scholarly journals Key Parameters on the Antibacterial Activity of Silver Camphor Complexes

Antibiotics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 135
Author(s):  
Joana Costa ◽  
Sílvia Sousa ◽  
Adelino Galvão ◽  
J. Mata ◽  
Jorge Leitão ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Antibacterial Activities ◽  
Surface Structures ◽  
Gram Positive ◽  
Gram Negative ◽  
Burkholderia Contaminans ◽  
Positive Strain ◽  
Cell Surface Structures ◽  
Low Sensitivity ◽  
Better Than

Nine new complexes with camphor imine or camphor sulfonimine ligands were synthesized and analytically and spectroscopically characterized, aiming to identify the key parameters that drive the antibacterial activity of the complexes with metal cores and imine substituents with distinct electronic and steric characteristics. The antimicrobial activity of all complexes was evaluated by determining their minimum inhibitory concentrations (MIC) against the Gram-negative Escherichia coli ATCC25922, Pseudomonas aeruginosa 477, and Burkholderia contaminans IST408, and the Gram-positive Staphylococcus aureus Newman. Camphor imine complexes based on the hydroxyl silver center ({Ag(OH)}) typically perform better than those based on the nitrate silver center ({Ag(NO3)}), while ligands prone to establish hydrogen bonding facilitate interactions with the bacterial cell surface structures. A different trend is observed for the silver camphor sulfonimine complexes that are almost non-sensitive to the nature of the metal cores {Ag(OH)} or {Ag(NO3)} and display low sensitivity to the Y substituent. The antibacterial activities of the Ag(I) camphor sulfonimine complexes are higher than those of the camphor imine analogues. All the complexes display higher activity towards Gram-negative strains than towards the Gram-positive strain.

scholarly journals Antibacterial Potential of Aloe weloensis (Aloeacea) Leaf Latex against Gram-Positive and Gram-Negative Bacteria Strains

2019 ◽  
Vol 2019 ◽  
pp. 1-4
Author(s):  
Yohannes Kelifa Emiru ◽  
Ebrahim Abdela Siraj ◽  
Tekleab Teka Teklehaimanot ◽  
Gedefaw Getnet Amare
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Infections ◽  
Inhibition Zone ◽  
Antibacterial Activities ◽  
Maximum Activity ◽  
New Drugs ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative

Objective. To evaluate the antibacterial effects of the leaf latex of Aloe weloensis against infectious bacterial strains. Methods. The leaf latex of A. weloensis at different concentrations (400, 500, and 600 mg/ml) was evaluated for antibacterial activities using the disc diffusion method against some Gram-negative species such as Escherichia coli (ATCC 14700) and Pseudomonas aeruginosa (ATCC 35619) and Gram-positive such as Staphylococcus aureus (ATCC 50080) and Enterococcus fecalis (ATCC 4623). Results. The tested concentrations of the latex ranging between 400 and 600 mg·mL−1 showed significant antibacterial activity against bacterial strain. The highest dose (600 mg/ml) of A. weloensis leaf latex revealed the maximum activity (25.93 ± 0.066 inhibition zone) followed by the dose 500 mg/ml against S. aureus. The lowest antibacterial activity was observed by the concentration 400 mg/ml (5.03 ± 0.03) against E. coli. Conclusion. The results of the present investigation suggest that the leaf latex of A. weloensis can be used as potential leads to discover new drugs to control some bacterial infections.

Antibacterial Activity of Amine-Functionalized Zeolite NaY against Staphylococcus aureus ATCC6538 and Escherichia coli ATCC11229

2015 ◽  
Vol 761 ◽  
pp. 402-406 ◽  
Author(s):  
Siti Aishah Mohd Hanim ◽  
Nik Ahmad Nizam Nik Malek ◽  
Zaharah Ibrahim ◽  
Mashitah Mad Salim ◽  
Nur Isti'anah Ramli ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Inhibition Zone ◽  
Antibacterial Activities ◽  
Gram Positive ◽  
Gram Negative ◽  
Zeolite Nay ◽  
Amine Functionalized ◽  
Diffusion Technique

The antibacterial activity of functionalized zeolite NaY (CBV100) with different concentrations of 3-aminopropyltriethoxysilane (APTES) (0.01, 0.05, 0.20 and 0.40 M) was studied against Staphylococcus aureus ATCC 6538 (Gram positive) and Escherichia coli ATCC 11229 (Gram negative) through disc diffusion technique (DDT). The characterization of functionalized zeolite NaY with fourier transform infrared (FTIR) spectroscopy indicated the attachment of APTES on zeolite NaY. Through DDT, the inhibition zone of functionalized zeolite NaY increased proportionally to the amount of the amine-functional group attached onto zeolite NaY. Functionalized zeolite NaY showed higher antibacterial activity against Gram-positive compared to Gram-negative bacteria. It can be concluded from this study that amine-functionalized zeolite NaY shows evidence of antibacterial activities.

scholarly journals Antibacterial Activities of Xanthium Strumarium L.

2018 ◽  
Vol 29 ◽  
pp. 70-77 ◽  
Author(s):  
Anjana Devkota ◽  
Ritu Kumari Das
Keyword(s):  
Antibacterial Activity ◽  
Pathogenic Bacteria ◽  
Antibacterial Activities ◽  
Diffusion Method ◽  
Xanthium Strumarium ◽  
Distilled Water ◽  
Leaf Extracts ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Antibacterial activities of Xanthium strumarium L. (Asteraceae) was carried out in laboratory. Distilled water and methanol extracts of the leaves of plant was prepared. The antibacterial activity was studied against six pathogenic bacteria, three gram negative: Klebsiella pneumoniae (ATCC 15380), Proteus mirabilis (ATCC 49132), Escherichia coli (ATCC 25922) and three gram positive: Bacillus subtilis (ATCC 6633), Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 25932) at different concentrations (50 mg/ml, 100 mg/ml, 150 mg/ml, 200 mg/ ml, 250 mg/ml) of leaf extracts of X. strumurium. The phytochemical screening depicted the presence of terpenoids, saponins, flavonoids, tannins and alkaloids. The antibacterial activity of extracts was determined by disc diffusion method and zone of inhibition (ZOI) was measured. Gram negative bacteria was found more resistant than gram positive bacteria. The most susceptible bacterium was S. aureus while the most resistant bacterium was E. coli. Methanolic extract was found more effective than distilled water. These findings suggest that extracts obtained from leaves of X. strumurium possess biobactericidal potential, which can suitably be exploited for making antibacterial drugs.J. Nat. Hist. Mus. Vol. 29, 2015, Page: 70-77

scholarly journals Molecular Computation and Antibacterial Activity of Cu (II) Complex of Naphthaldehyde Thiosemicarbazone

2020 ◽  
pp. 85-93
Keyword(s):  
Antibacterial Activity ◽  
Molecular Geometry ◽  
Inhibition Zone ◽  
Antibacterial Activities ◽  
Spectral Measurements ◽  
Gram Positive ◽  
Activity Data ◽  
Gram Negative ◽  
Diffusion Technique ◽  
Parent Ligand

Copper (II) complex of naphthaldehyde thiosemicarbazone (L) has been synthesized and characterized by melting points, conductance, magnetic, infrared, and ESI-MS spectral measurements in addition to elemental analysis. A tetrahedral structure is suggested for the complex. The antibacterial activities of the complex and ligand were evaluated by the disc diffusion technique. Pure bacteria cultures of Bacillus subtilis (Gram-positive) and Escherichia coli (Gram-negative) were used to check the antibacterial activities of the synthesized compounds. Antibacterial activities were compared by measuring the inhibition zone diameter and chloramphenicol was used as a reference. Both the compounds showed significant antibacterial activity in different range against gram-positive & gram-negative bacteria. The antibacterial activity data also show that the Cu(II) complex to be more effective than the parent ligand. Molecular geometry of the complex has been optimized by ChemDraw Ultra 12.0 and then MM2 calculation has been done.

In Vitro Antibacterial Activities and Mechanisms of Action of Fatty Acid Monoglycerides Against Four Foodborne Bacteria

2020 ◽  
Vol 83 (2) ◽  
pp. 331-337
Author(s):  
WENYUE WANG ◽  
RUI WANG ◽  
GUIJU ZHANG ◽  
FANGLI CHEN ◽  
BAOCAI XU
Keyword(s):  
Antibacterial Activity ◽  
Antibacterial Activities ◽  
Carbon Chain ◽  
Antimicrobial Activities ◽  
Inhibitory Effect ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Alkaline Conditions

ABSTRACT Naturally occurring monoglyceride esters of fatty acids have been associated with a broad spectrum of antimicrobial activities. We used an automated turbidimetric method to measure the MIC and assess the antimicrobial activity of five monoglycerides (monocaprin, monolaurin, monomyristin, monopalmitin, and monostearin) against pathogenic strains of Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli. The antibacterial activity of monocaprin was highest because its carbon chain is shorter than those of other monoglycerides. The MICs of monocaprin against S. aureus, B. subtilis, P. aeruginosa, and E. coli were 0.32, 0.32, 2.5, and 2.5 mg/mL, respectively. Monocaprin had antibacterial activity under neutral and alkaline conditions (pH 7.0 to 9.0) but had no inhibitory effect on S. aureus, B. subtilis, and E. coli under weakly acidic conditions (pH 6.0). The antibacterial mechanism of monocaprin against gram-positive strains (S. aureus and B. subtilis) resulted from destruction of the cell membrane. In contrast, the antibacterial activity of monocaprin against gram-negative strains (P. aeruginosa and E. coli) was attributed to damage to lipopolysaccharides in the cell walls. Because of its inhibitory effect on both gram-positive and gram-negative bacteria, monocaprin could be used as an antibacterial additive in the food industry. HIGHLIGHTS

The Effects of Natural Dopant Acids on Morphologies and Antibacterial Activity of Polyaniline

2013 ◽  
Vol 650 ◽  
pp. 249-252 ◽  
Author(s):  
Jia Li Mu ◽  
Wen Jun Fan ◽  
Shao Yun Shan ◽  
Ting Wei Hu ◽  
Ya Ming Wang ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Salicylic Acid ◽  
Citric Acid ◽  
Rosin Acid ◽  
Antibacterial Activities ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Bacillus Coli

Polyaniline(PANI) doped by natural acid(citric acid, salicylic acid or rosin acid)solutions was synthesized using aniline as monomer and ammonium peroxydisulfate ((NH4)2S2O8) as oxidant. The antibacterial activities of the PANI against Gram positive bacteria(Bacillus megatherium, Bacillus subtilis, Bacillus cereus and Staphylo-coccus aureus) and Gram negative bacteria(Bacillus coli) were investigated. It was shown that PANI doped by citric acid possessed the better antibacterial activity against the selected species of Gram positive bacteria and Gram negative bacteria than PANI doped by rosin acid. PANI doped by salicylic acid exhibited ascendant antibacterial activities against Gram positive bacteria, but it has little antibacterial activity against the Gram negative bacteria.

scholarly journals Antibacterial Activity of Murrayaquinone A and 6-Methoxy-3,7-dimethyl-2,3-dihydro-1H-carbazole-1,4(9H)-dione

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Biswanath Chakraborty ◽  
Suchandra Chakraborty ◽  
Chandan Saha
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antibacterial Activity ◽  
Bacillus Subtilis ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Antibacterial Activities ◽  
Gram Positive ◽  
Gram Negative ◽  
Naturally Occurring

The antibacterial activity of Murrayaquinone A (10), a naturally occurring carbazoloquinone alkaloid, and 6-methoxy-3,7-dimethyl-2,3-dihydro-1H-carbazole-1,4(9H)-dione (11), a synthetic carbazoloquinone, both obtained during the development of the synthesis of Carbazomycin G, having unique quinone moiety, was studied against Gram-positive (Bacillus subtilisandStaphylococcus aureus) and Gram-negative (Escherichia coliandPseudomonassp.) bacteria. Compound10showed antibacterial activities against both ofEscherichia coliandStaphylococcus aureuswhereas compound11indicated the activity againstStaphylococcus aureusonly. Both compounds10and11exhibited minimum inhibitory concentration (MIC) of 50 μg mL−1againstStaphylococcus aureus.

scholarly journals Pyoverdines are essential for the antibacterial activity of Pseudomonas chlororaphis YL-1 under low-iron conditions

2021 ◽  
Author(s):  
Youzhou Liu ◽  
Chen Dai ◽  
Yaqiu Zhou ◽  
Junqing Qiao ◽  
Bao Tang ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Sufficient Conditions ◽  
Antibacterial Activities ◽  
Pseudomonas Chlororaphis ◽  
Iron Starvation ◽  
Gram Positive ◽  
Biosynthesis Gene Cluster ◽  
Gram Negative ◽  
Wide Range

Pseudomonas chlororaphis YL-1 has extensive antimicrobial activities against phytopathogens, and its genome harbors pyoverdine (PVD) biosynthesis gene cluster. The alternative sigma factor PvdS in Pseudomonas aeruginosa PAO1, acts as a critical regulator in response to iron starvation. The assembly of the PVD backbone starts with peptide synthetase enzyme PvdL. PvdF catalyzes formylation of L-OH-Orn to produce L-N5-hydroxyornithine. Here, we describe the characterization of PVD production in YL-1 and its antimicrobial activity as compared with its PVD-deficient mutants ΔpvdS, ΔpvdF, and ΔpvdL, that were obtained using a sacB-based site-specific mutagenesis strategy. Using in vitro methods, we examined the effect of exogenous iron under low-iron conditions and iron-chelating agent under iron-sufficient conditions on PVD production, antibacterial activity, and the relative expression of PVD transcription factor gene pvdS in YL-1. We found that strain YL-1, mutant ΔpvdF, and complemented strain ΔpvdS(pUCP26-pvdS) produced visible PVDs and demonstrated a wide range of inhibitory effects against Gram-negative and Gram-positive bacteria in vitro under low-iron conditions, and that with the increase of iron its PVD production and antibacterial activity were reduced. The antibacterial compounds produced by strain YL-1 in low-iron conditions were PVDs based on the liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Moreover, the antibacterial activity observed in vitro was correlated with in vivo control efficacies of strain YL-1 against rice bacterial leaf blight (BLB) disease caused by Xanthomonas oryzae pv. oryzae （Xoo）. Collectively, PVDs are responsible for the antibacterial activities of strain YL-1 under both natural and induced low-iron conditions. IMPORTANCE: The results demonstrated that PVDs are essential for the broad-spectrum antibacterial activities of strain YL-1 against both Gram-positive and Gram-negative bacteria in low-iron conditions. Our findings also highlight the effect of exogenous iron on the production of PVD and the importance of this bacterial product in bacterial interactions. As a biocontrol agent, PVDs can directly inhibit the proliferation of the tested bacteria in addition to participating in iron competition.

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.

scholarly journals Antibacterial activity of cobalt(II) complexes with some benzimidazole derivatives

2008 ◽  
Vol 73 (12) ◽  
pp. 1153-1160 ◽  
Author(s):  
S.O. Podunavac-Kuzmanovic ◽  
V.M. Leovac ◽  
D.D. Cvetkovic
Keyword(s):  
Antibacterial Activity ◽  
Chemical Structure ◽  
Antibacterial Activities ◽  
Benzimidazole Derivatives ◽  
Wall Structure ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative

The antibacterial activities of cobalt(II) complexes with two series of benzimidazoles were evaluated in vitro against three Gram-positive bacterial strains (Bacillus cereus, Staphylococcus aureus, and Sarcina lutea) and one Gram-negative isolate (Pseudomonas aeruginosa). The minimum inhibitory concentration was determined for all the complexes. The majority of the investtigated complexes displayed in vitro inhibitory activity against very persistent bacteria. They were found to be more active against Gram-positive than Gram-negative bacteria. It may be concluded that the antibacterial activity of the compounds is related to the cell wall structure of the tested bacteria. Comparing the inhibitory activities of the tested complexes, it was found that the 1-substituted- -2-aminobenzimidazole derivatives were more active than complexes of 1-substituted- 2-amino-5,6-dimethylbenzimidazoles. The effect of chemical structure on the antibacterial activity is discussed.

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