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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. 5,5-Dimethyl-1-pyrroline-N-oxide was included as the spin trap. The results showed that the four catecholamines were effective and efficient in inhibiting chemiluminescence accompanying the potassium superoxide/18-crown-6-ether system in a dose-dependent manner over the range 0.05-2 mM in the following order: adrenaline > noradrenaline > dopamine > isoproterenol, with, IC50 = 0.15 ± 0.02 mM 0.21 ± 0.03 mM, 0.27 ± 0.03 mM and 0.50 ± 0.04 mM, respectively. The catecholamines examined also exhibited a strong scavenging effect towards O2• when evaluated this property by the inhibition of nitroblue tetrazolium reduction (56-73% at 1 M concentration). A very similar capacity of O2• scavenging was monitored in the 5,5-dimethyl-1-pyrroline-N-oxide spin-trapping assay. The results suggest that catecholamines tested may involve a direct effect on scavenging O2- radicals., (Copyright © 2013 John Wiley & Sons, Ltd.)

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 0.1-2.5 mmol/L in the following order: NA > A > I > D, with IC50= 0.30 ± 0.03 for noradrenaline and IC50= 0.86 ± 0.02 for dopamine. Hydroxyl radicals were produced using a Fenton reaction in the presence of the spin trap 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and ESR technique was applied to detect the CATs reactivity toward the radicals. The reaction rates constant (k(r)) of CATs with HO(•) were found to be in the order of 10(9)  L/mol/s, and the k(r) value for noradrenaline was the highest (k(r)= 8.4 × 10(9)  L/mol/s). The CATs examined exhibited also a strong decrease in the light emission (62-73% at 1 mmol/L concentration and 79-89% at 2 mmol/L concentration) from a Fenton-like reaction. These reactions may be relevant to the biological action of these important polyphenolic compounds., (Copyright © 2012 John Wiley & Sons, Ltd.)

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. Electron spin resonance (ESR), ESR spin-trapping, chemiluminescence and spectrophotometry techniques were applied. It was found that the TCs showed high DPPH antiradical activity in the range 26-96% at 2.5 mmol/L concentration. The second-order rate constants for the reaction between HO(•) and TCs were calculated, in the range (3.6-9.6) × 10(9)  L/mol/s. The tetracycline compounds also exhibited a strong decrease in light emission (range 61-85% at concentration of 1 mmol/L). This study also showed that TCs promote the generation of singlet oxygen in the presence of H(2)O(2) and Fe(II)/Fe(III) ions. Our findings suggest direct scavenging activity of the examined tetracyclines towards free radicals, and may be relevant to therapeutic strategy., (Copyright © 2011 John Wiley & Sons, Ltd.)

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)(•). The results showed that the examined compounds decreased the chemiluminescence (CL) sum from the O(2)(•)-generating system in a dose-dependent manner. Among the antibiotics examined, adriamycin, farmorubicin and bleomycin exhibited antioxidant activity almost comparable to that of 1,2-dihydroxy benzene-3,5-disulphonic acid (tiron), an efficient of the O(2)(•) inhibitor. Mitomycin C was two-times less effective as tiron in decreasing the initial CL intensity. The proposed assay with usage of ultraweak CL technique and the KO(2)-DMSO-crown ether system was useful for the evaluation of antioxidant activity in aprotic solvents., (Copyright © 2011 John Wiley & Sons, Ltd.)

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. To better understand their biological functions, the in vitro superoxide anion radical (O2•¯) scavenging activities of tetracycline, chlortetracycline, oxytetracycline, doxycycline and methacycline were characterized, along with a very efficient O2•¯ scavenger, tiron, in dimethyl sulphoxide (DMSO), using ultra-weak chemiluminescence (CL). We found that tetracycline, chlortetracycline and doxycycline efficiently inhibited CL from the O2•¯-generating system at concentration levels of 0.02-1.0 mmol/L. Methacycline and oxytetracycline were the O2•¯ scavengers at concentration levels of 0.01-0.1 mmol/L, whereas when their concentration was lowered the drugs were capable of generating O2•¯, leading to CL enhancement. For all the data obtained in this study, the scavenging activity for the compounds tested decreased in the following order: tetracycline > doxycycline > chlortetracycline > tiron methacycline > oxytetracycline. These results indicate that the tetracycline drugs directly alter O2•¯ redox chemistry in aprotic media., (Copyright © 2011 John Wiley & Sons, Ltd.)

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. The oxygen free radicals and singlet oxygen ((1)O(2)) formation was traced by three different assay methods: chemiluminescence (CL), an electron spin resonance (ESR) spin trapping with 2,2,6,6-tetramethyl-4-piperidine and 5,5-dimethyl-1-pyrroline-1-oxide, and spectrophotometric determination of (1)O(2) based on bleaching of p-nitrosodimethylaniline. The effect of hydroxyl radical inhibitors and (1)O(2) quenchers on peroxidation of carazolol was also examined. The results indicated that carazolol enhanced the HO radical and (1)O(2) formation in a Fenton-like reaction., (Copyright © 2010 John Wiley & Sons, Ltd.)

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., (Copyright 2008 John Wiley & Sons, Ltd.)

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. The results indicated that 11 of the 15 tested compounds showed a significant inhibitory effect on the chemiluminescence generated from the O2(-*)-generating system, ranging from 41 to 86%, and 13 CTDs quenched the ESR signal of the DMPO-OH spin adduct by 33-86%, at a concentration of 1 mmol L(-1). Our findings demonstrate that CTDs could be good free radical scavengers.

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%). These results indicate that majority of the indole esters tested possess the ability to scavenge O(-) (2) and HO radicals and to quench (1)O(2) directly, and consequently may be considered effective antioxidative agents., ((c) 2007 John Wiley & Sons, Ltd.)

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 6.15) for HO(*), and a mixture of alkaline aqueous H(2)O(2) and cobalt ions for (1)O(2). We have employed chemiluminescence, electron spin resonance spin trapping, and spectrophotometry techniques to examine an antioxidative property. All tested compounds acted as scavengers of various reactive oxygen species. The reactivity indexes (beta) for the reaction of the phenolic compounds with HO(*) were calculated., (Copyright 2007 Wiley Periodicals, Inc.)

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(.-)(2), the Fenton-like reaction (Cu/H(2)O(2)) for hydroxyl radical (HO(.)), 2,2'-azobis (2-amidino-propane) dichloride (AAPH) as peroxyl radical (ROO(.)) generator, and a mixture of alkaline aqueous H(2)O(2) and acetonitrile for singlet oxygen ((1)O(2)). Measurements were done using chemiluminescence, fluorescence, and spin-trapping with 2,2,6,6-tetramethylpiperidine combined with electron spin resonance spectroscopy (ESR), and a deoxyribose assay based on the spectrophotometry. The results obtained demonstrated that all tested drugs were active against O(.-)(2). There was a clear ranking of drug inhibition effects on chemiluminescence from the O(.-)(2) system: ketoprofen > tolmetin > fenofibrate. The examined compounds inhibited the HO(.)-dependent deoxyribose degradation and scavenged the ROO(.) concentration dependently with an order of potencies similar to that of the superoxide radical system. Hence, these results indicate that the studied drugs show broad ROS scavenging property and, as a consequence, might decrease tissue damage due to the ROS and thus to contribute to anti-inflammatory therapy.

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. Chemiluminescence, fluorescence, electron paramagnetic resonance (EPR) spin-trapping techniques and the deoxyribose and oxygen radical absorbance capacity towards ROO(*) (ORAC(ROO)) assays were used to elucidate the anti- and pro-oxidative behaviours of BUC towards ROS. The results indicated that BUC efficiently inhibited chemiluminescence from the O(2) (*-)-generating system at relatively high concentrations (0.5-2 mmol/L); however, at lower concentrations (<0.5 mmol/L) the drug enhanced light emission. The behaviour of BUC was correlated with a capacity to decrease the chemiluminescence signal from the Cu(2+)-H(2)O(2) system; scavenging HO(*) was effective only at high concentrations (1-2 mmol/L) of the drug. Bucillamine also prevented deoxyribose degradation induced by HO(*) in a dose-dependent manner, reaching maximal inhibition (24.5%) at a relative high concentration (1.54 mmol/L). Moreover, BUC reacts with ROO(*); the relative ORAC(ROO) was found to be 0.34 micromol/L Trolox equivalents/micromol sample. The drug showed quenching of (1)O(2)-dependent 2,2,6,6-tetramethylpiperidine-N-oxide radical formation from 2,2,6,6-tetramethyl-piperidine (e.g. 90% inhibition was found at 1 mmol/L concentration). The results showed that BUC may directly scavenge ROS or inhibit reactions generating them. However, the drug may have pro-oxidant activity under some reaction conditions.

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. The risk of developing any late complications after conventionally fractionated megavoltage radiotherapy is estimated to be below 1%. The aim of this review is to determine whether hypofractionated regimens increase the risk of damage to the brachial plexus. A review of the published literature shows that the use of doses per fraction in the range from 2.2 Gy to 4.58 Gy with the total doses between 43.5 Gy and 60 Gy causes a significant risk of brachial plexus injury which ranged from 1.7% up to 73%. The risk of radiation induced brachial plexopathy was smaller than 1% using regimens with doses per fraction between 2.2 and 2.5 Gy with the total doses between 34 and 40 Gy. Surgical manipulations in the axilla and chemotherapy have to be taken into account as additional factors which may increase the risk of brachial plexopathy.

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., ((c) 2005 Wiley Periodicals, Inc.)

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).(-)) and hydrogen peroxide (H(2)O(2)); (b) the Co(II)-EDTA-H(2)O(2) system (the Fenton-like reaction), which generates hydroxyl radical (HO.); (c) 2,2'-azobis(2-amidino-propane)dichloride (AAPH) as the peroxyl radical (ROO.) generator, and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical test. Results showed that genistein and oleuropein decreased the chemiluminescence sum from the O(2).(-) generating system, an inhibitory effect that was dependent on their concentration. These compounds also reacted with ROO radicals and they showed activity about two-fold greater than the standard Trolox. The antioxidant effects were studied at different concentrations and reflected in protection against the fluorescence decay of beta-phycoerythrin (beta-PE), due to ROO. attack on this protein. Using the Fenton-like reaction and the spin trap agent 5,5-dimethyl-1-pyrroline-N-oxide (DMPO), the phenolic compounds examined were found to inhibit DMPO-.OH radical formation in the range 10-90% at concentrations of 0.1 mmol/L to 2 mmol/L. Furthermore, these compounds also inhibited HO.-dependent deoxyribose degradation; about 20% and 60% inhibitions were observed in the presence of 0.5 mmol/L genistein and oleuropein, respectively. It was also demonstrated that genistein had a weaker DPPH radical scavenging activity than oleuropein. Our results confirm good scavenging activity towards O(2).(-), HO. and ROO. and the antioxidant effect of genistein and oleuropein., (Copyright (c) 2005 John Wiley & Sons, Ltd.)

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. Another groups had a following supplements: rats were allowed to drink distilled water containing vitamin C (vit C) at concentration of 500 mg/l or Trolox (a vitamin E analog) at concentration of 48 mg/l or vit C (500 mg/l) + Trolox (48 mg/l). The similar groups among Pb-treated animals were examined after treatment with the same vitamins and using the same vitamin doses, dissolved in 1% aqueous solution of lead acetate. In all cases the time of drinking was 6 months. It was found that lead content in samples of tissues from testis, epididymis and in a whole blood in Pb- and Pb with antioxidants treated rats was significantly elevated. Chemiluminescence (CL) emitted by the Pb-treated tissues was significantly higher when compared to the light emission by tissues isolated from the animals of control group. The increase in the CL caused by lead occurs in the following increasing order within the studied tissues: cauda of epididymis < testis < caput of epididymis (19%, 39% and 51%, respectively). Dietary vit C supplementation to the Pb-treated rats for 6 months period decreased the CL from caput of epididymis, cauda of epididymis and testis (by 43%, 24%, 39%, respectively) more effectively in comparison to the control group (35%, 17%, 33%, respectively). Also stronger quenching effect on the light emission from the above mentioned tissues after Trolox supplementation was observed in the Pb-treated group (42%, 21%, 35%, respectively) than in the control group (23%, 13%, 13% respectively). The combination of both antioxidants treatments (vit C and Trolox) did not give a higher significant quenching effect compared to the treatment with the vitamins separately. No ultrastructural changes were found in the seminiferous epithelium of Pb-treated animals. However, we found abnormalities in ultrastructure of epididymal epithelial cells and epididymal spermatozoa in rats of Pb-treated groups. These findings provide ex vivo evidence that Pb causes oxidative cellular damage in reproductive system tissues of adult male rats, which may be closely associated with the ROS production.

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. All test compounds at a concentration of 0.5 mM enhanced the CL from O(2)(.-) up to fivefold, which was recorded as the light sums during 1 min. At 0.38 mM PBAD enhanced production of HO(*) from H(2)O(2) in the presence of Co(II) up to 90%, as measured by a deoxyribose assay. Using the spin trap agent 5,5-dimethyl-1-pyrroline-N-oxide, it was found that the amplitude of the signal arising from the Fenton-like reaction [Co(II)/H(2)O(2)] was significantly diminished by the test compounds. The compounds also inhibited the (1)O(2) dependent 2,2,6,6-tetramethylpiperidine-N-oxide radical, which is generated in the acetonitrile/H(2)O(2) system. The measured rate constants of (1)O(2)-dimol quenching by PBAD were in the range of (0.8-2.6) x 10(8) M(-1) s(-1). The interaction between PBAD and (1)O(2) was also checked using a spectrophotometry method based on bleaching of p-nitrosodimethylaniline. These results indicate that PBAD may directly scavenge HO(*) and (1)O(2), but not O(2)(.-). However, the compounds that were examined had prooxidant ability under some reaction conditions., (2004 Wiley Periodicals, Inc.)