Search results for "derivati"
showing 10 items of 1360 documents
Unprecedented new nonadecylpara-hydroperoxycinnamate isolated fromErythrina excelsaand its cytotoxic activity
2014
A new unprecedented cinnamate derivative (1) was obtained from Erythrina excelsa (Leguminosae) and identified as nonadecyl para-hydroperoxycinnamate. This compound was isolated together with three known compounds, namely lupeol (2), mixture of sitosterol and stigmasterol (3), and isoneorautenol (4). Their structures were established on the basis of NMR and mass spectroscopic data in conjunction with those reported in the literature. Compound 1 was evaluated for its capability of inhibiting cancer cell lines and growth of a panel of microbial strains. It turned out that 1 is moderately to significantly cytotoxic against six cancer cell lines and shows weak to no antimicrobial activity.
A new depsidone derivative from mangrove sediment derived fungus
2018
A new depsidone derivative botryorhodine I (1), along with eight known compounds (2-9) were obtained from solid rice cultures of the fungal strain, Lasiodiplodia theobromae M4.2-2 isolated from a mangrove sediment sample. The structures of the isolated compounds were elucidated on the basis of 1 D and 2 D NMR analysis as well as by HRESIMS. All compounds were evaluated for their cytotoxic potential against the mouse lymphoma cell line L5178Y as well as for their antibacterial activities against a panel of Gram-positive and Gram-negative bacterial strains. Compound 3 revealed potent cytotoxic activity with an IC50 of 7.3 µM whereas compound 7 showed selective anti-bacterial activity against …
Self-assembling and auto-crosslinkable hyaluronic acid hydrogels with a fibrillar structure
2008
Abstract A hyaluronic acid derivative bearing pendant l -benzoyl-cysteine portions (with a derivatization degree equal to 10 mol.%) was synthesized by linking N,N′-dibenzoyl- l -cystine to the polysaccharide and then reducing its disulfide bridge to thiol groups. The formation of π–π stacking interactions between the benzoyl moieties was studied by fluorescence spectroscopy as a function of polymer concentration and oxidation time. The efficiency of oxidation of thiol groups to disulfide bridges occurring in phosphate buffer pH 7.4, was determined by colorimetric assays. The hydrogel formed by means of oxidative crosslinking has shown the presence of fibrillar aggregates as detected by ligh…
Temporally precise control of single-neuron spiking by juxtacellular nanostimulation
2017
Temporal patterns of action potentials influence a variety of activity-dependent intra- and intercellular processes and play an important role in theories of neural coding. Elucidating the mechanisms underlying these phenomena requires imposing spike trains with precisely defined patterns, but this has been challenging due to the limitations of existing stimulation techniques. Here we present a new nanostimulation method providing control over the action potential output of individual cortical neurons. Spikes are elicited through the juxtacellular application of short-duration fluctuating currents (“kurzpulses”), allowing for the sub-millisecond precise and reproducible induction of arbitr…
Effects of DA-Phen, a dopamine-aminoacidic conjugate, on alcohol intake and forced abstinence
2016
The mesolimbic dopamine (DA) system plays a key role in drug reinforcement and is involved in the development of alcohol addiction. Manipulation of the DAergic system represents a promising strategy to control drug-seeking behavior. Previous studies on 2-amino-N-[2-(3,4-dihydroxy-phenyl)-ethyl]-3-phenyl-propionamide (DA-Phen) showed in vivo effects as a DA-ergic modulator. This study was aimed at investigate DA-Phen effects on operant behavior for alcohol seeking behavior, during reinstatement following subsequent periods of alcohol deprivation. For this purpose, male Wistar rats were tested in an operant paradigm of self-administration; behavioral reactivity and anxiety like-behavior durin…
Comparative Study of the Effects Exerted by N-Valproyl-L-Phenylalanine and N-valproyl-L-tryptophan on CA1 Hippocampal Epileptiform Activity in Rat
2018
Background: The research on the improvement of epilepsy therapy is constantly growing. Valproyl-LPhenylalanine (VPA-Phen) and N-valproyl-L-tryptophan (VPA-Tryp) were synthesized to increase the antiepileptic efficacy of valproic acid. Methods: VPA-Phen and VPA-Tryp were comparatively tested on CA1 hippocampal epileptiform bursting activity obtained by increasing potassium and lowering calcium and magnesium concentrations in the fluid perfusing rat brain slices. Each slice was treated with a single concentration (0.2, 0.5, 1 mM) of VPA-Phen or VPA-Tryp. Both burst duration and interburst frequency, during and after treatment, were off-line compared with baseline values. For both parameters,…
Combination Therapy with Oral Treprostinil for Pulmonary Arterial Hypertension:A Double-Blind Placebo-controlled Clinical Trial
2020
Rationale: Oral treprostinil improves exercise capacity in patients with pulmonary arterial hypertension (PAH), but the effect on clinical outcomes was unknown.\ud \ud Objectives: To evaluate the effect of oral treprostinil compared with placebo on time to first adjudicated clinical worsening event in participants with PAH who recently began approved oral monotherapy.\ud \ud Methods: In this event-driven, double-blind study, we randomly allocated 690 participants (1:1 ratio) with PAH to receive placebo or oral treprostinil extended-release tablets three times daily. Eligible participants were using approved oral monotherapy for over 30 days before randomization and had a 6-minute-walk dista…
Fluorinated and pegylated polyaspartamide derivatives to increase solubility and efficacy of Flutamide
2012
New fluorinated amphiphilic copolymers based on a biocompatible polyaspartamide have been prepared in order to obtain polymeric micelles useful for delivering anticancer drugs. In particular, α,β-poly(N-2-hydroxyethyl)-d,l-aspartamide (PHEA) has been derivatized with polyethylene glycol (PEG(2000)) and ethylendiamine (EDA). Both these portions form the hydrophilic part of the copolymer, while the hydrophobic moiety is given by 1,2,4-oxadiazoles: 5-pentafluorophenyl-3-perfluoroheptyl-1,2,4-oxadiazole (PPOX) or 3-carboxyethyl-5-pentadecafluoroheptyl-1,2,4-oxadiazole (CPOX). Copolymers named PHEA-PEG(2000)-EDA-PPOX and PHEA-PEG(2000)-EDA-CPOX have been prepared with various degrees of derivati…
Antioxidant Profile of Mono-and Dihydroxylated Flavone Derivatives in Free Radical Generating Systems
1995
Abstract A number of free radical generating systems were used to investigate the antioxidant properties and structure-activity relationships of a series of monohydroxylated and dihydroxylated flavones. Ortho-dihydroxylated flavones showed the highest inhibitory activity on en zymic and non-enzymic microsomal lipid peroxidation as well as on peroxyl radical scavenging. Most flavones were weak scavengers of hydroxyl radical, while ortho-dihydroxylated flavones interacted with superoxide anion generated by an enzymic system or by human neutrophils. This series of compounds did not exert cytotoxic effects on these cells. Scavenging of superoxide and peroxyl radicals may determ ine the anti…