scholarly journals Antimicrobial activity of crude extracts and fractions of Vernonia polyanthes Less (assa-peixe) flowers

2015 ◽  
Vol 17 (4 suppl 2) ◽  
pp. 909-914 ◽  
Author(s):  
K.K. WALTRICH ◽  
J. HOSCHEID ◽  
I.S. PROCHNAU
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Folk Medicine ◽  
Ethyl Acetate Fraction ◽  
Extraction Methods ◽  
Agar Diffusion ◽  
Test Organisms ◽  
Agar Diffusion Assay ◽  
Macerated Extract ◽  
Diffusion Assay

ABSTRACT Vernonia polyanthes, known as “assa-peixe”, is a plant native to Brazil, and the decoction or infusion of its flowers, roots and leaves are used in folk medicine, being considered sources of diuretic, balsamic, anti-rheumatic substances, and are used in cases of bronchitis and persistent cough. The aim of the study was to evaluate the antimicrobial activity of the extract/fractions obtained by methanol maceration and infusion of V. polyanthes flower, also including qualitative identification of flower compounds, through phytochemical evaluation, using colorimetric tests. Identification tests for the presence of anthraquinones, tannins, flavonoids, saponins and alkaloids were performed. Microbiological evaluation was made through agar diffusion assay, using Escherichia coli, Staphylococcus aureus and Pseudomonasaeruginosa as test organisms. From the performed colorimetric tests it was possible to verify the presence of tannins and flavonoids in both extracts. Alkaloids were also observed in the macerated extract. The ethyl acetate fraction from the agar diffusion assay, from both extracts, presented microbial activity over Staphylococcus aureus. It was possible to qualitatively identify the floral compounds, and to show the differences between extraction methods, being methanol considered the best solvent to the extraction.

Novel Quantitative Assays for Estimating the Antimicrobial Activity of Fresh Garlic Juice†,‡

2001 ◽  
Vol 64 (2) ◽  
pp. 189-194 ◽  
Author(s):  
R. UNAL ◽  
H. P. FLEMING ◽  
R. F. McFEETERS ◽  
R. L. THOMPSON ◽  
F. BREIDT ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Dose Response ◽  
Ratio Method ◽  
E Coli ◽  
Agar Diffusion ◽  
Dilution Assay ◽  
Agar Diffusion Assay ◽  
Slope Ratio Method ◽  
Diffusion Assay ◽  
Broth Dilution

Novel agar diffusion and broth dilution assays were developed for quantitatively estimating the antimicrobial activity of fresh garlic juice. Bacteria found to be inhibited by garlic juice in agar diffusion assay included two gram-positive and five gram-negative species. Leuconostoc mesenteroides was not inhibited. Escherichia coli B-103 (HB101, with pJH101, ampicillin resistant, 100 μg ml−1) was inhibited and chosen as the standard culture for quantitative assays. The agar diffusion assay was based on the slope ratio method, where the slope of dose response for garlic juice was divided by the slope of dose response for methylmethane thiosulfonate (MMTSO2). Juice from fresh garlic varied in activity between 1.76 and 2.31 μg of MMTSO2 per mg of garlic juice. The activity of juice decreased during 11 months of storage of garlic cloves at 5°C from 2.31 to less than 0.1 μg of MMTSO2 per mg of juice. The broth dilution assay also used the E. coli B-103 culture, which permitted selective enumeration of this bacterium when 100 μg ml−1 of ampicillin was incorporated into the enumerating agar. Selective enumeration was essential since the garlic juice was not sterile and, thus, contained natural flora. Growth of E. coli was unaffected by 0.1%, delayed by 0.25%, and completely inhibited at 0.5 and 2% garlic juice in broth during 24 h of incubation at 37°C. The minimum inhibition concentration of garlic juice by broth dilution assay was, thus, estimated to be 0.5%, which is equivalent to 3.46 μg of MMTSO2 per mg of garlic juice by the agar diffusion assay.

Short microwave-assisted modular synthesis of naturally occurring oxygenated bibenzyls

2015 ◽  
Vol 70 (9) ◽  
pp. 637-641 ◽  
Author(s):  
Jürgen Krauss ◽  
Ursula Kopp ◽  
Franz Bracher
Keyword(s):  
Antimicrobial Activity ◽  
Natural Products ◽  
Microwave Assisted ◽  
Modular Synthesis ◽  
Agar Diffusion ◽  
Naturally Occurring ◽  
Agar Diffusion Assay ◽  
Diffusion Assay

AbstractThe naturally occurring oxygenated bibenzyls lunularin and m-O-methyllunularin were prepared in a modular synthesis in four steps from two appropriate iodophenols and trimethylsilylacetylene utilizing microwave-assisted Sonogashira couplings as the crucial steps. The antimicrobial activity of the resulting natural products was evaluated in an agar diffusion assay.

In Vitro Antifungal Activity of Several Antimicrobial Compounds against Penicillium expansum

2002 ◽  
Vol 65 (5) ◽  
pp. 834-839 ◽  
Author(s):  
M. E. VENTURINI ◽  
D. BLANCO ◽  
R. ORIA
Keyword(s):  
Hydrogen Peroxide ◽  
Antimicrobial Activity ◽  
Prevention And Control ◽  
Penicillium Expansum ◽  
Agar Diffusion ◽  
Agar Diffusion Assay ◽  
And Control ◽  
Diffusion Assay ◽  
Broth Dilution

Fungicides used in the prevention and control of mold rots in stored apples are subjected to legal, social, and biological limitations. The aim of this study was to find an alternative to postharvest fungicides currently used in the prevention and control of blue mold rot caused by Penicillium expansum in apples. For this purpose, the antimicrobial activity and MIC of several substances against P. expansum were evaluated in vitro using different end point methods: agar diffusion assay, volatility method, and agar dilution and broth dilution MIC assays. Most of the substances tested are common food ingredients and have a recognized antimicrobial activity. Essential oils, such as thymol, eugenol, citral and cineole, vanillin, sodium hypochlorite, acetic acid, potassium sorbate, and hydrogen peroxide, were the substances evaluated. Thymol and citral were the essential oil components that showed the greatest inhibitory effects. The effectiveness of 5 and 10% hydrogen peroxide in growth inhibition of P. expansum in the agar diffusion assay was total, and its MIC as determined by the agar and broth dilution assays was less than 0.025%. These results indicate that the application of small quantities of hydrogen peroxide to the apple skin might be an alternative to fungicides in the elimination of P. expansum.

CAS agar diffusion assay for the measurement of siderophores in biological fluids

2001 ◽  
Vol 44 (1) ◽  
pp. 89-95 ◽  
Author(s):  
Sung Heui Shin ◽  
Yong Lim ◽  
Shee Eun Lee ◽  
Nam Woong Yang ◽  
Joon Haeng Rhee
Keyword(s):  
Biological Fluids ◽  
Agar Diffusion ◽  
Agar Diffusion Assay ◽  
Diffusion Assay

scholarly journals Colistin and Isavuconazole Interact Synergistically In Vitro against Aspergillus nidulans and Aspergillus niger

2020 ◽  
Vol 8 (9) ◽  
pp. 1447
Author(s):  
Patrick Schwarz ◽  
Elie Djenontin ◽  
Eric Dannaoui
Keyword(s):  
Aspergillus Niger ◽  
Aspergillus Nidulans ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Important Species ◽  
Agar Diffusion ◽  
Agar Diffusion Assay ◽  
Diffusion Assay

The in vitro interactions of isavuconazole in combination with colistin were evaluated against 55 clinical Aspergillus species isolates belonging to the five most important species (Aspergillus flavus, Aspergillus fumigatus, Aspergillus nidulans, Aspergillus niger, and Aspergillus terreus) responsible for human aspergillosis by a microdilution checkerboard technique based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) reference method for antifungal susceptibility testing. Selected isolates (A. nidulans, n = 10; A. niger, n = 15) were additionally evaluated by an agar diffusion assay using isavuconazole gradient concentration strips with or without colistin incorporated Roswell Parc Memorial Institute (RPMI) agar. Interpretation of the checkerboard results was done by the fractional inhibitory concentration index. Using the checkerboard method, combination isavuconazole–colistin was synergistic for 100% of the 15 A. nidulans isolates and for 60% of the 20 A. niger isolates. No interactions were found for any of the other isolates. By agar diffusion assay, minimal inhibitory concentrations (MICs) in combination decreased compared to isavuconazole alone for 92% of the isolates. No interactions were found for any A. nidulans isolates, but synergy was observed for 40% of the A. niger isolates. A poor essential agreement of EUCAST and gradient concentration strip MICs at ± 2 log2 dilutions with 0% was obtained. Antagonistic interactions were never observed regardless of the technique used.

scholarly journals Characterization and Antimicrobial Activities of a Metabolite from a New Streptomyces Species from Bangladeshi Soil

2009 ◽  
Vol 2 (1) ◽  
pp. 178-185
Author(s):  
M. Akhand ◽  
M. A. A. Al-Bari ◽  
M. A. Islam ◽  
Proma Khondkar
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Activities ◽  
Assay Method ◽  
Streptomyces Species ◽  
Isolation And Characterization ◽  
Test Organisms ◽  
Actinomycete Strain ◽  
Diffusion Assay ◽  
Strong Antimicrobial Activity

A new actinomycete strain was isolated from Western part of Bangladesh and identified as a new Streptomyces species on the basis of its morphological, biochemical, cultural characteristics and 16S rRNA data. The present paper describes the isolation and characterization of compound 1 from this new Streptomyces species with the help of various chemical and spectroscopic methods. Antimicrobial activity of compound 1 was tested by disc diffusion assay method and compared with that of standard antibiotics (Kanamycin for antibacterial activity and Nystatin for antifungal activity). The compound has been found to exhibit moderate to strong antimicrobial activity against the test organisms. Cytotoxicity of the compound 1 and the pet. ether extract of Czapek Dox (alkaline) broth of Streptomyces species was evaluated in brine shrimp bioassay with LC50 values of 23.85 µg/ml (ppm) and 19.95 µg/ml (ppm), respectively. Keywords: Streptomyces; Antimicrobial activity; Cytotoxicity. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i1.3079                  J. Sci. Res. 2 (1), 178-185 (2010)  

Quantitative determination of antibiotics by automated six-point parallel-line agar diffusion assay

1974 ◽  
Vol 40 (4) ◽  
pp. 610-611 ◽  
Author(s):  
D. A. Detmar ◽  
K. H. F. van Hemert ◽  
R. Malherbe ◽  
J. G. Oostendorp
Keyword(s):  
Quantitative Determination ◽  
Parallel Line ◽  
Agar Diffusion ◽  
Agar Diffusion Assay ◽  
Diffusion Assay
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