungal Activity ◽  
Antimicrobial Agents ◽  
Resin Composite ◽  
Antimicrobial Properties ◽  
In Vitro Study ◽  
Diffusion Method ◽  
Oral Pathogens

Modifying the composition of dental restorative materials with antimicrobial agents might induce their antibacterial potential against cariogenic bacteria, e.g., S.mutans and L.acidophilus, as well as antifungal effect on C.albicans that are major oral pathogens. Essential oils (EOs) are widely known for antimicrobial activity and are successfully used in dental industry. The study aimed at evaluating antibacterial and antifungal activity of EOs and composite resin material (CR) modified with EO against oral pathogens. Ten EOs (i.e., anise, cinnamon, citronella, clove, geranium, lavender, limette, mint, rosemary thyme) were tested using agar diffusion method. Cinnamon and thyme EOs showed significantly highest antibacterial activity against S.mutans and L.acidophilus among all tested EOs. Anise and limette EOs showed no antibacterial activity against S.mutans. All tested EOs exhibited antifungal activity against C.albicans, whereas cinnamon EO showed significantly highest and limette EO significantly lowest activity. Next, 1, 2 or 5 µL of cinnamon EO was introduced into 2 g of CR and microbiologically tested. The modified CR showed higher antimicrobial activity in comparison to unmodified one. CR containing 2 µL of EO showed the best antimicrobial properties against S.mutans and C.albicans, while CR modified with 1 µL of EO showed the best antimicrobial properties against L.acidophilus.

scholarly journals Investigating In Vitro Antibacterial Activities of Medicinal Plants Having Folkloric Repute in Ethiopian Traditional Medicine

2019 ◽  
Vol 24 ◽  
pp. 2515690X1988627 ◽  
Author(s):  
Mekonnen Sisay ◽  
Negussie Bussa ◽  
Tigist Gashaw ◽  
Getnet Mengistu
Keyword(s):  
Antibacterial Activity ◽  
Medicinal Plants ◽  
Antimicrobial Agents ◽  
Bacterial Isolates ◽  
Zone Of Inhibition ◽  
Traditional Use ◽  
Gram Negative ◽  
E Coli ◽  
Slow Development

Medicinal plants are targeted in the search for new antimicrobial agents. Nowadays, there is an alarmingly increasing antimicrobial resistance to available agents with a very slow development of new antimicrobials. It is, therefore, necessary to extensively search for new agents based on the traditional use of herbal medicines as potential source. The antibacterial activity of 80% methanol extracts of the leaves of Verbena officinalis (Vo-80ME), Myrtus communis (Mc-80ME), and Melilotus elegans (Me-80ME) was tested against 6 bacterial isolates using agar well diffusion technique. In each extract, 3 concentrations of 10, 20, and 40 mg/well were tested for each bacterium. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also determined. Vo-80ME and Mc-80ME exhibited promising antibacterial activity against Staphylococcus aureus with the highest zone of inhibition being 18.67 and 26.16 mm, respectively at concentration of 40 mg/well. Regarding gram-negative bacteria, Vo-80ME exhibited an appreciable activity against Escherichia coli and Salmonella typhi. Mc-80ME displayed remarkable activity against all isolates including Pseudomonas aeruginosa with the maximum zone of inhibition being 22.83 mm. Me-80ME exhibited better antibacterial activity against E coli, but its secondary metabolites had little or no activity against other gram-negative isolates. The MIC values of Vo-80ME ranged from 0.16 to 4.00 mg/mL. The lowest MIC was observed in Mc-80ME, with the value being 0.032 mg/mL. Mc-80ME had bactericidal activity against all tested bacterial isolates. Mc-80ME showed remarkable zone of inhibitions in all tested bacterial isolates. Besides, Vo-80ME showed good antibacterial activity against S aureus, E coli, and S typhi. Conversely, Me-80ME has shown good activity against E coli only. Generally, M communis L and V officinalis have good MIC and MBC results.

scholarly journals SPS-neutralization in tissue samples for efficacy testing of antimicrobial peptides

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Gabrielle Sherella Dijksteel ◽  
Peter H. Nibbering ◽  
Magda M. W. Ulrich ◽  
Esther Middelkoop ◽  
Bouke K. H. L. Boekema
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Peptides ◽  
Antimicrobial Agents ◽  
Ex Vivo ◽  
Residual Activity ◽  
Gram Negative Bacteria ◽  
Tissue Samples ◽  
Gram Negative ◽  
Viable Bacteria

Abstract Background Accurate determination of the efficacy of antimicrobial agents requires neutralization of residual antimicrobial activity in the samples before microbiological assessment of the number of surviving bacteria. Sodium polyanethol sulfonate (SPS) is a known neutralizer for the antimicrobial activity of aminoglycosides and polymyxins. In this study, we evaluated the ability of SPS to neutralize residual antimicrobial activity of antimicrobial peptides [SAAP-148 and pexiganan; 1% (wt/v) in PBS], antibiotics [mupirocin (Bactroban) and fusidic acid (Fucidin) in ointments; 2% (wt/wt))] and disinfectants [2% (wt/wt) silver sulfadiazine cream (SSD) and 0.5% (v/v) chlorhexidine in 70% alcohol]. Methods Homogenates of human skin models that had been exposed to various antimicrobial agents for 1 h were pipetted on top of Methicillin-resistant Staphylococcus aureus (MRSA) on agar plates to determine whether the antimicrobial agents display residual activity. To determine the optimal concentration of SPS for neutralization, antimicrobial agents were mixed with PBS or increasing doses of SPS in PBS (0.05–1% wt/v) and then 105 colony forming units (CFU)/mL MRSA were added. After 30 min incubation, the number of viable bacteria was assessed. Next, the in vitro efficacy of SAAP-148 against various gram-positive and gram-negative bacteria was determined using PBS or 0.05% (wt/v) SPS immediately after 30 min incubation of the mixture. Additionally, ex vivo excision wound models were inoculated with 105 CFU MRSA for 1 h and exposed to SAAP-148, pexiganan, chlorhexidine or PBS for 1 h. Subsequently, samples were homogenized in PBS or 0.05% (wt/v) SPS and the number of viable bacteria was assessed. Results All tested antimicrobials displayed residual activity in tissue samples, resulting in a lower recovery of surviving bacteria on agar. SPS concentrations at ≥0.05% (wt/v) were able to neutralize the antimicrobial activity of SAAP-148, pexiganan and chlorhexidine, but not of SSD, Bactroban and Fucidin. Finally, SPS-neutralization in in vitro and ex vivo efficacy tests of SAAP-148, pexiganan and chlorhexidine against gram-positive and gram-negative bacteria resulted in significantly higher numbers of CFU compared to control samples without SPS-neutralization. Conclusions SPS was successfully used to neutralize residual activity of SAAP-148, pexiganan and chlorhexidine and this prevented an overestimation of their efficacy.

scholarly journals Аntibacterial inorganic agents: efficiency of using multicomponent systems

2020 ◽  
Vol 10 (4) ◽  
pp. 639-654
Author(s):  
А. A. Meleshko ◽  
A. G. Afinogenova ◽  
G. E. Afinogenov ◽  
A. A. Spiridonova ◽  
V. P. Tolstoy
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Antimicrobial Agents ◽  
Metal Oxide Nanoparticles ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Nanoscale Systems ◽  
Gram Negative ◽  
Low Toxicity

Metal and metal oxide nanoparticles (NPs) are promising antibacterial agents. They have a broad antimicrobial activity against both Gram-positive and Gram-negative bacteria, viruses, and protozoans. The use of NPs reduces the possibility of the microbial resistance development. This review briefly shows the general mechanisms and the main factors of antibacterial activity of NPs. In this article, a comprehensive review of the recent researches in the field of new antimicrobial agents with superior long-term bactericidal activity and low toxicity is provided. The review gives the examples of synthesis of double and triple nanocomposites based on following oxides: CuO, ZnO, Fe3O4, Ag2O, MnO2, etc. including metal and nonmetal doped nanocomposites (for example with Ag, Ce, Cr, Mn, Nd, Co, Sn, Fe, N, F, etc.). Compared with bactericidal action of individual oxides, the nanocomposites demonstrate superior antibacterial activity and have synergistic effects. For example, the antimicrobial activity of ZnO against both Gram-positive and Gram-negative bacteria was increased by -100% by formation of triple nanocomposites ZnO—MnO2—Cu2O or ZnO—Ag2O—Ag2S. Similar effect was showed for Ce-doped ZnO and Zn-doped CuO. The present article also provides the examples of nanocomposites containing NPs and organic (chitosan, cellulose, polyvinylpyrrolidone, biopolymers, etc.) or inorganic materials with special structure (graphene oxide, TiO2 nanotubes, silica) which demonstrate controlled release and longterm antibacterial activity. All of the considered nanocomposites and their combinations have a pronounced long-term antimicrobial effect including against antibiotic-resistant strains. They are able to prevent the formation of microbial biofilms on biotic and abiotic surfaces, have low toxicity to eukaryotic cells, demonstrate anti-inflammatory and woundhealing properties in compositions with polymers (sodium alginate, collagen, polyvinylpyrrolidone, etc.). The use of nanoscale systems can solve several important practical problems at the same time: saving of long-term antimicrobial activities while reducing the number of compounds, creation of new antimicrobial agents with low toxicity and reduced environmental impact, development of new biocidal materials, including new coatings for effective antimicrobial protection of medical devices.

scholarly journals Manganese (II) and Cobalt (II) Acetylacetonates as Antimicrobial Agents

2019 ◽  
Vol 1 ◽  
pp. 176-185
Author(s):  
S G Yiase ◽  
S O Adejo ◽  
S T Iningev
Keyword(s):  
Antimicrobial Activity ◽  
Antifungal Activity ◽  
Antimicrobial Agents ◽  
Inhibitory Concentration ◽  
Dilution Method ◽  
Spectroscopic Techniques ◽  
Metal Chlorides ◽  
Activity Screening ◽  
Antibacterial And Antifungal ◽  
Broth Dilution

Mn(II) and Co(II) complexes were prepared by reaction of the metal chlorides with acetylacetone in ammonical aqueous medium. The metal complexes were prepared in order to investigate their antimicrobial activity on some selected pathogens. The characterisation of the complexes was on the basis of various spectroscopic techniques like infrared and ultraviolet studies. The compounds were subjected to antimicrobial activity screening using serial broth dilution method. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal/Fungicidal Concentration (MBC/MFC) were determined. Mn(II) complex has shown significantly both antibacterial and antifungal activity with a MIC of 1.25 μg/mL while Co(II) complex was noticeable for antifungal activity at the same concentration. Whereas Mn(II) acetylacetonate is a more potent bactericide while Co(II) acetylacetonate is a more potent fungicide, both with MBC/MFC value of 2.5 μg/mL. Antimicrobial agent of the ligand has enhanced on complexation with Mn(II) and Co(II) ions. Though, the potency of the prepared antibiotics on the tested microbes is less compared to the standard drugs (Ciprofloxacin and Fulcin).

Catalyst Free and Energy Economical Synthesis of Thiazole Derivatives Bearing Azo Imine Linkage with Imidazole as Antimicrobial Agents

2019 ◽  
Vol 16 (3) ◽  
pp. 284-290
Author(s):  
Nayan M. Panchani ◽  
Hitendra S. Joshi
Keyword(s):  
Antibacterial Activity ◽  
Room Temperature ◽  
Antimicrobial Agents ◽  
Fungal Infections ◽  
Gram Negative Bacteria ◽  
Thiazole Derivatives ◽  
Microbial Diseases ◽  
Gram Negative ◽  
In Vitro Antibacterial Activity

Background:Several strategies have been reported for the synthesis of thiazole derivatives.Methods:However, many of these methods suffer from several drawbacks. Several modifications have been made to counter these problems. Here, we have synthesized a new series of 2-(2-((1HImidazol- 4-yl)methylene)hydrazinyl)-4-(4-substitutedphenyl)thiazoles without using the catalyst at room temperature.Results:The structures of synthesized compounds have been confirmed by spectral analysis, such as Mass, IR, 1H NMR and 13C NMR. All synthesized compounds were screened for in vitro antibacterial activity against some gram-positive and gram-negative bacteria.Conclusion:The thiazole derivatives, with a pharmacologically potent group, discussed in this article may provide valued therapeutic important in the treatment of microbial diseases, especially against bacterial and fungal infections.

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