scholarly journals SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF SOME 1,4- AND 1,4,5-SUBSTITUTED-1H-1,2,3TRIAZOLES IN RELATION TO THE STAPHYLOCOCCUS AUREUS STRAIN

2018 ◽  
Vol 62 (3) ◽  
pp. 293-297 ◽  
Author(s):  
A. V. Zuraev ◽  
A. V. Lishai ◽  
Yu. V. Grigoriev ◽  
O. A. Ivashkevich
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Catalytic System ◽  
Bactericidal Activity ◽  
Cycloaddition Reaction ◽  
Antibacterial Activities ◽  
Aureus Strain ◽  
Derivatives Of

A number of 1,4- and 1,4,5-triazoles have been synthesized using a modified catalytic system for the Huisgen [3+2] cycloaddition reaction. The bactericidal activity of the synthesized compounds has been studied. The synthesized derivatives of 1H-1,2,3-triazoles have demonstrated higher antibacterial activities in relation to the pathogen Staphylococcus aureus strain which can be comparable with the clinically used antibiotic “Cefotaxime”.

scholarly journals Synthesis and Antibacterial Activities of Coumarins with an Acyl Amino Side Chain

2021 ◽  
Vol 68 (1) ◽  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Antibacterial Agents ◽  
Antibacterial Activities ◽  
Ring Structure ◽  
Coumarin Derivatives ◽  
Anti Cancer ◽  
Synthetic Reactions ◽  
Derivatives Of

Coumarin is a heterocyclic moiety containing benzo pyran ring structure. It is widely distributed in the plant kingdom as a glycoside. Many compounds of medicinal and pharmaceutical importance possess coumarin ring structure. Drugs with coumarin structure can be synthesized by many well-known synthetic reactions. Coumarin derivatives were found to be antibacterial, anticoagulant, antiinflammatory, anti-HIV, anti-cancer and antioxidant. As part of the search for new and effective antibacterial agents, eight novel derivatives of coumarins were synthesized by Mannich reaction. All the compounds were evaluated for antibacterial activity against Staphylococcus aureus and Escherichia coli using ciprofloxacin as standard and DMSO as solvent. Three of the synthesized derivatives exhibited good antibacterial activity against Staphylococcus aureus and Escherichia coli. The work must be extended so as to develop coumarin derivatives into highly effective antibacterial agents.

SYNTHESIS AND ANTIBACTERIAL ACTIVITY OF NEW DERIVATIVES OF 2-OXO-2,5-DIHYDROFURANS CONTAINING AN OXOTHIAZOLIDINYLIDENE RING

2020 ◽  
Vol 54 (1 (251)) ◽  
pp. 12-16
Author(s):  
G.G. Tokmajyan ◽  
L.V. Karapetyan ◽  
R.V. Paronikyan ◽  
H.M. Stepanyan
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Shigella Flexneri ◽  
Antibacterial Activities ◽  
Gram Positive ◽  
Gram Negative ◽  
Esherichia Coli ◽  
Derivatives Of

ring were successfully synthesized based on thiosemicarbazones of 3-acetyl-2-oxo-2,5-dihydrofurans. The synthesized compounds exhibited moderate to defined antibacterial activities against Gram-positive (Staphylococcus aureus 209P and 1) and Gram-negative (Shigella Flexneri 6858, Esherichia coli 0–55) bacteria compared to furazolidone.

Microwave assisted synthesis of novel Pyrazole derivatives and their biological evaluation as anti-bacterial agents

2020 ◽  
Vol 23 ◽  
Author(s):  
Hadis Khodadad ◽  
Farhad Hatamjafari ◽  
Khalil Pourshamsian ◽  
Babak Sadeghi
Keyword(s):  
Antibacterial Activity ◽  
Aromatic Aldehydes ◽  
Catalytic Amount ◽  
Antibacterial Activities ◽  
Structural Features ◽  
Biological Evaluation ◽  
Aureus Strain ◽  
Microwave Assisted Synthesis ◽  
Pyrazole Derivatives ◽  
Microwave Assisted

Aim and Objective: Microwave-assisted condensation of acetophenone 1 and aromatic aldehydes 2 gave chalcone analogs 3, which were cyclized to pyrazole derivatives 6a-f via the reaction with hydrazine hydrate and oxalic acid in the presence of the catalytic amount of acetic acid in ethanol. Materials and Methods: The structural features of the synthesized compounds were characterized by melting point, FT-IR, 1H, 13C NMR and elemental analysis. Results: The antibacterial activities of the synthesized pyrazoles was evaluated against three gram-positive bacteria such as Enterococcus durans, Staphylococcus aureus, Bacillus subtilis and two gram-negative bacteria such as Escherichia coli and Salmonella typhimurium. Conclusion: All the synthesized pyrazoles showed relatively high antibacterial activity against S. aureus strain and none of them demonstrated antibacterial activity against E. coli.

scholarly journals ISOLATION AND CHARACTERIZATION OF ACTINOMYCETES FROM SOIL OF AD-DAWADMI, SAUDI ARABIA AND SCREENING THEIR ANTIBACTERIAL ACTIVITIES

2017 ◽  
Vol 9 (10) ◽  
pp. 276 ◽  
Author(s):  
Gouse Basha Sheik ◽  
Muazzam Sheriff Maqbul ◽  
Gokul Shankar S. ◽  
Ranjith M S
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Antibacterial Activities ◽  
Soil Samples ◽  
Streptomyces Sp ◽  
Crude Extracts ◽  
Test Organisms ◽  
Inhibition Zones

Objective: To isolate and characterize novel actinomycetes and to evaluate their antibacterial activity against drug-resistant pathogenic bacteriaMethods: In the present study, 19 soil samples were collected from different localities of Ad-Dawadmi, Saudi Arabia. Actinomycetes were isolated from these samples using serial dilution and plating method on Actinomycetes isolation agar supplemented with nalidixic acid and actidione to inhibit bacteria and fungi. Crude extracts of potential actinomycetes were produced by submerged fermentation. The antimicrobial activity of crude extracts of actinomycetes was tested against different bacteria using the agar well diffusion method. Characterization of the isolates was done by morphological, physiological and biochemical methods.Results: A total of 9 (47%) isolates of actinomycetes were isolated from 19 different soil samples tested. Among them, 4 (44%) isolates confirmed as Streptomyces sp. showed potential antimicrobial activity against one or more test organisms. Crude extracts were made from these 4 actinomycetes isolates(DOM1, DOM3, DP3, DP4)and tested for their antibacterial activities against 4 different clinical bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus). Crude extract from DP3 isolate showed highest antibacterial activity against all the four test organisms (28 mm, 21 mm, 20 mm and 18 mm) respectively and DP4 showed lowest antibacterial activity against all the four test organisms (14 mm, 12 mm, 0 mm, 6 mm) respectively. The highest zone of inhibition was shown by DP3 against Staphylococcus aureus (28 mm) and Escherichia coli was resistant for DP4. Most of the Inhibition zones produced by crude extracts showed significant differences when compared with control, tested against test organisms (P<0.05). Inhibition zones produced by DP3 and DOM1 against Staphylococcus aureus were 28 mm and 23 mm, respectively which were strong active when compared with control Ciprofloxacin (18 mm).Conclusion: Further studies for purification of bioactive metabolites and molecular characterization analysis of isolated Streptomyces sp. are in progress which would be helpful in discovering novel compounds of commercial value.

scholarly journals Synthesis of 14-Substituted-14H-Dibenzo[a,j]Xanthene Derivatives in Presence of Effective Synergetic Catalytic System Bleaching Earth Clay and PEG-600

Catalysts ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1294
Author(s):  
Sandeep T. Atkore ◽  
Giribala M. Bondle ◽  
Pranita V. Raithak ◽  
Vinod T. Kamble ◽  
Ravi Varala ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Catalytic System ◽  
Present Method ◽  
Condensation Reaction ◽  
Bleaching Earth ◽  
Product Yield ◽  
Xanthene Derivatives ◽  
Peg 600

The synthesis of 14-aryl 14H-dibenzo[a,j]xanthenes is achieved by a simple condensation reaction between β-naphthol with aryl or alkyl aldehydes in an effective synergetic catalytic system created by combining basic bleaching earth clay and PEG-600. The advantages of the present method include catalyst recyclability, superior product yield, a shorter reaction time and the avoidance of hazardous reagents. Synthesized xanthene derivatives were also screened for their antibacterial activity against Staphylococcus aureus (MTCC 96) and Pseudomonas aeruginosa (Wild).

Nemonoxacin enhances antibacterial activity and anti-resistant mutation ability of vancomycin against methicillin-resistant Staphylococcus aureus in an in vitro dynamic pharmacokinetic/pharmacodynamic model

2021 ◽  
Author(s):  
Junchen Huang ◽  
Siwei Guo ◽  
Xin Li ◽  
Fang Yuan ◽  
You Li ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Bactericidal Activity ◽  
Pharmacodynamic Model ◽  
Methicillin Resistant ◽  
Mutant Prevention Concentration ◽  
Mrsa Infection ◽  
Independent Risk Factors ◽  
Resistant Mutation

Reduced susceptibility and emergence of resistance to vancomycin in methicillin-resistant Staphylococcus aureus (MRSA) have led to the development of various vancomycin based combinations. Nemonoxacin is a novel nonfluorinated quinolone with antibacterial activity against MRSA. The present study aimed to investigate the effects of nemonoxacin on antibacterial activity and the anti-resistant mutation ability of vancomycin for MRSA and explore whether quinolone resistance genes are associated with a reduction in the vancomycin minimal inhibitory concentration (MIC) and mutant prevention concentration (MPC) when combined with nemonoxacin. Four isolates, all with a vancomycin MIC of 2 μg/mL, were used in a modified in vitro dynamic pharmacokinetic/pharmacodynamic model to investigate the effects of nemonoxacin on antibacterial activity (M04, M23 and M24) and anti-resistant mutation ability (M04, M23 and M25, all with MPC ≥19.2 μg/mL) of vancomycin. The mutation sites of gyrA , gyrB , parC , and parE of 55 clinical MRSA isolates were sequenced. We observed that in M04 and M23, the combination of vancomycin (1g q12h) and nemonoxacin (0.5g qd) showed a synergistic bactericidal activity and resistance enrichment suppression. All clinical isolates resistant to nemonoxacin harbored gyrA (S84→L) mutation; gyrA (S84→L) and parC (E84→K) mutations were the two independent risk factors for the unchanged vancomycin MPC in combination. Nemonoxacin enhances the bactericidal activity and suppresses resistance enrichment ability of vancomycin against MRSA with a MIC of 2 μg/mL. Our in vitro data support the combination of nemonoxacin and vancomycin for the treatment of MRSA infection with a high MIC.

scholarly journals Antibacterial and Cytotoxic Activities of the Sesquiterpene Lactones Cnicin and Onopordopicrin

2011 ◽  
Vol 6 (2) ◽  
pp. 1934578X1100600 ◽  
Author(s):  
Sandra M. Bach ◽  
Mario A. Fortuna ◽  
Rodgoun Attarian ◽  
Juliana T. de Trimarco ◽  
César A. N. Catalán ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Sesquiterpene Lactones ◽  
Antibacterial Activities ◽  
Chloroform Extract ◽  
Cytotoxic Activities ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
High Cytotoxicity

The antimicrobial and cytotoxic activities of chloroform extracts from the weeds Centaurea tweediei and C. diffusa, and the main sesquiterpene lactones isolated from these species, onopordopicrin and cnicin, respectively, were assayed. Results show that the chloroform extracts from both Centaurea species possess antibacterial activities against a panel of Gram-positive and Gram-negative bacteria. Remarkable antibacterial activity against methicillin-resistant Staphylococcus aureus was also measured. Both the extracts and the purified sesquiterpene lactones show high cytotoxicity against human-derived macrophages. Despite this cytotoxicity, C. diffusa chloroform extract and cnicin are attractive candidates for evaluation as antibiotics in topical preparations against skin-associated pathogens.

scholarly journals In vitro antibacterial activity of omeprazole and its selectivity for Helicobacter spp. are dependent on incubation conditions.

1996 ◽  
Vol 40 (3) ◽  
pp. 621-626 ◽  
Author(s):  
J E Sjöström ◽  
J Fryklund ◽  
T Kühler ◽  
H Larsson
Keyword(s):  
Antibacterial Activity ◽  
Proton Pump Inhibitors ◽  
Proton Pump ◽  
Bactericidal Activity ◽  
Fetal Calf Serum ◽  
Calf Serum ◽  
Antibacterial Activities ◽  
In Vitro Antibacterial Activity ◽  
H Pylori

Factors affecting the in vitro antibacterial activity of omeprazole were studied. Our data show that 3H-labeled omeprazole covalently bound to Helicobacter pylori and to other gram-negative and gram-positive bacteria. The compound was found to bind to a broad range of proteins in H. pylori, and at pH 5, binding was enhanced 15-fold compared with binding at pH 7. The bactericidal activity correlated to the degree of binding, and at pH 5, a pH at which omeprazole readily converts to the active sulfenamide form, beta-mercaptoethanol, a known scavenger of sulfenamide, and fetal calf serum, to which noncovalent protein binding of omeprazole is known to occur, reduced the level of binding and almost entirely abolished the bactericidal activity. At pH 7 the killing activities of omeprazole and structural analogs (e.g., proton pump inhibitors) were dependent on the time-dependent conversion (half-life) to the corresponding sulfenamide. The bactericidal activity exerted by the sulfenamide form at pH 5 was not specific for the genus Helicobacter. However, in brucella broth at pH 7 with 10% fetal calf serum, only Helicobacter spp. were susceptible to omeprazole, with MBCs in the range of 32 to 64 micrograms/ml, and MBCs for more stable proton pump inhibitors were higher. Wild-type H. pylori and its isogenic urease-deficient mutant were equally susceptible to omeprazole. Thus, the urease is not a lethal target for omeprazole action in H. pylori. In conclusion, the antibacterial activities of omeprazole and analogs are dependent on pH and the composition of the medium used. Thus, at a low pH in buffer, these compounds have a nonselective action, whereas in broth at neutral pH, the mechanism of action is selective for Helicobacter spp.

scholarly journals Defective Bactericidal Activity of Monocytes in Fatal Granulomatous Disease

Blood ◽  
1969 ◽  
Vol 33 (6) ◽  
pp. 813-820 ◽  
Author(s):  
GLENN E. RODEY ◽  
B. H. PARK ◽  
DOROTHY B. WINDHORST ◽  
ROBERT A. GOOD
Keyword(s):  
Staphylococcus Aureus ◽  
Bactericidal Activity ◽  
Peripheral Blood ◽  
Cell Suspensions ◽  
Aureus Strain ◽  
Granulomatous Disease ◽  
Normal Controls

Abstract The bactericidal activity of monocyte-rich cell suspensions obtained from the peripheral blood of patients with fatal granulomatous disease (FGD), their mothers and normal controls was studied. Defective killing of Staphylococcus aureus, Strain 502A, by monocyte-rich cell suspensions from children with FGD was found when compared with monocyte-rich suspensions from normal controls. This defect, less severe, was also observed in the mothers of affected patients. In this selected population of mothers, the monocyte defect varied in parallel with the previously described neutrophil defect.

scholarly journals Chemical composition, antibacterial activity and related mechanism of valonia and shell from Quercus variabilis Blume (Fagaceae) against Salmonella paratyphi a and Staphylococcus aureus

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Dan Zhou ◽  
Ze-Hua Liu ◽  
Dong-Mei Wang ◽  
Deng-Wu Li ◽  
Li-Na Yang ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Chemical Composition ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Antibacterial Mechanism ◽  
Natural Antimicrobials ◽  
Butanol Fraction ◽  
Quercus Variabilis ◽  
Crude Extracts

Abstract Background Plant secondary metabolites and phytochemicals that exhibit strong bioactivities have potential to be developed as safe and efficient natural antimicrobials against food contamination and addressing antimicrobial resistance caused by the overuse of chemical synthetic preservative. In this study, the chemical composition, antibacterial activities and related mechanism of the extracts of the valonia and the shell of Quercus variabilis Blume were studied to determine its potential as a safe and efficient natural antimicrobial. Methods The phenolic compositions of valonia and shell extracts were determined by folin-ciocalteau colourimetric method, sodium borohydride/chloranil-based assay and the aluminium chloride method and then further identified by the reverse-phase HPLC analysis. The antibacterial activities of valonia and shell extracts were evaluated by the agar disk diffusion method and agar dilution method. The related antibacterial mechanism was explored successively by the membrane of pathogens effect, phosphorous metabolism, whole-cell proteins and the microbial morphology under scanning electron microscopy. Results The n-butanol fraction and water fraction of valonia along with n-butanol fraction of the shell contains enrich phenolics including ellagic acid, theophylline, caffeic acid and tannin acid. The n-butanol fraction and ethanol crude extracts of valonia exhibited strong antibacterial activities against Salmonella paratyphi A (S. paratyphi A) and Staphylococcus aureus (S. aureus) with the DIZ values ranged from 10.89 ± 0.12 to 15.92 ± 0.44, which were greater than that of the Punica granatum (DIZ: 10.22 ± 0.18 and 10.30 ± 0.21). The MIC values of the n-butanol fraction and ethanol crude extracts of valonia against S. paratyphi A and S. aureus were 1.25 mg/ml and 0.625 mg/ml. The related antibacterial mechanism of n-butanol fraction and ethanol crude extracts of valonia may be attributed to their strong impact on membrane permeability and cellular metabolism. Those extracts exhibited strong antibacterial activity according to inhibit the synthesis of bacterial proteins and seriously change morphological structure of bacterial cells. Conclusions The n-butanol fraction and ethanol crude extracts of valonia had reasonably good antibacterial activities against S. paratyphi A and S. aureus. This study suggests possible application of valonia and shell as natural antimicrobials or preservatives for food and medical application.

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