Search results for "AGENTS"
showing 10 items of 7330 documents
DNA interaction of new copper(II) complexes with sulfonamides as ligands
2007
New copper(II) complexes with sulfonamide ligands have been prepared and characterized. Sulfonamide ligands were prepared through a reaction between 8-aminoquinoline and either 2-mesitylene (Hqmesa), 4-tert-butylbenzene (Hqtbsa), or alpha-toluene (Halphaqtsa) sulfonyl chlorides. The structural analysis carried out for complex [Cu(alphaqtsa)(2)] indicated that the local environment of the Cu(II) cation is between a square planar and a tetrahedral geometry, with stacking of the benzene rings of the sulfonyl ligands between neighbor molecules. Powder EPR spectra at room temperature gave rhombic spectra for the [Cu(alphaqtsa)(2)] and [Cu(qmesa)(2)] complexes and an axial spectrum for the [Cu(qt…
Pyrrolidine in Drug Discovery: A Versatile Scaffold for Novel Biologically Active Compounds
2021
AbstractThe five-membered pyrrolidine ring is one of the nitrogen heterocycles used widely by medicinal chemists to obtain compounds for the treatment of human diseases. The great interest in this saturated scaffold is enhanced by (1) the possibility to efficiently explore the pharmacophore space due to sp3-hybridization, (2) the contribution to the stereochemistry of the molecule, (3) and the increased three-dimensional (3D) coverage due to the non-planarity of the ring—a phenomenon called “pseudorotation”. In this review, we report bioactive molecules with target selectivity characterized by the pyrrolidine ring and its derivatives, including pyrrolizines, pyrrolidine-2-one, pyrrolidine-2…
Role of hydrophobicity on the monoamine receptor binding affinities of central nervous system drugs: a quantitative retention-activity relationships …
2004
Abstract Biological action and activity reflect an aspect of the fundamental physicochemical properties of the bioactive compounds. As an alternative to classical QSAR studies, in this work different quantitative retention–activity relationships (QRAR) models are proposed, which are able to describe the role of hydrophobicity on the binding affinity to different brain monoamine receptors (H 1 -histamine, α 1 -noradrenergic and 5-HT 2 -serotonergic) of different families of psychotherapeutic drugs. The retention of compounds is measured in a biopartitioning micellar chromatography (BMC) system using Brij-35 mobile phases. The adequacy of the QRAR models developed is due to the fact that both…
Mononuclear rearrangement of heterocycles in zwitterionic micelles of amine oxide surfactants.
2012
Abstract Rate constants for the mononuclear rearrangement (MRH) of Z -phenylhydrazones of some 5-substituted-3-benzoyl-1,2,4-oxadiazoles in water have been measured in the presence of zwitterionic micelles. The use of micellized N -tetradecyl- N , N -dimethylamineoxide (C 14 DMAO) as the reaction medium allowed to solubilize the otherwise water-insoluble oxadiazoles. Micellar rate effects were analyzed by using a simple pseudo-phase model and compared with those obtained in non-ionic micelles (Triton X-100). Evidence that both the rate of the rearrangement reaction and the binding of the substrates to the micelles are mainly governed by substrate hydrophobicity is obtained. The disagreement…
Effects of Hypericum Extract on the Expression of Serotonin Receptors
1994
The influence of hypericum extract LI 160 on the expression of serotonin receptors was investigated using a neuroblastoma cell line to establish a model for the regulation of neurotransmitters by immunologically active compounds such as cytokines. The cells were incubated with hypericum extract LI 160 in kinetic form for 2, 4, 6, 8, and 10 hours, then washed. The serotonin receptor expression analysis was compared to that of a placebo control solution. The neuroblastoma cells showed a clearly reduced expression of the serotonin receptors under treatment with hypericum extract. First stimulation experiments with interleukin-1 (IL-1) and hypericum extract suggest that a further reduction of …
Oral microbiome and systemic antineoplastics in cancer treatment:a systematic review
2021
Oral mucositis is one of the most common side effects in cancer patients receiving systemic antineoplastics. However, the underlying biological mechanisms leading to this condition are still unclear. For this reason, it has been hypothesised that systemic antineoplastics may cause an imbalance on the oral microbiota that subsequently triggers oral mucosa damage. A systematic review was performed following the PRISMA protocol and the PICO question established was: patients diagnosed with cancer, who are candidates for receiving systemic antineoplastics (P=Patients), that undergo oral microbiome determinations (I=Intervention), before and after systemic antineoplastics administration (C=Compa…
Effect of crosslinking strategy on the biological, antibacterial and physicochemical performance of hyaluronic acid and ɛ-polylysine based hydrogels
2022
The design of multifunctional hydrogels based on bioactive hyaluronic acid (HA) and antibacterial cationic polymer ε-poly-L-lysine (ε-PL) is a promising tool in tissue engineering applications. In the current study, we have designed hyaluronic acid and ε-polylysine composite hydrogel systems with antibacterial and cell attractive properties. Two distinct crosslinking approaches were used: the physical crosslinking based on electrostatic at- tractions and the chemical crosslinking of charged functional groups (-NH2 and -COOH). The impact of the crosslinking strategy on fabricated hydrogel molecular structure, swelling behavior, gel fraction, morphology, porosity, visc…
To Hit or Not to Hit, That Is the Question - Genome-wide Structure-Based Druggability Predictions for Pseudomonas aeruginosa Proteins.
2015
Pseudomonas aeruginosa is a Gram-negative bacterium known to cause opportunistic infections in immune-compromised or immunosuppressed individuals that often prove fatal. New drugs to combat this organism are therefore sought after. To this end, we subjected the gene products of predicted perturbative genes to structure-based druggability predictions using DrugPred. Making this approach suitable for large-scale predictions required the introduction of new methods for calculation of descriptors, development of a workflow to identify suitable pockets in homologous proteins and establishment of criteria to obtain valid druggability predictions based on homologs. We were able to identify 29 pert…
Hypoxia-Selective Dissociation Mechanism of a Nitroimidazole Nucleoside in a DNA Environment
2019
Photodynamic therapy is a promising approach to treat a variety of superficial tumors and other diseases. One of its major limitations arises from its dependence on molecular oxygen, which decreases the efficiency of the therapy in hypoxia conditions commonly developed by solid tumors. The present contribution reveals the molecular mechanism of a modified thymine bearing a nitroimidazole substituent, a photosensitizer able to produce highly harmful interstrand cross-links in the DNA double strand after irradiation selectively in absence of oxygen. The mechanism is resolved at a fully atomistic and electronic level relying on quantum mechanics (CASPT2, coupled-cluster, DFT, and TD-DFT method…
Hydrogels for potential colon drug release by thiol-ene conjugate addition of a new inulin derivative.
2008
Inulin was chosen as a starting polymer for biocompatible, pH-sensitive and biodegradable hydrogels. Three INUDVSA-TT hydrogels were obtained by crosslinking inulin derivatives with trimethylolpropane tris(3-mercaptopropionate) under varying conditions. The resulting hydrogels were cell compatible, as demonstrated by MTS and trypan blue exclusion assays acting on Caco-2 cells, and were biodegraded by inulinase and esterase, thus suggesting their use as colonic drug delivery systems. 2-Methoxyestradiol, an anti-cancer drug, was soaked in INUDVSA-TT hydrogels and its in vitro release and apoptotic effect on Caco-2 cells were evaluated.