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.

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)(•).

Prooxidant action of carazolol in the Fenton-like reaction.

Carazolol [4-(2-hydroxy-3-isopropyl-amino-propoxy)-carbazole], a β(3)-adrenoceptor agonist, is clinically used in the treatment of hypertension, cardiac arrhythmias and angina pectoris. Despite the beneficial effect of the drug, its high dose may contribute to cardiotoxicity. This study was conducted to examine whether carazolol can influence hydroxyl radical formation by a Fenton-like reaction [Co(II) + H(2)O(2) + HO(-)] in the presence of ethylenediaminetetraacetic acid.

Scavenging capacities of some thiazolyl thiazolidine-2,4-dione compounds on superoxide radical, hydroxyl radical, and DPPH radical.

The scavenging effects of eighteen thiazolyl thiazolidine-2,4-dione compounds (TTCs) on superoxide radical ( (-) (*) ) (2), hydroxyl radical HO(*), and 1,1-diphenyl-2-picrylhydrazyl (DPPH(*)) radical were evaluated by the chemiluminescence technique, electron spin resonance spectrometry (ESR) and visible spectrophotometry, respectively. The examined compounds were shown to have 27-59% ( (-) (*) ) (2) scavenging ability, 19-69% HO(*) scavenging activity and 2-32% DPPH(*) scavenging ability. This property of the tested compound seems to be important in the prevention of various diseases of free radicals etiology.

Hydroxyl and superoxide radical scavenging abilities of chromonyl-thiazolidine-2,4-dione compounds.

The oxygen free radical scavenging activities of 15 chromonyl-thiazolidine-2,4-dione compounds (CTDs) were examined in chemical systems producing superoxide anion radicals, O2(-*) (potassium superoxide-18-crown-6 ether-DMSO), and hydroxyl radicals, HO(*) (a Fenton reaction: Fe(II)-H2O2-sodium trifluoroacetate, pH 6.15). Chemiluminescence and electron spin resonance (ESR) spectroscopy using 5,5-dimethyl-1-pyrroline-1-oxide (DMPO) as spin trap were applied to evaluate antioxidant behaviour of CTDs towards the oxygen radicals.

In vitro scavenging activity for reactive oxygen species by N-substituted indole-2-carboxylic acid esters.

The hydroxyl radical (HO*)- and superoxide anion radical (O* (2))-scavenging activity, as well as the singlet oxygen ((1)O(2))-quenching property of N-substituted indole-2-carboxylic acid esters (INDs) were investigated by deoxyribose degradation assay, a chemiluminescence method and the electron spin resonance (ESR) spin-trapping technique. This novel group of compounds was developed as a search for cyclooxygenase-2 (COX-2)-selective enzyme inhibitors. The results obtained demonstrated that of the 16 compounds examined, five inhibited light emission from the superoxide anion radical (O* (2))-DMSO system by at least 60% at a concentration of 1 mmol/L, nine prevented the degradation of deoxyribose induced by the Fenton reaction system (range 3-78%) or scavenged hydroxyl radicals (HO*) directly (range 8-93%) and 14 showed the (1)O(2)-quenching effect (range 10-74%).

Scavenging effects of phenolic compounds on reactive oxygen species.

Phenolic compounds are widely present in plants and they have received considerable attention due to their antioxidant property. In this article we report the results of a study of the reactivity of 10 selected phenolics (sesamol, three phenolic acids, three flavonols, one flavone, and two flavanones) with superoxide anion radical (O(2) (*)), hydroxyl radical (HO(*)) and singlet oxygen ((1)O(2)). The following generators of reactive oxygen species were used: 18-crown-6/KO(2)/dimethylsulfoxide (DMSO) or hypoxanthine/xanthine oxidase as sources of O(2) (*), the Fenton reaction carried out in a sodium trifluoroacetate (pH 6.

Radiation-induced brachial plexopathy and hypofractionated regimens in adjuvant irradiation of patients with breast cancer--a review.

In order to increase the availability of adjuvant radiotherapy of breast cancer patients and make it more convenient and cheaper, in numerous cancer centres, the dose per fraction has been increased from 2 Gy to 2.25-2.75 Gy and the total dose has been decreased from 50 Gy to 40-45 Gy.

Anti-oxidant and pro-oxidant behaviour of bucillamine.

Bucillamine (BUC) is used clinically for the treatment of rheumatoid arthritis. Some of the pharmacological action of BUC has been reported as being dependent on the production of reactive oxygen species (ROS). In this paper the reactivity of BUC with superoxide anion radical (O(2) (*-)) generated from potassium superoxide/18-crown-6 ether dissolved in DMSO, hydroxyl radical (HO(*)) produced in the Cu(2+)-H(2)O(2) reaction, peroxyl radical (ROO(*)) from 2,2'-azobis (2-amidino-propane) dichloride decomposition, and singlet oxygen ((1)O(2)) from a mixture of alkaline aqueous H(2)O(2) and acetonitrile, have been investigated.

Scavenging of reactive oxygen species by some nonsteroidal anti-inflammatory drugs and fenofibrate.

Ketoprofen and tolmetin are widely used nonsteroidal anti-inflammatory drugs, whereas fenofibrate belongs to a family of hypolipidemic drugs used in the prevention of cardiovascular diseases. The aim of this study was to assess effect of these drugs on reactions generating reactive oxygen species (ROS). The following generators of ROS were used: 18-crown-6/KO(2) dissolved in DMSO as a source of superoxide radical (O(.

Scavenging of reactive oxygen species by the plant phenols genistein and oleuropein.

The plant-derived phenolic compounds genistein and oleuropein are known to exhibit several biological properties, many of which may result from their antioxidant and free radical scavenger activity. In this paper we report the results of a complex study of antioxidant activity of genistein and oleuropein, using electron spin resonance (ESR), chemiluminescence, fluorescence and spectrophotometric techniques. Different reaction systems were applied to study the inhibitory effect of the phenolic compounds studied: (a) the potassium superoxide/18-crown-6 dissolved in DMSO system, which generates superoxide radical (O(2).

Scavenging of reactive oxygen species by novel indolin-2-one and indoline-2-thione derivatives.

The antioxidant behavior of a series of new synthesized substituted indoline-2-ones and indolin-2-thiones was investigated in this study using an oxygen radical absorbance capacity assay (ORAC(ROO*-) and 2,2'-azobis(2-amidino-propane) dihydrochloride (AAPH) as the radical generator; system generating superoxide anion radical, O2*- (18-crown-6/KO(2)/DMSO), and the Fenton-like reaction [Co(II) + H(2)O(2) --> Co(III) + HO(*) + HO(-)]. Measurements were done using fluorescence, chemiluminescence methods, and a deoxyribose assay based on the spectrophotometry method, respectively. The results obtained indicated that the examined indoline derivatives had effective activities as radical scavengers and may be considered as an effective source for combating oxidative damage.

Detection of lead-induced oxidative stress in the rat epididymis by chemiluminescence.

It has been shown that lead (Pb) is able to induce lipid peroxidation, one of the main manifestations of oxidative stress. In this study we examined the relationship between chronic Pb exposure and level of reactive oxygen species (ROS) in reproductive system tissues of sexually mature male Wistar rats. One group of animals (control, K) was allowed to drink distilled water, the second group (Pb) was allowed to drink freely 1% aqueous solution of lead acetate.

Prooxidant and antioxidant action of 4-(4-phenoxybenzoyl)benzoic acid derivatives.

4-(4-Phenoxybenzoyl)benzoic acid derivatives (PBADs) were found to inhibit rat and human alpha-reductase isozymes 1 and 2 in vitro. Chemiluminescence (CL), electron spin resonance, spin trapping techniques, and spectrophotometry were used to examine the effect of PBADs on reactive oxygen species (superoxide radical, O(2)(.-); hydroxyl radical, HO(*); singlet oxygen, (1)O(2)) generating systems.

Scavenging of reactive oxygen species by N-substituted indole-2 and 3-carboxamides.

Indole-2 and 3-carboxamides (IDs) are proposed to be selective cyclooxygenase inhibitors. Since cyclooxygenase-1 may be involved in reactive oxygen species (ROS) production, we hypothesize that these indole derivatives have antioxidative properties. We have employed chemiluminescence (CL) and electron spin resonance (ESR) spin trapping to examine this hypothesis.

Effect of psoralens on Fenton-like reaction generating reactive oxygen species.

Psoralens (psoralen, 5-methoxypsoralen, 8-methoxypsoralen, khellin, and visnagin) in 1 mM doses were shown to enhance the generation of reactive oxygen species, such as the hydroxyl radical (HO*), the superoxide anion radical (O2(-)), and singlet oxygen ((1)O(2)), from the system generating chemiluminescence (CL), as well as free radicals in the absence of light. The system that generated CL was made up of CoCl(2) and H(2)O(2). Incubation of psoralens in 0.

Spin trapping study of reactive oxygen species formation during bopindolol peroxidation.

The generation of singlet molecular oxygen ((1)O(2)) and hydroxyl radicals (HO*) during peroxidation of bopindolol in the presence of Co(II) ions was studied using electron spin resonance (ESR) and spectrophotometry methods. 2,2,6,6-Tetramethyl-4-piperidone and 5,5-dimethyl-1-pyrroline-1-oxide were used as traps. The spectrophotometry determination of (1)O(2) was based on bleaching of p-nitrosodimethylaniline (RNO), which was caused by the product of the reaction of (1)O(2) with imidazole and was followed by monitoring the decrease in optical density at 440 nm.

Formation of singlet oxygen during farmorubicin oxidation.

The enhanced generation of singlet oxygen (1O2) during oxidation of farmorubicin in the Co(II) + H2O2 system was studied using chemiluminescent, fluorescent and spectrophotometic techniques. The influence of 1O2-quenchers, catalase, superoxide anion radical (O2*-) and hydroxyl radical (HO*) scavengers on the light emission was studied. The spectrophotometric determination of 1O2 was based on bleaching of p-nitrosodimethylaniline caused by an intermediate product of the reaction of 1O2 with imidazole, and was followed by monitoring the decrease in optical density at 440 nm.

Luminescence investigations of redox cycling of adriamycin.

The light emission from the adriamycin + Co2+ + H2O2 system has been studied. Chemiluminescence, fluorescence and absorption spectra were measured. The fluorescence spectra were time-dependent exhibiting maxima at 555, 590 and 645 nm.

Antioxidant activity of 4-flavonil-1,4-dihydropyridine derivatives.

The effect of 4-flavonil-1,4-dihydropyridine derivatives on a chemical system involving a superoxide radical anion was tested using the chemiluminescence and spectrophotometry methods. All tested compounds enhanced the light emission from the system. The obtained results indicated that the tested derivatives may catalyze the conversion of superoxide radicals, thus showing superoxide dismutase activity.

The effect of thymol and its derivatives on reactions generating reactive oxygen species.

The effects of thymol (TOH), thymoquinone (TQ) and dithymoquinone (TQ2) on the reactions generating reactive oxygen species (ROS) such as superoxide anion radical (O2*-), hydroxyl radical (HO*) and singlet oxygen (1O2) were tested using the chemiluminescence (CL) and spectrophotometry methods. All tested compounds acted as scavengers of various ROS. The rate constant of 1O2-dimols quenching by thymol was calculated.

[Is there true remission in myasthenia gravis? Long-term clinical and electrophysiological studies].

Twenty myasthenic patients were followed up who had in the years 1981-1982 full clinical remission (no drugs, no symptoms), lasting at that time at least several years. However, in 19 of them neuromuscular transmission defects were then found by single fibre electromyography (SFEMG). We then concluded that true remissions did not exist in myasthenia (J.