Search results for "Activity"
showing 10 items of 7178 documents
Quantum correlations in generalized spin star system
2006
The problem of detecting quantum signatures in the correlations formed in dynamical evolution of quantum bipartite systems receives a lot of attention in current literature. Generally speaking, the occurrence of correlations between two observables of a system does not necessarily reflect nonclassical behaviour. In this paper, the exact dynamics of a pair of uncoupled spins 1/2 interacting with a common spin 1/2 bath is investigated. Starting from a separable initial condition, the ability of the system to develop purely quantum correlations is brought to light. Physical interpretation of the concurrence function as well as a suggestion on how to measure it are given.
Antibacterial Activity of Flavonoids Against Methicillin-resistant Staphylococcus aureus strains
2000
An experimental and theoretical study was performed on the anti-staphylococcal activity of 18 natural and synthetic flavonoids against methicillin-resistant Staphylococcus aureus strains. The analysed flavonoids belong to three well-differentiated structural patterns: chalcones, flavanones and flavones. The quantitative analysis of the anti-staphylococcal activity of the compounds was carried out by determining their percent inhibition degree. The hierarchical cluster analysis method was used to analyse the anti-MRSA activity of the compounds. With this methodology, the flavonoids were classified into four groups according to their anti-staphylococcal activity (high, sufficient, intermediat…
Effect of Cyanato, Azido, Carboxylato, and Carbonato Ligands on the Formation of Cobalt(II) Polyoxometalates: Characterization, Magnetic, and Electro…
2007
Five Co(II) silicotungstate complexes are reported. The centrosymmetric heptanuclear compound K(20)[{(B-beta-SiW(9)O(33)(OH))(beta-SiW(8)O(29)(OH)(2))Co(3)(H(2)O)}(2)Co(H(2)O)(2)]47 H(2)O (1) consists of two {(B-beta-SiW(9)O(33)(OH))(beta-SiW(8)O(29)(OH)(2))Co(3)(H(2)O)} units connected by a {CoO(4)(H(2)O)(2)} group. In the chiral species K(7)[Co(1.5)(H(2)O)(7))][(gamma-SiW(10)O(36))(beta-SiW(8)O(30)(OH))Co(4)(OH)(H(2)O)(7)]36 H(2)O (2), a {gamma-SiW(10)O(36)} and a {beta-SiW(8)O(30)(OH)} unit enclose a mononuclear {CoO(4)(H(2)O)(2)} group and a {Co(3)O(7)(OH)(H(2)O)(5)} fragment. The two trinuclear Co(II) clusters present in 1 enclose a mu(4)-O atom, while in 2 a mu(3)-OH bridging group co…
Acylated oleanane-type saponins from Ganophyllum giganteum
2014
Abstract Five oleanane-type saponins , 3- O -β- D -glucuronopyranosylzanhic acid 28- O -β- D -xylopyranosyl-(1→3)-[α- L -rhamnopyranosyl-(1→2)]-(4- O -acetyl)-β- D -fucopyranosyl ester ( 1 ), 3- O -β- D -glucopyranosylzanhic acid 28- O -β- D -xylopyranosyl-(1→3)-[α- L -rhamnopyranosyl-(1→2)]-(4- O -acetyl)-β- D -fucopyranosyl ester ( 2 ), zanhic acid 28- O -β- D -xylopyranosyl-(1→3)-[α- L -rhamnopyranosyl-(1→2)]-(4- O -acetyl)-β- D -fucopyranosyl ester ( 3 ), zanhic acid 28- O -α- L -rhamnopyranosyl-(1→2)-4- O -[(3′-hydroxy-2′-methyl-butyroyloxy)-3-hydroxy-2-methyl-butyroyloxy]-β- D -fucopyranosyl ester ( 4 ), medicagenic acid 28- O -α- L -rhamnopyranosyl-(1→2)-4- O -[(3′-hydroxy-2′-methyl-…
Novel Acylated Triterpene Glycosides from Muraltia heisteria
2002
Four new acylated triterpene glycosides (1-4) have been isolated as two inseparable mixtures of the trans- and cis-3,4,5-trimethoxycinnamoyl derivatives (1,2 and 3,4) from the roots of Muraltia heisteria. The structures of these compounds were elucidated by various 1D and 2D NMR techniques, including (1)H and (13)C, COSY, NOESY, HSQC, TOCSY, and HMBC experiments and FABMS. Compounds 3 and 4 were shown to be cytotoxic in a human colon cancer cell line but did not show any ability to potentiate in vitro cisplatin cytotoxicity.
Synthesis and biological evaluation of 2- and 3-aminobenzo[b]thiophene derivatives as antimitotic agents and inhibitors of tubulin polymerization.
2007
Two new series of inhibitors of tubulin polymerization based on the 2-amino-3-(3,4,5-trimethoxybenzoyl)benzo[b]thiophene molecular skeleton and its 3-amino positional isomer were synthesized and evaluated for antiproliferative activity, inhibition of tubulin polymerization, and cell cycle effects. Although many more 3-amino derivatives have been synthesized so far, the most promising compound in this series was 2-amino-6-methyl-3-(3,4,5-trimethoxybenzoyl)benzo[b]thiophene, which inhibits cancer cell growth at subnanomolar concentrations and interacts strongly with tubulin by binding to the colchicine site.
Semisynthesis of antitumoral acetogenins: SAR of functionalized alkyl-chain bis-tetrahydrofuranic acetogenins, specific inhibitors of mitochondrial c…
2000
The acetogenins of Annonaceae are known by their potent cytotoxic activity. In fact, they are promising candidates as a new future generation of antitumoral drugs to fight against the current chemiotherapic resistant tumors. The main target enzyme of these compounds is complex I (NADH:ubiquinone oxidoreductase) of the mitochondrial respiratory chain, a key enzymatic complex of energy metabolism. In an attempt to characterize the relevant structural factor of the acetogenins that determines the inhibitory potency against this enzyme, we have prepared a series of bis-tetrahydrofuranic acetogenins with different functional groups along the alkyl chain. They comprise several oxo, hydroxylimino,…
N-Heterocyclic choline analogues based on 1,2,3,4-tetrahydro(iso)quinoline scaffold with anticancer and anti-infective dual action
2016
Pharmacological effects of biologically active “small molecules” can be improved by their targeted modification, which affects drug delivery and interaction with tumor cells and microorganisms. We aimed to evaluate anticancer and antimicrobial activity of lipid-like choline derivatives modified via simultaneous introduction of tetrahydro(iso)quinoline based pharmacophore system at nitrogen atom and long chain alkyl substituent at oxygen atom. Target compounds were synthesized under phase-transfer catalysis conditions followed by quaternization, and evaluated for cytotoxicity and NO-generation ability on HT-1080 and MG-22A tumor cell lines and NIH 3T3 normal mouse fibroblasts, and screened f…
The effects of structural changes on the anti-microbial and anti-proliferative activities of diimidazolium salts
2017
An array of diimidazolium salts has been synthesized and used to investigate their anti-microbial and anti-proliferative activities. In particular, salts based on the 3,30-di-n-alkyl-1,10-(1,n-phenylenedimethylene)- diimidazolium cation and differing in the alkyl chain length on the imidazolium ion, the isomeric substitution on the aromatic spacer and in the anion nature were used. The anti-proliferative activity was evaluated against cervical (HeLa), colon adenocarcinoma (HT-29) and breast (SKBR3) cancer cell lines. In the latter case, also a morphological assessment after treatment with salts was performed. All salts were tested for their hemolytic activity against human erythrocytes. On …
Sulphonamide Antifolates Inhibiting Thymidylate Synthase. Synthesis, Enzyme Inhibition and Cytotoxicity
1993
Synthesis and biological evaluation are described of seven new analogues (3-9) of two potent thymidylate synthase inhibitors, 10-propargyl-5,8-dideazafolate (1) and its 2-methyl-2-deamino congener ICI 198583 (2). While the new compunds 3 and 4 were analogues of 1 and 2, respectively, containing a p-aminobenzenesulfonyl residue in place of the p-aminobenzoic acid residue, the remaining 5 new compounds were analogues of 4 with the L-glutamic acid residue replaced by glycine (5), L-valine (6), L-alanine (7), L-phenylglycine (8) or L-norvaline (9). The new analogues were tested as inhibitors of thymidylate synthases isolated from tumour (Ehrlich carcinoma), parasite (Hymenolepis diminuta) and n…