Search results for "ntimicrobial"
showing 10 items of 708 documents
Retention behaviour of paracelsin peptides on reversed-phase silicas with varying n-alkyl chain length and ligand density.
1989
As part of further investigations on the characterization of the ligand-induced conformational stabilization of peptides, two series of n-alkyldimethylsilyl bonded silicas have been prepared. In series A the n-alkyl chain length, n, of the bonded phase was varied between 1 and 20 carbon atoms at a constant ligand density. In series B the ligand density, alpha exp, was gradually changed from 0 to 4.1 mumol/m2 on a C1, C4, C6, C8 and C18 bonded phase. The retention behaviour of four peptides of the paracelsin family were examined under isocratic conditions, using a ternary mobile phase of water-methanol-acetonitrile (22:39:39, v/v/v). Plots of k' versus n showed pronounced maxima between n = …
Impact of ultrasound-assisted extraction and solvent composition on bioactive compounds and in vitro biological activities of thyme and rosemary
2020
Mediterranean herbs, specially thyme and rosemary, are important ingredients in food preparation and more recently have been studied as natural sources of bioactive compounds. This study aimed to study the effect of matrix (thyme vs. rosemary), and extraction protocol (conventional extraction vs. ultrasound assisted extraction) solvent composition (water vs. 50:50 ethanol:water solution) on the extraction of high value compounds (phenolic compounds, flavonoids and carotenoids) and also explore the antioxidant, antimicrobial (Listeria innocua, Staphylococcus aureus, and Salmonella enterica), probiotic (Lactobacillus casei and Bifidobacterium lactis), and anti-inflammatory activities. The phe…
Activity of Antimicrobial Silver Polystyrene Nanocomposites.
2012
A simple technique based on doping polymers within situgenerated silver nanoparticles (Ag/PS films) has been developed. In particular, an antiseptic material has been prepared by dissolving silver 1,5-cyclooctadiene-hexafluoroacetylacetonate in amorphous polystyrene, and the obtained solid solution has been heated for ca. 10 s at a convenient temperature (180°C). Under such conditions the metal precursor decomposes producing silver atoms that diffuse into the polymer and clusterize. The antimicrobial characteristics of the resulting polystyrene-based material have been accurately evaluated towardEscherichia coli (E. coli)comparing the cytotoxicity effect of 10 wt.% and 30 wt.% (drastic and …
Antibacterial chitosan-based blends with ethylene–vinyl alcohol copolymer
2010
Abstract This study reports for the first time about the formulation, morphology, water barrier and the antimicrobial activity of high and low molecular weight chitosonium-acetate based solvent-cast blends with ethylene–vinyl alcohol (EVOH) copolymers. The blends based on the low molecular weight chitosan grade showed enhanced phase morphology, transparency, enhanced water barrier properties, up to 86% water permeability reduction compared to pure chitosonium-acetate films, as well as excellent antimicrobial activity. When the fraction of low molecular weight chitosan exceeded the phase inversion in the blend, phase segregation became noticeable but good interfacial adhesion was still obser…
Orientation and Dynamics of Peptides in Membranes Calculated from 2H-NMR Data
2009
Solid-state (2)H-NMR is routinely used to determine the alignment of membrane-bound peptides. Here we demonstrate that it can also provide a quantitative measure of the fluctuations around the distinct molecular axes. Using several dynamic models with increasing complexity, we reanalyzed published (2)H-NMR data on two representative alpha-helical peptides: 1), the amphiphilic antimicrobial peptide PGLa, which permeabilizes membranes by going from a monomeric surface-bound to a dimeric tilted state and finally inserting as an oligomeric pore; and 2), the hydrophobic WALP23, which is a typical transmembrane segment, although previous analysis had yielded helix tilt angles much smaller than ex…
Insect Immunity
2001
Two novel antimicrobial peptides, which we propose to name termicin and spinigerin, have been isolated from the fungus-growing termite Pseudacanthotermes spiniger (heterometabole insect, Isoptera). Termicin is a 36-amino acid residue antifungal peptide, with six cysteines arranged in a disulfide array similar to that of insect defensins. In contrast to most insect defensins, termicin is C-terminally amidated. Spinigerin consists of 25 amino acids and is devoid of cysteines. It is active against bacteria and fungi. Termicin and spinigerin show no obvious sequence similarities with other peptides. Termicin is constitutively present in hemocyte granules and in salivary glands. The presence of …
Fragments of β-thymosin from the sea urchinParacentrotus lividusas potential antimicrobial peptides against staphylococcal biofilms
2012
The immune mediators in echinoderms can be a potential source of novel antimicrobial peptides (AMPs) applied toward controlling pathogenic staphylococcal biofilms that are intrinsically resistant to conventional antibiotics. The peptide fraction <5 kDa from the cytosol of coelomocytes of the sea urchin Paracentrotus lividus (5-CC) was tested against a group of Gram-positive and Gram-negative pathogen reference strains. The 5-CC of P. lividus was active against all planktonic-tested strains but also showed antibiofilm properties against staphylococcal strains. Additionally, we demonstrated the presence of three small peptides in the 5-CC belonging to segment 9-41 of a P. lividusβ-thymosin. T…
(+)-(E)-Chrysanthenyl Acetate: A Molecule with Interesting Biological Properties Contained in the Anthemis secundiramea (Asteraceae) Flowers
2020
Anthemis secundiramea is a perennial herb native widespread throughout the Mediterranean basin. The oil obtained from the flowers of this plant has antimicrobial properties against gram-positive and -negative bacteria, and inhibits the biofilm formation. The extract of A. secundiramea also has antioxidant activity&mdash
Chemical composition, antimicrobial and antioxidant activities of the essential oil of Italian Prangos trifida (Mill.) Herrnst. & Heyn
2022
In this work, the essential oil of the aerial parts of a not previously investigated accession of Prangos trifida (Mill.) Herrnst. & Heyn (Apiaceae), collected in Northern Italy, was analysed by GC/MS. Twenty-five compounds were identified, accounting for 91.30% of the total oil, which is characterised by a high content of monoterpene hydrocarbons (71.26%). The main constituents of the essential oil were cis-beta-ocimene (18.12%), alpha-phellandrene (12.14%), sylvestrene (11.32%), p-mentha-1,3,8-triene (9.56%) and alpha-pinene (8.85%). The essential oil of P. trifida showed a good antimicrobial activity directed above all against Gram-positive bacteria, and had an interesting antioxidan…
Dihydrophenanthrenes from a Sicilian Accession of Himantoglossum robertianum (Loisel.) P. Delforge Showed Antioxidant, Antimicrobial, and Antiprolife…
2021
The peculiar aspect that emerges from the study of Orchidaceae is the presence of various molecules, which are particularly interesting for pharmaceutical chemistry due to their wide range of biological resources. The aim of our study was to investigate the properties of two dihydrophenanthrenes, isolated, for the first time, from Himantoglossum robertianum (Loisel.) P. Delforge (Orchidaceae) bulbs and roots. Chemical and spectroscopic study of the bulbs and roots of Himantoglossumrobertianum (Loisel.) P. Delforge resulted in the isolation of two known dihydrophenanthrenes—loroglossol and hircinol—never isolated from this plant species. The structures were evaluated based on 1H-NMR, 13C-NMR…