scholarly journals Design, Synthesis and in vitro Antibacterial Evaluation of Naphthalen-2-yloxy based Oxadiazole-2-thione Derivatives

2021 ◽  
Vol 33 (2) ◽  
pp. 266-270
Author(s):  
VIVEK KUMAR ◽  
RAJNISH KUMAR ◽  
SALAHUDDIN ◽  
AVIJIT MAZUMDER
Keyword(s):  
Antibacterial Activity ◽  
Bacillus Pumilus ◽  
Mannich Bases ◽  
Shigella Dysenteriae ◽  
Secondary Amines ◽  
Significant Activity ◽  
Bacterial Strains ◽  
Vibrio Cholera ◽  
Standard Drug

A series of novel Mannich bases 5-(naphthalen-2-yloxymethyl)-3-(substituted)aminomethyl-3H-[1,3,4]oxadiazole-2-thiones (5a-h) were synthesized by aminomethylation of substituted-1,3,4-oxadiazole-2(3H)-thione by equimolar concentration of primary or secondary amines. Synthesized compounds were characterized by spectrometric techniques (IR, 1H & 13C NMR), and evaluated for antibacterial potential against various Gram-positive and Gram-negative bacterial strains using cup-plate method employing ciprofloxacin as standard drug. Compounds 5a-c and 5g exhibited strong antibacterial activity against tested bacterial strains. Compound 5a was active against Bacillus pumilus, Shigella dysenteriae and Vibrio cholera; compound 5b exhibited significant activity against Bacillus pumilus, and Shigella dysenteriae; compound 5c was active against Bacillus pumilus and Vibrio cholera and compound 5g was active against Dshigella boydii and Acinetobacter aceti bacterial strains. The SAR study revealed that the synthesized compounds (5a-h) having less bulky group exhibited good antibacterial activity.

scholarly journals In-Vitro Antibacterial Activity of Endophytic Fungi from Peganum harmala (Laghouat, Algeria)

2020 ◽  
Vol 10 (3-s) ◽  
pp. 47-51
Author(s):  
Yasmina Ouzid ◽  
Siliya Karaoui ◽  
Noria Smail Saadoun ◽  
Karim Houali
Keyword(s):  
Antibacterial Activity ◽  
Secondary Metabolites ◽  
Endophytic Fungi ◽  
Biological Activities ◽  
Significant Activity ◽  
Bacterial Strains ◽  
Peganum Harmala ◽  
Bioactive Substances ◽  
Significant Difference

Medicinal plants are an inexhaustible source of molecules. They are colonized by mycoendophytes, fungi living in their tissues without apparent symptoms. These fungi can provide secondary metabolites with biological activities. It is with this in mind that we are interested in a spontaneous plant from the dayas region (Laghouat, Algeria): Peganum harmala or Harmel, a toxic medicinal plant belonging to the family Zygophyllaceae. Our study consists in highlighting the antibacterial activity of four kinds of mycoendophytes: Cladosporium, Alternaria, Aspergillus and Penicillium isolated from the leaves of this plant. The antibacterial activity is evaluated by the technique of the double disk diffusion on agar with respect to some Gram-positive bacterial strains. We have adopted two protocols for this purpose. For the first, the mycelia of all the mushrooms are deposited in the same petri dish. For the second, a single disc of the mycelium of a single species is deposited per box. The results obtained show a difference in the sensitivity of the bacterial strains to the bioactive substances of the mycoendophytes studied. The Alternaria genus showed the most significant activity. ANOVA performed between the mean diameters of the mycoendophyte inhibition zones and the antibiotic test disc: Chloramphenicol showed a highly significant difference between these two measurements. The Newman-Keuls test revealed a difference in the susceptibility of bacterial strains to the secondary metabolites of fungus mycoendophytes of Peganum harmala according to the two protocols used. The antibacterial effect is related to interactions between endophytic fungi and their host plant.

Synthesis, Molecular Modelling and Antibacterial Activity Against Helicobacter pylori of Novel Diflunisal Derivatives as Urease Enzyme Inhibitors

2019 ◽  
Vol 16 (4) ◽  
pp. 392-400 ◽  
Author(s):  
Göknil Pelin Coşkun ◽  
Teodora Djikic ◽  
Sadık Kalaycı ◽  
Kemal Yelekçi ◽  
Fikrettin Şahin ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Antibacterial Activity ◽  
Enzyme Inhibitors ◽  
Binding Modes ◽  
Bacterial Strains ◽  
Urease Enzyme ◽  
H Pylori ◽  
Ulcer Treatment ◽  
Main Factor

Background:The main factor for the prolongation of the ulcer treatment in the gastrointestinal system would be Helicobacter pylori infection, which can possibly lead to gastrointestinal cancer. Triple therapy is the treatment of choice by today's standards. However, observed resistance among the bacterial strains can make the situation even worse. Therefore, there is a need to discover new targeted antibacterial therapy in order to make success in the eradication of H. pylori infections.Methods:The targeted therapy rule is to identify the related macromolecules that are responsible for the survival of the bacteria. Thus, 2-[(2',4'-difluoro-4-hydroxybiphenyl-3-yl)carbonyl]-N- (substituted)hydrazinocarbothioamide (3-13) and 5-(2',4'-difluoro-4-hydroxybiphenyl-3-yl)-4- (substituted)-2,4-dihydro-3H-1,2,4-triazole-3-thiones (14-17) were synthesized and evaluated for antibacterial activity in vitro against H. pylori.Results:All of the tested compounds showed remarkable antibacterial activity compared to the standard drugs (Ornidazole, Metronidazole, Nitrimidazin and Clarithromycin). Compounds 4 and 13 showed activity as 2µg/ml MIC value.Conclusion:In addition, we have investigated binding modes and energy of the compounds 4 and 13 on urease enzyme active by using the molecular docking tools.

scholarly journals Effect of Gold Nanoparticles and Silicon on the Bioactivity and Antibacterial Properties of Hydroxyapatite/Chitosan/Tricalcium Phosphate-Based Biomicroconcretes

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3854
Author(s):  
Joanna Czechowska ◽  
Ewelina Cichoń ◽  
Anna Belcarz ◽  
Anna Ślósarczyk ◽  
Aneta Zima
Keyword(s):  
Gold Nanoparticles ◽  
Antibacterial Activity ◽  
Tricalcium Phosphate ◽  
Setting Time ◽  
Antibacterial Properties ◽  
Bone Substitutes ◽  
Bacterial Strains ◽  
Setting Times ◽  
Biological Studies

Bioactive, chemically bonded bone substitutes with antibacterial properties are highly recommended for medical applications. In this study, biomicroconcretes, composed of silicon modified (Si-αTCP) or non-modified α-tricalcium phosphate (αTCP), as well as hybrid hydroxyapatite/chitosan granules non-modified and modified with gold nanoparticles (AuNPs), were designed. The developed biomicroconcretes were supposed to combine the dual functions of antibacterial activity and bone defect repair. The chemical and phase composition, microstructure, setting times, mechanical strength, and in vitro bioactive potential of the composites were examined. Furthermore, on the basis of the American Association of Textile Chemists and Colorists test (AATCC 100), adapted for chemically bonded materials, the antibacterial activity of the biomicroconcretes against S. epidermidis, E. coli, and S. aureus was evaluated. All biomicroconcretes were surgically handy and revealed good adhesion between the hybrid granules and calcium phosphate-based matrix. Furthermore, they possessed acceptable setting times and mechanical properties. It has been stated that materials containing AuNPs set faster and possess a slightly higher compressive strength (3.4 ± 0.7 MPa). The modification of αTCP with silicon led to a favorable decrease of the final setting time to 10 min. Furthermore, it has been shown that materials modified with AuNPs and silicon possessed an enhanced bioactivity. The antibacterial properties of all of the developed biomicroconcretes against the tested bacterial strains due to the presence of both chitosan and Au were confirmed. The material modified simultaneously with AuNPs and silicon seems to be the most promising candidate for further biological studies.

scholarly journals ANTIBACTERIAL AND ANTIOXIDANT ACTIVITIES OF STEM BARK ESSENTIAL OIL CONSTITUENTS OF LITSEA GLUTINOSA C. B. ROB.

2016 ◽  
Vol 8 (12) ◽  
pp. 258
Author(s):  
Arunodaya H. S. ◽  
Krishna V. ◽  
Shashikumar R. ◽  
Girish Kumar K.
Keyword(s):  
Antibacterial Activity ◽  
Chemical Composition ◽  
Essential Oil ◽  
Stem Bark ◽  
Diffusion Method ◽  
Vibrio Cholera ◽  
Litsea Glutinosa ◽  
Β Carotene ◽  
Mic Value

<p><strong>Objective: </strong>To evaluate the chemical composition, antibacterial and antioxidant properties of stem bark essential oil of <em>Litsea glutinosa </em>C. B. Rob.</p><p><strong>Methods: </strong>The essential oil isolated from stem bark of <em>L. glutinosa </em>and their chemical composition was analyzed by gas chromatography coupled with mass spectrometry detector. The <em>in vitro </em>antibacterial activity of the stem bark essential oil was investigated against eight human pathogenic bacterial clinical isolates using agar disc diffusion method and MIC value was determined by modified resazurin microtitre-plate assay. The antioxidant activity of essential oil was measured by 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH), 2, 2-azinobis-3-ethylbenzothiazoline-6-sulphonate radical cation (ABTS) and β-carotene bleaching assay.</p><p><strong>Results: </strong>GC-MS analysis of stem bark essential oil resulted in the identification of 37 compounds, off which 9,12-octadecadienoic acid (62.57%), hexadecanoic acid (12.68%), stigmast-5-en-3-ol (6.87%) and vitamin E (2.51%) were the main constituents representing 84.63% of the oil. The determination of <em>in vitro</em> antibacterial activity of stem bark essential oil resulted in significant inhibition zone (15.00±0.57 mm) and MIC value (0.15±0.15×10<sup>-2</sup> mg/ml) against the pathogenic bacteria <em>Vibrio cholera</em> followed by <em>Pseudomonas aeruginosa</em> and <em>Salmonella typhi. </em>The results of DPPH radical scavenging (IC<sub>50</sub>:4.540±0.06 µg/ml), ABTS (IC<sub>50</sub>:256.02±0.06 µg/ml) and β-carotene bleaching assay (%I: 78.51±0.42 <strong>%</strong>) showed significant <em>in vitro</em> antioxidant property.</p><p><strong>Conclusion: </strong><em>L. glutinosa</em> stem bark essential oil showed potential antibacterial activity against the <em>Vibrio cholera</em>. The results of this investigation supported the ethnomedical claim of essential oil as a demulcent, antidiarrheal and antioxidant drug.</p>

scholarly journals A new group of compounds derived from 4-, 5-, 6- and 7-aminoindoles with antimicrobial activity

2018 ◽  
Vol 4 (3) ◽  
pp. 27-36 ◽  
Author(s):  
Irina Stepanenko ◽  
Semen Yamashkin ◽  
Yuliya Kostina ◽  
Alyona Batarsheva ◽  
Mikhail Mironov
Keyword(s):  
Antimicrobial Activity ◽  
Antibacterial Activity ◽  
Antibiotic Resistance ◽  
Biologically Active ◽  
Diffusion Method ◽  
Significant Activity ◽  
Clinical Strains ◽  
Causative Agents ◽  
New Compounds

Introduction. The problem of antibiotic resistance of microorganisms is becoming more urgent in the twenty-first century. Microorganisms possess an evolutionary adaptive capacity. Non-adherence to the basic principles of rational antibiotic therapy leads to menacing consequences. More and more pathogenic microbes are becoming resistant to two or more antibiotics. The search for new compounds with antimicrobial activity is one of the principles for overcoming the antibiotic resistance of microorganisms. Materials and methods. Eighteen test-strains of microorganisms and more than 2000 clinical strains of microorganisms, representating the families Micrococcaceae, Streptococcaceae, Enterobacteriaceae, Moraxellaceae, Pseudomonadaceae, Sphingomonadaceae, Xanthomonadaceae were studied for sensitivity to the compounds derived from 4-, 5-, 6- and 7-aminoindoles. A method of serial dilutions to determine the minimal inhibitory concentration (MIC) of the compounds under study was used in the study, as well as a disc diffusion method. Results and discussion. Sensitivity of the test-strains and of clinical strains of microorganisms to the resulting compounds was studied. The compounds based on substituted 4-, 5-, 6-, 7-aminoindoles showed different activity against the test strains and experimental strains of microorganisms in vitro. It was found that the marked antibacterial activity was exhibited by the compounds containing a trifluoromethyl group. The most significant activity was noted in amides and pyrroloquinolones based on 4-aminoindole, 6-aminoindole and 7-aminoindole.The most effective compounds with laboratory codes 5D, 7D, 39D, S3, HD, 4D showed a pronounced antibacterial activity. Conclusion. Antimicrobial activity of the substituted amides and pyrroloquinolines on the basis of 4-, 5-, 6-, 7-aminoindoles was etermined in our study, as well as the spectra of their action against Gram-positive and Gram-negative microorganisms, which are causative agents of non-specific and certain specific human infectious diseases. Moreover, we evaluated the synthetic potentials of the substituted 4-, 5-, 6-, 7-aminoindoles as the starting compounds for synthesizing a series of indolylamides and pyrroloquinolines. Also, the prospects for targeted synthesis of biologically active compounds based on indole-type aromatic amines were determined.

scholarly journals Production of a New Thiopeptide Antibiotic, TP-1161, by a Marine Nocardiopsis Species

2010 ◽  
Vol 76 (15) ◽  
pp. 4969-4976 ◽  
Author(s):  
Kerstin Engelhardt ◽  
Kristin F. Degnes ◽  
Michael Kemmler ◽  
Harald Bredholt ◽  
Espen Fj�rvik ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Molecular Taxonomy ◽  
Multidrug Resistant ◽  
Peptide Antibiotic ◽  
Indicator Organisms ◽  
Bacterial Strains ◽  
Pcr Screening ◽  
Vancomycin Resistant ◽  
Antibacterial And Antifungal

ABSTRACT Twenty-seven marine sediment- and sponge-derived actinomycetes with a preference for or dependence on seawater for growth were classified at the genus level using molecular taxonomy. Their potential to produce bioactive secondary metabolites was analyzed by PCR screening for genes involved in polyketide and nonribosomal peptide antibiotic synthesis. Using microwell cultures, conditions for the production of antibacterial and antifungal compounds were identified for 15 of the 27 isolates subjected to this screening. Nine of the 15 active extracts were also active against multiresistant Gram-positive bacterial and/or fungal indicator organisms, including vancomycin-resistant Enterococcus faecium and multidrug-resistant Candida albicans. Activity-guided fractionation of fermentation extracts of isolate TFS65-07, showing strong antibacterial activity and classified as a Nocardiopsis species, allowed the identification and purification of the active compound. Structure elucidation revealed this compound to be a new thiopeptide antibiotic with a rare aminoacetone moiety. The in vitro antibacterial activity of this thiopeptide, designated TP-1161, against a panel of bacterial strains was determined.

Synthesis and Antibacterial Activities of Amidine Substituted Monocyclic β-Lactams

2021 ◽  
Vol 17 ◽  
Author(s):  
Lijuan Zhai ◽  
Lili He ◽  
Yuanbai Liu ◽  
Ko Ko Myo ◽  
Zafar Iqbal ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Species ◽  
Antimicrobial Effect ◽  
Antibacterial Activities ◽  
Lead Target ◽  
Bacterial Strains ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Clinical Interest

Background: Mononcyclic β-lactams are regarded as the most resistant class of β-lactams against a series of β-lactamases though possess limited antibacterial activity. Aztreonam being the first clinically approved monobactam needs broad-spectrum efficacy through structural modification. Objective: We strive to synthesize a number of monocyclic β-lactams by varying the substituents at N1, C3 and C4 positions of azetidinone ring and study the antimicrobial effect on variable bacterial strains. Methods: Seven new monobactam derivatives 23a-g, containing substituted-amidine moieties linked to the azetidinone ring via thiazole linker, were synthesized through multistep synthesis. The final compounds were investigated for their in vitro antibacterial activities using broth microdilution method, against ten bacterial strains of clinical interest. The minimum inhibitory concentrations (MICs) of newly synthesized derivatives were compared with aztreonam, ceftazidime and meropenem, existing clinical antibiotics. Results: All compounds 23a-g showed higher antibacterial activities (MIC 0.25 µg/mL to 64 µg/mL) against tested strains as compared to aztreonam (MIC 16 µg/mL to >64 µg/mL) and ceftazidime (MIC >64 µg/mL). However all compounds, except 23d, exhibited lower antibacterial activity against all tested bacterial strains as compared to meropenem. Conclusion: Compound 23d showed comparable or improved antibacterial activity (MIC 0.25 µg/mL to 2 µg/mL) to meropenem (MIC 1 µg/mL to 2 µg/mL) in case of seven bacterial species. Therefore, compound 23d may be valuable lead target for further investigations against multi-drug resistant Gram-negative bacteria.

In vitro antimicrobial and preliminary phytochemical screening of some Samburu Anti‐diarrhoeal medicinal plants ‐ Kenya

2012 ◽  
Vol 2 (5) ◽  
pp. 217-226
Author(s):  
E. O. Omwenga ◽  
P. O. Okemo ◽  
P. K. Mbugua
Keyword(s):  
Antimicrobial Activity ◽  
Medicinal Plants ◽  
Fungal Pathogens ◽  
Antimicrobial Effect ◽  
Significant Activity ◽  
Bacterial Strains ◽  
Fungal Strains ◽  
Local Isolate ◽  
Agar Disc

The antimicrobial effect of some selected Samburu medicinal plants was evaluated on bacterial strains like Staphylococcus aureus ‐ ATCC 20591, Bacillus subtillis ‐ Local isolate, Salmonella typhi‐ATCC 2202, Escherichia coli‐STD. 25922 and Pseudomonas aeroginosa ‐ ATCC 25852 and fungal strains like Candida albicans ATCC EK138, Aspergillus niger ATCC 16404, Aspergillusflavus‐Local isolate, Fusarium lateritium‐Local isolate, and Penicillium spp.‐ local isolate. Methanol was used as solvent for the extraction from the selected medicinal plants used by the Samburu community. The in vitro antimicrobial activity was performed by agar disc diffusion and micro‐dilution technique. The most susceptible Gram‐positive bacterium was S. aureus, while the most susceptible Gram‐negative bacterium was P. aeroginosa. The extracts of Gomphocarpus fruticosus (L) W.T. Aiton showed less activity against the bacterial strains investigated. The most active antibacterial plants were Euphorbia scarlatica S. Carter, and Euclea divinoram Hiern. Incidentally most of the extracts were inactive against the fungal strains with only a few proving to be slightly active against the C. albicans i.e. Loranthus acaciae Zucc., Kedrostis pseudogijef (Gilg) C. Jeffrey, Euclea divinoram Hiern. and Croton macrostachyus (A. Rich). Benths. The significant antimicrobial activity of active extracts was compared with the standard antimicrobials, cefrodoxima, amoxicillin and fluconazole. The MICs of the most active plants ranged from 18.75mg/ml to 37.50mg/ml. The MBCs ranged between 18.75mg/ml to75mg/ml. These results were significant at P< 0.01. The findings show that most of the medicinal plants used by the Samburu community have some significant activity on the bacterial but not fungal pathogens known to cause diarrhoea.

Sign in / Sign up

Export Citation Format

Share Document