Magnetic Resonance Studies of Hybrid Nanocomposites Containing Nanocrystalline TiO and Graphene-Related Materials.

Nanocomposites based on nanocrystalline titania modified with graphene-related materials (reduced and oxidized form of graphene) showed the existence of magnetic agglomerates. All parameters of magnetic resonance spectra strongly depended on the materials' modification processes. The reduction of graphene oxide significantly increased the number of magnetic moments, which caused crucial changes in the reorientation and relaxation processes.

Preparation and in vitro antioxidant activity of some novel flavone analogues bearing piperazine moiety.

Background: A series of eight new flavone derivatives containing a piperazine chain with different substitution were synthesized and their structures were determined.

Methods: Their antiradical and antioxidant activities were evaluated using superoxide anion radical, hydroxyl radical, 2,2-diphenyl-1-picrylhydrazyl radical, 2,2'-azino-di(3-ethylbenzthiazoline sulphonate) radical cation (ABTS) scavenging (as measure total antioxidant status TAS), ferric reducing antioxidant power (TAC), and hydrogen peroxide decomposition. The antioxidant activities of the synthesized compounds were compared with standard antioxidants trolox, ascorbic acid, butylated hydroxytoluene (BHT) as positive controls, reference antibiotics (doxycycline, dicloxacillin), and medicinal plants (Menthae piperita, Cistus incanus).

A Study on Synthesis and Antioxidant Activity Comparison of Novel Stilbenebenzamide Compounds.

Background: Stilbene phytalexis (1,2-diphenyloethylen) and benzamide are beneficial for human health. To increase the stilbene ring activity, a new series of its derivatives containing benzamide structure was synthesized and evaluated for their in vitro antioxidant power.

Methods: 1H nuclear magnetic resonance, mass spectroscopy, and chromatographic analyses were used to confirm the successful synthesis.

Synthesis and in vitro antioxidant activity of new pyrimidin/benzothiazol-substituted piperazinyl flavones.

Aim: Synthesis of novel 2(2-hydroxyphenyl) pyrimidine/benzothiazole piperazinyl-substituted flavones end evaluate their antioxidant activity.

Results: Six novel 2-(2-hydroxyphenyl) pyrimidine/benzothiazole-substituted flavones were synthesized, their structures were confirmed by elementary and spectral analyses. The compounds were evaluated for their in vitro antioxidant potency by employing various antioxidant assays.

Synthesis and in vitro Antioxidant Activity Study of Some Novel Substituted Piperazinyl Flavone Compounds.

Background: A new series of 13 piperazinyl flavone derivatives has been synthesized and examined for their in vitro antiradical and antioxidant activities in response to the pharmacy industry's increasing demand for new non-toxic anti-inflammatory and anticancer drugs.

Method: Their antioxidant activity was evaluated by the reactive oxygen species (ROS) scavenging assays, 2,2-diphenyl-1-picrylhydrazyl free radical (DPPH•) and 2,2'-azino-bis(3- ethylbenzothiazoline-6-sulphonic acid) radical cation (ABTS+•) scavenging assays, and the ferric reducing antioxidant potency (TAC) method, and was compared to known positive controls, herbal infusions, and penicillins. Chemiluminescence, spectrophotometry, electron spin resonance (ESR) and 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) as the spin trap were the measurement techniques.

Synthesis and in vitro antioxidant activity study of some new piperazinyl flavone compounds.

Flavones exhibit a variety of beneficial effects and are well known for their medicinal importance in several diseases, including cardiovascular, neurodegenerative and cancer. The inclusion of the piperazine ring to the flavone backbone is an important strategy in drug discovery but only a few studies have synthesized piperazinyl flavone compounds to test their biological activity. While there is a major focus on the antioxidant properties of drugs in therapy of several diseases of inflammatory origin, we synthesized a series of the novel piperazinyl flavone analogues bearing the phenyl ring with different substituents.

Radical-scavenging activity of penicillin G, ampicillin, oxacillin, and dicloxacillin.

The aim of this study was to characterize the antioxidant activity of penicillin G (PG), ampicillin (AMP), oxacillin (OX) and dicloxacillin (DOX) through their reactivity towards reactive oxygen species (superoxide anion radical, O2•̅; hydroxyl radical, HO ; peroxyl radical, ROO ; hydrogen peroxide, H O ; DPPH ) using various in vitro antioxidant assays with chemiluminescence (CL) and spectrophotometry as measurement techniques. In hydroxyl radical assays , PG, OX and AMP were found to inhibit the CL signal arising from the Fenton-like reaction in a dose-dependent manner with IC  = 0.480 ± 0.

Studies on the antioxidant properties of some phytoestrogens.

Isoflavones genistein and daidzein are nonsteroidal phytoestrogens occurring mainly in soybean foods. These phytoestrogens possess estrogenic properties and show a variety of health benefits as anti-inflammatory agents. However, the mechanism of their action has not been identified in detail.

[Diagnostics of approximal caries - literature review].

The most important issue in modern cariology is the early diagnostics of carious lesions, because only early detected lesions can be treated with as little intervention as possible. This is extremely difficult on approximal surfaces because of their anatomy, late onset of pain, and very few clinical symptoms. Modern diagnostic methods make dentists' everyday work easier, often detecting lesions unseen during visual examination.

[Remineralizing methods in early caries lesions - review of the literature].

Early diagnosis and treatment of early caries lesions are the basic tenets of minimally invasive dentistry. One of the key elements of a biological approach is the usage of remineralizing agents, which are great alternative to surgical intervention. This article shows a review of the literature concering materials used for the treatment of early caries lesions.

Studies on the antioxidant activity of some chromonylrhodanine derivatives.

Fifteen chromonylrhodamine derivatives (CRs) were synthesized and the antioxidant activity levels were evaluated for the first time. The antioxidant activity potencies of these chromone derivatives were evaluated towards superoxide anion radicals, hydroxyl radicals and 2,2-diphenyl-1-picrylhydrazyl radicals. Also, the total antioxidant capacity of the tested compounds was measured using the ferric-ferrozine assay.

Studies on the antioxidant activity of some thiazolidinedione, imidazolidinedione and rhodanine derivatives having a flavone core.

A series of flavonyl-2,4-thiazolidinedione, imidazolidinedione and rhodanine derivatives were tested for their antioxidant activity as scavengers of oxygen free radicals. Free radical scavenging activities, including superoxide anion radical O2•, hydroxyl radical (HO(•)) and 2,2'-diphenyl-1-picrylhydrazyl free radical have been evaluated using chemiluminescence, electron paramagnetic resonance and spin trapping with 5,5-dimethyl-1-pyrroline-1-oxide as a spin trap. Potassium superoxide in dimethylsulfoxide and 18-crown-6 ether were used for the production of O2•.

Studies on the antioxidant activities of some new chromone compounds.

Recent reviews evidence that the naturally occurring compounds containing the chromone skeleton exhibit antiradical activities, providing protection against oxidative stress. The antioxidant activities of 13 new synthesized chromonyl-2,4-thiazolidinediones, chromonyl-2,4-imidazolidinediones and chromonyl-2-thioxoimidzolidine-4-ones were evaluated using in vitro antioxidant assays, including superoxide anion radical (O2(-•)), hydroxyl radical (HO(•)), 2,2-diphenyl-1-picryl-hydrazyl free radical (DPPH(•)) scavenging capacity and total antioxidant capacity ferric ion reducing activity. Superoxide anion radical was produced using potassium superoxide/18-crown-6-ether dissolved in dimethylsulfoxide, and the Fenton-like reaction (Fe(II) + H2O2) was a generator of hydroxyl radicals.

Antioxidant activities of some new chromonyl-2,4-thiazolidinediones and chromonyl-2,4-imidazolidinediones having chromone cores.

The antioxidant properties of 11 new synthesized chromonyl-2,4-thiazolidinediones and chromonyl-2,4-imidazolidinediones (CBs) were investigated. The antioxidant activities and mechanisms of the CBs interaction with reactive oxygen species (ROS) were clarified using various in vitro antioxidant assay methods including superoxide anion radical (O2(•-)), hydroxyl radical (HO(•)), 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH(•)) scavenging activity and the iron (II)-ferrozine complex formation. The potassium superoxide/18-crown-6 ether dissolved in dimethylsulfoxide (DMSO) was applied as a source of superoxide anion radical.

6-Methyl 3-chromonyl 2,4-thiazolidinedione/2,4-imidazolidinedione/2-thioxo-imidazolidine-4-one compounds: novel scavengers of reactive oxygen species.

The benefits of antioxidants on human health are usually ascribed to their potential ability to remove reactive oxygen species providing protection against oxidative stress. In this paper the free radicals scavenging activities of nine 6-methyl 3-chromonyl derivatives (CMs) were evaluated for the first time by the chemiluminescence, electron paramagnetic resonance, spin trapping and 2,2-diphenyl-1-picrylhydrazyl (DPPH(•)) methods. The total antioxidant capacity was also measured using a ferric-ferrozine reagent.

Superoxide anion radical scavenging property of catecholamines.

The direct effect of the four catecholamines (adrenaline, noradrenaline, dopamine and isoproterenol) on superoxide anion radicals (O2•) was investigated. The reaction between 18-crown-6-ether and potassium superoxide in dimethylsulfoxide was used as a source of O2•. The reactivity of catecholamines with O2• was examined using chemiluminescence, reduction of nitroblue tetrazolium and electron paramagnetic resonance spin-trapping techniques.

Free radical scavenging activity of novel thiazolidine-2,4-dione derivatives.

Free radical activity towards superoxide anion radical (O2•¯), hydroxyl radical (HO(•)) and 2,2-diphenyl-1-picrylhydrazyl (DPPH(•)) of a series of novel thiazolidine-2,4-dione derivatives (TSs) was examined using chemiluminescence, electron paramagnetic resonance (EPR) and EPR spin trapping techniques. 5,5-Dimethyl-1-pyrroline-N-oxide (DMPO) was applied as the spin trap. Superoxide radical was produced in the potassium superoxide/18-crown-6 ether dissolved in dimethyl sulfoxide.

Evaluation of the antioxidant activity of tetracycline antibiotics in vitro.

Tetracyclines are the second most common antibiotic family in medicine usage. These antibiotics exhibit antioxidant potential; however, the exact mechanism remains unclear. The antiradical activity of the seven tetracyclines (TCs; tetracycline, chlortetracycline, oxytetracycline, doxocycline, methacycline, demeclocycline, minocycline) was determined using the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH(•)) and hydroxyl radicals (HO(•)) generated in a Fenton reaction.

Scavenging of hydroxyl radical by catecholamines.

The direct effects of the four catecholamines (CATs), adrenaline (A), noradrenaline (NA), dopamine (D) and isoproterenol (I), on free radicals were investigated using the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH(•)) and hydroxyl radial (HO(•)). The CATs examined were found to inhibit the ESR signal intensity of DPPH(•) in a dose-dependent manner over the range 0.1-2.

Characterization of the superoxide anion radical scavenging activity by tetracycline antibiotics in aprotic media.

The tetracycline family antibiotics are widely used as human and veterinary treatments. The drugs are effective as antibiotics and also show antimicrobial and non-microbial action. However, the antioxidant properties of tetracyclines have not been characterized in aprotic media.

Chemiluminescence investigations of antioxidative activities of some antibiotics against superoxide anion radical.

A chemiluminescent technique was applied to determine antioxidative activities of adriamycin, farmorubicin, mitomycin C and bleomycin against superoxide anion radical (O(2)(•)) in aprotic medium. The antioxidant capacity was expressed as the decrease in light emission from the O(2)(•) solution by and antibiotic. A KO(2) solution in dimethyl sulphoxide (DMSO) and 18-crown-6 ether were used for the generation of O(2)(•).

Diffraction of a Gaussian beam in a three-dimensional smoothly inhomogeneous medium: an eikonal-based complex geometrical-optics approach.

We present an ab initio account of the paraxial complex geometrical optics (CGO) in application to scalar Gaussian beam propagation and diffraction in a 3D smoothly inhomogeneous medium. The paraxial CGO deals with quadratic expansion of the complex eikonal and reduces the wave problem to the solution of ordinary differential equations of the Riccati type. This substantially simplifies the description of Gaussian beam diffraction as compared with full-wave or parabolic (quasi-optics) equations.