Search results for "sensitivity [detector]"
showing 10 items of 400 documents
Isolation and identification of the antibacterial compounds from Helichrysum stoechas.
1991
Fractionation of the dicholoromethane extract of the aerial parts of Helichrysum stoechas yielded seven isolates (1-7), which exhibited varying antimicrobial activity against Gram-positive bacteria. Pure compounds 1-3 have been previously reported in the same species and 4 and 5 were identified as italipyrone and plicatipyrone, previously isolated from H. italicum and H. plicatum. The two other isolates are helipyrone (6) and homoarenol (7) mixed with related substances. Compound 6c (4,4'-dihydroxy-5,6,5',6'-tetramethyl-3,3'-methylen-di-pyr-2-one) and 6b helipyrone with one methyl substitution, have not been previously reported in other species.
New agents active against Mycobacterium avium complex selected by molecular topology: a virtual screening method
2003
Objectives: In order to select new drugs and to predict their in vitro activity against Mycobacterium avium complex (MAC), new quantitative structure-activity relationship (QSAR) models were developed. Methods: The activities against MAC of 29 structurally heterogeneous drugs were examined by means of linear discriminant analysis (LDA) and multilinear regression analysis (MLRA) by using topological indices (TI) as structural descriptors. In vitro antimycobacterial activities were determined by a broth microdilution method with 7H9 medium. Results: The topological model obtained successfully classifies over 80% of compounds as active or inactive; consequently, it was applied in the search fo…
Antibacterial activity of flavonoids and phenylpropanoids from Marrubium globosum ssp. libanoticum.
2006
Marrubium globosum Montbr. et Auch. ex Benth. ssp. libanoticum Boiss. (Lamiaceae) is a medicinal plant used for the treatment of inflammatory diseases, asthma, coughs and other pulmonary and urinary problems. The goal of our study was to assess the biological activity of M. globosum testing the methanol extract of aerial parts for its antibacterial activity against bacteria known to cause respiratory, gastrointestinal, skin and urinary disorders; the extract showed antibacterial effects against all the strains of bacteria used. A purification of this active extract showed the presence, as main constituents, of verbascoside, isorhamnetin 3-O-beta-D-rutinoside, quercetin 3-O-beta-D-rutinoside…
Synthesis and anti-staphylococcal activity of new 4-diazopyrazole derivatives.
2012
Abstract Several new 4-diazopyrazole derivatives 6a – g and 9a – c were obtained by the reaction of 1-(R-substituted-phenyl)-3-(1,3-dimethyl-1 H -pyrazol-5-yl)ureas 5a – g and N -(1,3-dimethyl-1 H -pyrazol-5-yl)-2-(R-substituted-phenyl)acetamides 8a – c respectively with a sevenfold excess of nitrous acid in acetic acid solution. The compounds were assayed for their activity against the Staphylococcus aureus reference strains ATCC 25923, ATCC 29213 and ATCC 6538, as well as six veterinary strains. The best anti-staphylococcal profile was showed by [(R-substituted-phenyl)acetyl](4-diazonio-1,3-dimethyl-1 H -pyrazol-5-yl)azanides 9a , c . Compound 9c was also able at 3.1 μg mL −1 to inhibit o…
Prediction of Aquatic Toxicity of Benzene Derivatives to Tetrahymena pyriformis According to OECD Principles
2016
Background: Many QSAR studies have been developed to predict acute toxicity over several biomarkers like Pimephales promelas, Daphnia magna and Tetrahymena pyriformis. Regardless of the progress made in this field there are still some gaps to be resolved such as the prediction of aquatic toxicity over the protozoan T. pyriformis still lack a QSAR study focused in accomplish the OECD principles. Methods: Atom-based quadratic indices are used to obtain quantitative structure-activity relationship (QSAR) models for the prediction of aquatic toxicity. Our models agree with the principles required by the OECD for QSAR models to regulatory purposes. The database employed consists of 392 substitut…
Inhibitors of antibiotic resistance mechanisms: clinical applications and future perspectives
2020
Bacterial strains responsible for antibiotic resistant infections are increasing in an alarming way and the evolution of resistance mechanisms seems to be unstoppable. In the past decade, many efforts have been made in order to counteract this phenomenon but very few compounds have reached clinical trials. The development of new classes of antibiotics able to overcome the main bacterial drug resistance mechanisms is urgently required to counter the imminent danger of a postantibiotic era.
Pectin: A Long-Neglected Broad-Spectrum Antibacterial.
2020
First reported in the late 1930s and first partly explained in 1970, the antibacterial activity of pectin remained almost ignored until the late 1990s. The concomitant emergence of research on natural antibacterials and on new usages of pectin polysaccharides, including those in medicine widely researched in Russia, has led to a renaissance of research in the physiological properties of this uniquely versatile polysaccharide ubiquitous in plants and fruits. Collecting scattered information, this study provides an updated overview on the subtle factors affecting the behaviour of pectin as antimicrobial. Less degraded pectin extracted via acid-free routes, we argue in the conclusions, will so…
Isolation and partial characterization of antagonistic peptides produced by Paenibacillus sp. strain B2 isolated from the sorghum mycorrhizosphere.
2005
ABSTRACT Paenibacillus sp. strain B2, isolated from the mycorrhizosphere of sorghum colonized by Glomus mosseae , produces an antagonistic factor. This factor has a broad spectrum of activity against gram-positive and gram-negative bacteria and also against fungi. The antagonistic factor was isolated from the bacterial culture medium and purified by cation-exchange, reverse-phase, and size exclusion chromatography. The purified factor could be separated into three active compounds following characterization by amino acid analysis and by combined reverse-phase chromatography and mass spectrometry (liquid chromatography-mass spectrometry and mass spectrometry-mass spectrometry). The first com…
Oxidative stress and mitochondrial dysfunction in Kindler syndrome
2014
This is an Open Access article distributed under the terms of the Creative Commons Attribution License.-- et al.
Antilisterial peptides from Spanish dry-cured hams: Purification and identification.
2016
The typical Spanish dry-cured ham has a particular sensory quality that makes it a distinctive food, highly appreciated for consumers worldwide. Its particular physicochemical properties, such as high salt content and reduced water activity contribute to their shelf-stability. However, post-processing actions carried out for the commercialization of these products such as slicing may increase the risk of development of pathogenic microorganisms as Listeria monocytogenes. During ripening, muscle proteins are hydrolyzed by muscle peptidases releasing peptides and free amino acids. Some of these peptides have been described to exert biological activities such as antioxidant and ACE-inhibition.…