scholarly journals Antibacterial and Antibiofilm Activities of Nigella sativa L. Seed Extracts

2021 ◽  
Vol 38 (1) ◽  
pp. 7-13
Author(s):  
Md Shafiqur Rahman ◽  
Tithi Roy

The emergence of antibiotic-resistant bacteria is a major public health problem. Consequently, the development of new antimicrobials that act on novel bacterial targets and are less susceptible to resistance are of primary importance to researchers in academia and industry alike. The present study was aimed to determine the antimicrobial and antibiofilm activities of Nigella sativa seed extracts. For this, primary (qualitative) and quantitative antibacterial activities of Nigella sativa seed extracts were determined against ten human pathogenic bacteria including four biofilm producing bacterial strains Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus. The antibacterial activities as well as minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extracts were evaluated using disc diffusion and macro-broth dilution methods, respectively. The seed extracts of N. sativa exhibited the highest extract yields (w/v) 23.3% and 21.35% with ethanol and petroleum ether, respectively. The crude extract (essential oil) of petroleum ether exhibited superior antibacterial activity (36 mm in diameter zone of inhibition) against biofilm forming E. coli on a disc diffusion assay at a concentration of 1000 μg/disc when compared to that of ethanolic crude extract. Moreover, the lowest MIC and MBC values were determined as 500 μg/ml and 1500 μg/ml respectively with the same petroleum ether extract against E. coli. However, N. sativa essential oil obtained from petroleum ether extract of seed inhibited 94% biofilm formation of E. coli at 2×MIC concentration. Moreover, at the same concentration (2×MIC), the ethanol extract inhibited 56% biofilm formation of P. aeruginosa. These results consistently revealed that it is possible to isolate novel antimicrobial agents capable of completely eradicating microbial infections including antibiotic resistance. Therefore, bioactive natural products present in plant resources would represent a noteworthy alternative to commercial antibiotics helping treatment of human antibiotic resistant infections. Bangladesh J Microbiol, Volume 38, Number 1, June 2021, pp 7-13

2015 ◽  
Vol 77 ◽  
pp. 624-630 ◽  
Author(s):  
N.H. Nadaf ◽  
S.S. Gawade ◽  
A.S. Muniv ◽  
S.R. Waghmare ◽  
D.B. Jadhav ◽  
...  

2015 ◽  
Vol 13 (4) ◽  
pp. 1020-1028 ◽  
Author(s):  
Stefanie Heß ◽  
Claudia Gallert

Tolerance of antibiotic susceptible and antibiotic resistant Escherichia coli, Enterococcus and Staphylococcus strains from clinical and wastewater samples against ozone was tested to investigate if ozone, a strong oxidant applied for advanced wastewater treatment, will affect the release of antibiotic resistant bacteria into the aquatic environment. For this purpose, the resistance pattern against antibiotics of the mentioned isolates and their survival after exposure to 4 mg/L ozone was determined. Antibiotic resistance (AR) of the isolates was not correlating with higher tolerance against ozone. Except for ampicillin resistant E. coli strains, which showed a trend towards increased resistance, E. coli strains that were also resistant against cotrimoxazol, ciprofloxacin or a combination of the three antibiotics were similarly or less resistant against ozone than antibiotic sensitive strains. Pigment-producing Enterococcus casseliflavus and Staphylococcus aureus seemed to be more resistant against ozone than non-pigmented species of these genera. Furthermore, aggregation or biofilm formation apparently protected bacteria in subsurface layers from inactivation by ozone. The relatively large variance of tolerance against ozone may indicate that resistance to ozone inactivation most probably depends on several factors, where AR, if at all, does not play a major role.


2020 ◽  
Vol 11 (2) ◽  
pp. 1505-1510
Author(s):  
Durga B ◽  
Durga B ◽  
Dass Prakash M V ◽  
Julius A

In recent days, the thirst for the identification of the potential bioactive compounds from the natural sources like medicinal plants is on continuous demand. Among scientists and academicians, it has created many interdisciplinary platforms for research in establishing new drugs from the natural sources. According to many recent studies, Nigella sativa is believed to be the rich source of quinone, an effective bioactive compound with lots of medicinal values. The purpose of this study was to isolate and estimate the quinone in Nigella sativa seed extracts (aqueous and ethanol). Based on the qualitative and quantitative determination, the extracts were further focused for isolation of quinone from both aqueous and ethanolic  extracts of Nigella sativa. The isolated compound is identified by thin layer chromatography and purity is analyzed in High performance liquid chromatography. From the results we obtained, it was very clear that among the aqueous and ethanolic extracts of Nigella sativa, the ethanolic extract has been found with the highest quantity of quinine. This would be predicting that the ethanol extract of Nigella sativa may have good efficacy of pharmacological and therapeutic potentials like antidiabetic, anticancer, antimicrobial, anti-inflammatory properties when compared with the aqueous extract due to the presence of more quinone.


2021 ◽  
Vol 22 (3) ◽  
pp. 397-406
Author(s):  
O.J. Akinjogunla ◽  
A.N. Umo ◽  
M.F. Alozie ◽  
G.O. Oshosanya ◽  
G.I. Saturday

Background: The emergence of multi-drug resistant bacterial strains worldwide has necessitated the scientific search for novel, potent, and affordable antimicrobial agents including medicinal plants and non-antibiotic drugs for therapy of infectious diseases. The objective of this study is to assess in vitro antibacterial activities and time kill kinetics of some non-antibiotic drugs against pathogenic clinical bacterial isolates.Methodology: In vitro antibacterial activities including minimum inhibitory concentration (MIC), minimum bactericidal concentration  (MBC) and time kill kinetics of Amlodipine (AML), Thioridazine (THI) and Promethazine (PRO) against Staphylococcus aureus, coagulase negative staphylococci (CoNS), Streptococcus spp, Escherichia coli, Enterobacter spp, Klebsiella pneumoniae and Pseudomonas aeruginosa clinical isolates were determined using disc diffusion, broth microdilution and plate count techniques.Results: The mean growth inhibition zones by the disc diffusion assay of AML, THI and PRO against the isolates were ≤15.1±1.0 mm with MIC and MBC values ranging from 12.5 to 50μg/ml and 25 to 100μg/ml respectively. The time-kill assay revealed bactericidal effect of AML, THI and PRO on Gram positive bacteria evidenced by mean log reductions in viable bacterial cell counts ranging from 0.13 Log10 to 2.41 Log10 CFU/ml for S. aureus, 0.88 Log10 to 2.08 Log10 CFU/ml for Streptococcus spp, and 0.26 Log10 to 2.34 Log10 CFU/ml for CoNS after ≤30hrs post inoculation at 1xMIC. The range of log reduction in viable cell counts of Gram-negative bacteria exposed to AML, THI and PRO were E. coli (0.11 to 3.23 Log10 CFU/ml), P. aeruginosa (0.52 to 2.56 Log10 CFU/ml), K. pneumoniae (0.85 to 3.0 Log10 CFU/ml) and  Enterobacter spp (0.38 to 2.08 Log10 CFU/ml) after ≤30 hrs post inoculation at 1x MIC.Conclusion: These findings demonstrate in vitro antibacterial efficacies and time kill kinetics of AML, THI and PRO against pathogenic clinical bacterial isolates, which indicate that these non-antibiotic drugs may be useful therapeutic alternatives in the bid to reduce the burden of infectious diseases associated with antibiotic resistant pathogens. Keywords: Amlodipine, Thioridazine, Promethazine, Time-Kill, Kinetics, MIC, MBC, bacteria   French title: Activité antibactérienne et cinétique de destruction du temps de l'amlodipine, de la thioridazine et de la prométhazine contre les isolats bactériens cliniques pathogènes Contexte: L'émergence de souches bactériennes multirésistantes dans le monde a rendu nécessaire la recherche scientifique d'agents antimicrobiens nouveaux, puissants et abordables, notamment des plantes médicinales et des médicaments non antibiotiques pour le traitement des maladies infectieuses. L'objectif de cette étude est d'évaluer les activités antibactériennes in vitro et la cinétique de destruction temporelle de certains médicaments non antibiotiques contre les isolats bactériens cliniques pathogènes. Méthodologie: activités antibactériennes in vitro, y compris la concentration minimale inhibitrice (CMI), la concentration bactéricide minimale (MBC) et la cinétique de destruction du temps de l'amlodipine (AML), de la thioridazine (THI) et de la prométhazine (PRO) contre Staphylococcus aureus, les staphylocoques à coagulase négative (CoNS), Streptococcus spp, Escherichia coli, Enterobacter spp, Klebsiella pneumoniae et Pseudomonas aeruginosa ont été déterminés en utilisant des techniques de diffusion sur disque, de microdilution en bouillon et de numération sur plaque. Résultats: Les zones moyennes d'inhibition de la croissance par le test de diffusion de disque d'AML, THI et PRO contre les isolats étaient ≤15,1±1,0mm avec des valeurs MIC et MBC allant de 12,5 à 50μg/ml et de 25 à 100μg/ml respectivement. Le dosage temporel a révélé un effet bactéricide de la LMA, du THI et du PRO sur les bactéries Gram positives, mis en évidence par des réductions logarithmiques moyennes du nombre de cellules bactériennes viables allant de 0,13 Log10 à 2,41 Log10 CFU/ml pour S. aureus, 0,88 Log10 à 2,08 Log10 CFU/ml pour Streptococcus spp et 0,26 Log10 à 2,34 Log10 CFU/ml pour CoNS après ≤ 30 heures après l'inoculation à 1 x MIC. La plage de réduction logarithmique du nombre de cellules viables de bactéries à Gram négatif exposées à la LMA, au THI et au PRO était E. coli (0,11 à 3,23 Log10 CFU/ml), P. aeruginosa (0,52 à 2,56 Log10 CFU/ml), K. pneumoniae (0,85 à 3,0 Log10 CFU/ml) et Enterobacter spp (0,38 à 2,08 Log10 CFU/ml) après ≤ 30 heures après l'inoculation à 1 x MIC. Conclusion: Ces résultats démontrent une efficacité antibactérienne in vitro et une cinétique de destruction du temps des LMA, THI et PRO contre les isolats bactériens cliniques pathogènes, ce qui indique que ces médicaments non antibiotiques peuvent être des alternatives thérapeutiques utiles dans le but de réduire le fardeau des maladies infectieuses associées aux antibiotiques pathogènes résistants. Mots-clés: Amlodipine, Thioridazine, Prométhazine, Time-Kill, Cinétique, MIC, MBC, bactéries  


2021 ◽  
Vol 12 ◽  
Author(s):  
Sebastian J. Khan ◽  
Amanda M. Osborn ◽  
Prahathees J. Eswara

Antibiotic stewardship is of paramount importance to limit the emergence of antibiotic-resistant bacteria in not only hospital settings, but also in animal husbandry, aquaculture, and agricultural sectors. Currently, large quantities of antibiotics are applied to treat agricultural diseases like citrus greening disease (CGD). The two commonly used antibiotics approved for this purpose are streptomycin and oxytetracycline. Although investigations are ongoing to understand how efficient this process is to control the spread of CGD, to our knowledge, there have been no studies that evaluate the effect of environmental factors such as sunlight on the efficacy of the above-mentioned antibiotics. We conducted a simple disc-diffusion assay to study the efficacy of streptomycin and oxytetracycline after exposure to sunlight for 7- or 14-day periods using Escherichia coli and Bacillus subtilis as the representative strains of Gram-negative and Gram-positive organisms, respectively. Freshly prepared discs and discs stored in the dark for 7 or 14 days served as our controls. We show that the antibiotic potential of oxytetracycline exposed to sunlight dramatically decreases over the course of 14 days against both E. coli and B. subtilis. However, the effectiveness of streptomycin was only moderately impacted by sunlight. It is important to note that antibiotics that last longer in the environment may play a deleterious role in the rise and spread of antibiotic-resistant bacteria. Further studies are needed to substantively analyze the safety and efficacy of antibiotics used for broader environmental applications.


2021 ◽  
Vol 47 (3) ◽  
pp. 1055-1061
Author(s):  
Sartaz Begum ◽  
Jenipher S Asenga ◽  
Valence M.K. Ndesendo ◽  
Baraka L. Ngingo

In vitro antibacterial activities of methanolic leaf and seed extracts of Moringa oleifera grown in Dodoma, Tanzania were evaluated using standard microdilution and disc diffusion methods against extended spectrum beta lactamase producing Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae). Microdilution method showed no activity at concentration of 20 mg/mL for all the extracts except leaf extract which exhibited minimum inhibition at concentration of  2.5 µg/mL for E. Coli but when high concentrations of the extracts were used in the disc diffusion method then the results exhibited the highest killing susceptibility at concentration of 0.4 g/mL with zone of inhibition 31 mm for leaf extract and 26 mm for seed extract against E. coli, and 27 mm for leaf extract and 29 mm for seed extract against K. pneumonia. Additionally, when both extracts were screened qualitatively for phytoconstituents using standard methods, leaf extract confirmed the presence of carbohydrates, cardiac glycosides,  tannins and quinones, and seed extract confirmed the presence of proteins, carbohydrates, cardiac glycosides, alkaloids, terpenoids and quinones. These phytoconstituents can be new sources of future antibiotics that potentially combat the existing problem of antimicrobial resistance and thus, creating an awareness in the community regarding the usage of M. oleifera growing widely but neglected in Tanzania in spite of its nutritional values and traditional uses. Keywords: Moringa oleifera; Phytoconstituents; Antibacterial activity; Escherichia coli and Klebsiella pneumoniae


2020 ◽  
Vol 11 (2) ◽  
pp. 2525-2532
Author(s):  
Sheik Shehensha ◽  
Jyothi M V

Silver nanoparticles were biosynthesized from Nigella sativa seed extracts using ethanol and chloroform. The antibacterial activity of silver nanoparticles against some drug-resistant bacteria has been established, but further study is needed to assess whether these particles could be an option for the treatment and prevention of drug-resistant microbial infections. Synthesized nanoparticles were characterized and screened for their antibacterial properties on resistant strains. The biosynthesized silver nanoparticles were characterized by UV-Visible, FTIR, Dynamic light scattering and Scanning Electron Microscope (SEM) analysis. The antibacterial action of biosynthesized silver nanoparticles was assessed by Microtitre Broth dilution process using Ciprofloxacin as standard, against resistant strains like Pseudomonas aeruginosa, Clostridium difficile, Klebsiella pneumoniae and Streptococcus pyogenes. The Silver nanoparticles obtained from chloroform extract of Nigella sativa seeds were more effective against Pseudomonas aeuruginosa, Clostridium difficile and Streptococcus pyogenes; than ethanolic seed extracts at 120 µL. Our data propose that the silver nanoparticles are effective against a variety of drug-resistant bacteria, which makes them a potential candidate for use in pharmaceutical products that may help to treat drug-resistant pathogens in different clinical environments. The present study focuses on the ability of phytoconstituents capped with silver nitrate can be used to treat infections caused by resistant bacteria


ALCHEMY ◽  
2016 ◽  
Vol 4 (2) ◽  
pp. 93 ◽  
Author(s):  
Zulli Andriani ◽  
Ahmad Ghanaim Fasya ◽  
Ahmad Hanapi

<p align="center"><strong>Abstract</strong></p><p>Red alge <em>Euchema cottonii</em> is one of the biological source that has benefits. The aim of this study is to determine the effectiveness of antibacterial red algae <em>Eucheuma cottonii</em> extract<em>. </em>Isolation of active compounds was performed by maceration method using methanol. The methanol extract was hydrolyzed using HCl 2 N and partitioned by ethyl acetate, chloroform, petroleum ether and <em>n</em>-hexane solvents. The antibacterial assessment was determined using disc diffusion method againts bacteria <em>Staphylococcus aureus </em>and <em>Escherichia coli</em>. Identification of active compound was conducted by reagents test. The results showed that the best solvent to extract algae was methanol with 20.7% rendemen. The methanol extract 4% gives the highest inhibition at concentrations was 7.85 mm; followed by <em>n</em>-hexane and chloroform were 1.0 and 0.6 mm. However, bath ethyl acetate and petroleum ether extract depicted no inhibition zone. The identification test showed the presence of flavonoids, triterpenoids, steroids and alkaloids in the methanol extract. The extract of n-hexane contained triterpenoids and alkaloids, while the chloroform extract contained flavonoids, triterpenoids and alkaloids.</p><p> </p><p><strong>Keyword</strong><strong>s</strong>:  <em>Euchema cottonii</em>, antibacterial, disc diffusion<em></em></p>


2004 ◽  
Vol 18 (5) ◽  
pp. 525-529 ◽  
Author(s):  
Halima Rchid ◽  
Hugues Chevassus ◽  
Rachid Nmila ◽  
Carine Guiral ◽  
Pierre Petit ◽  
...  

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