PURPOSE: The purpose of the paper was to investigate the protective effect of some scavengers of OH radicals (hydroxyl radicals) on the radiation sensitivity of bacteria (in some cases also yeast) under normoxic (in air) or hypoxic (suboxic) conditions and to compare the obtained results with those published earlier for the yeast, all in a wide interval of irradiation conditions. Another aim was to investigate a possible impact of the reaction order of the reaction between the scavengers and the OH radicals on the protection of the cells. MATERIALS AND METHODS: In order to study the protective effect of OH scavengers we used various concentrations of methanol and potassium formate (in some cases also ethanol) in isotonic salt solutions. These solutions containing living bacteria (Escherichia coli) or yeast (Saccharomyces cerevisiae) were irradiated with 60Co radiation using various doses and dose rates. Irradiation was performed in air, in some cases under the hypoxic conditions. The number of surviving cells was determined prior to and after irradiation in suspension with and without scavengers. The surviving fractions after irradiation with and without scavenger were evaluated. RESULTS: The surviving fraction of bacterial cells increases linearly with increasing concentration of both scavengers. The fraction of surviving cells does not increase with increasing concentration of the scavengers under suboxic conditions. The protective effect Ϭ increases linearly with increasing scavenging efficiency and this dependence is much sharper under normoxic conditions than under suboxic ones. The specific protection k is much higher for the methanol than for the potassium formate. CONCLUSIONS: The basic characteristics of the impact of scavengers of OH radicals on radiation sensitivity of both bacteria and yeast are the same in a wide interval of doses and dose rates. The specific protection effect is much higher under the normoxic conditions. This protective effect is inversely proportional to the rate constant of the reaction between the scavenger and the OH radicals. It seems to be obvious that the presence of oxygen during irradiation is a necessary condition for the protective action of the scavengers which may be partially controlled by some transport processes and may be connected with the radiation sensitivity of the cells. On the other hand, the change of the reaction order of the reaction of the scavenger with the OH radicals has turned out to be unimportant.

• Klíčová slova
• Dose-response curve, hydroxyl radicals, radiation chemistry, radiation protection, radioprotectors,
• MeSH
• Escherichia coli cytologie   účinky léků   metabolismus   účinky záření   MeSH
• hydroxylový radikál metabolismus   MeSH
• scavengery volných radikálů metabolismus   farmakologie   MeSH
• tolerance záření účinky léků   MeSH
• viabilita buněk účinky léků   účinky záření   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• hydroxylový radikál MeSH
• scavengery volných radikálů MeSH

The ethanol extracts of 47 mushroom species from the order Boletales were tested for their free radical scavenging activities by means of the DPPH free-radical scavenging and hydrogen peroxide-induced luminol chemiluminescence assays. In the DPPH radical scavenging test, 26 species gave EC50 values of less than 1 mg/mL. The highest activity was exhibited by Gyrodon lividus (0.05 mg/mL). However, in the hydrogen peroxide-induced luminol chemiluminescence assay, only 4 species had EC50 values of less than 1 mg/mL, with the highest activity being exhibited by Strobilomyces floccopus (0.26 mg/mL). When compared with known antioxidants, all the mushroom extracts exhibited relatively low activity in both assays. The free radical scavenging results appeared to be correlated with the total phenol contents of the extracts.

• MeSH
• Agaricales chemie   MeSH
• bifenylové sloučeniny chemie   MeSH
• pikráty chemie   MeSH
• scavengery volných radikálů chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1,1-diphenyl-2-picrylhydrazyl MeSH Prohlížeč
• bifenylové sloučeniny MeSH
• pikráty MeSH
• scavengery volných radikálů MeSH

PURPOSE: To quantitatively investigate the influence of various •OH (hydroxyl radical) scavengers on the radiation sensitivity of yeast and bacteria, particularly to define the relationship between the protective effect of a scavenger and its •OH scavenging efficiency. MATERIALS AND METHODS: In order to study the protective effect of •OH scavengers we used various concentrations of four scavengers (methanol, potassium formate, ethanol and ascorbic acid) in isotonic salt solutions. These solutions containing live yeast (Saccharomyces cerevisiae) or bacteria (Escherichia coli) were irradiated with (60)Co isotope γ -radiation using two different doses and dose rates. The number of surviving cells was determined prior to and after irradiation both in suspension with and without scavengers. The surviving fractions after irradiation with and without the scavenger were evaluated. RESULTS AND CONCLUSIONS: The main results of the paper were: The surviving fraction increased approximately linearly within the measured interval with increasing concentration of the scavenger. The same dependences were found for the protecting effect depending on the scavenging efficiency. The slopes of these dependences (k) were found to be characteristic for each scavenger. The k value determined the degree in which the scavenging of •OH radicals participated in the protection of living cells. The protective effects of scavengers at the same scavenging efficiency were different and unique for each scavenger. No simple relation was found between the efficiency of scavenger k and the rate constant kOH of the reactions between scavengers and •OH radicals. Our results suggest that the studied scavengers effectively protected yeast and bacteria against ionizing radiation. Although the scavenging of •OH radicals seems to be important for protection of living cells, it is clearly not the only process on which the protection is based.

• MeSH
• Escherichia coli účinky léků   účinky záření   MeSH
• hydroxylový radikál * MeSH
• ionizující záření MeSH
• radioizotopy kobaltu chemie   MeSH
• Saccharomyces cerevisiae účinky léků   účinky záření   MeSH
• scavengery volných radikálů * MeSH
• tolerance záření účinky léků   MeSH
• záření gama MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• hydroxylový radikál * MeSH
• radioizotopy kobaltu MeSH
• scavengery volných radikálů * MeSH

The influence of various hydroxyl radical scavengers such as methanol, ethanol and dimethyl sulfoxide on radiation sensitivity of prokaryotic cells (bacteria Escherichia coli) and eukaryotic cells (yeast Saccharomyces cerevisiae and V79 cells-Chinese hamster pulmonary fibroblasts) irradiated by 60Co gamma radiation was investigated. The dependence of radiation sensitivity on dose rate in range from 1.8 to 100 Gy h-1 was evaluated. Survival of cells irradiated by increasing dose rates was followed using clonogenic assay. Specific protective effect was found to be a nonmonotonous function of dose rate with typical maximum at the dose rate range from 50 to 55 Gy h-1 in all studied cell types.

• MeSH
• CHO buňky MeSH
• Cricetulus MeSH
• dimethylsulfoxid farmakologie   MeSH
• Escherichia coli účinky léků   účinky záření   MeSH
• ethanol farmakologie   MeSH
• fibroblasty účinky léků   účinky záření   MeSH
• hydroxylový radikál * MeSH
• methanol farmakologie   MeSH
• poškození DNA MeSH
• radiační ochrana MeSH
• radioizotopy kobaltu farmakologie   MeSH
• radioprotektivní látky farmakologie   MeSH
• Saccharomyces cerevisiae účinky léků   účinky záření   MeSH
• scavengery volných radikálů farmakologie   MeSH
• tolerance záření MeSH
• viabilita buněk účinky záření   MeSH
• vztah dávky záření a odpovědi MeSH
• záření gama MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• Cobalt-60 MeSH Prohlížeč
• dimethylsulfoxid MeSH
• ethanol MeSH
• hydroxylový radikál * MeSH
• methanol MeSH
• radioizotopy kobaltu MeSH
• radioprotektivní látky MeSH
• scavengery volných radikálů MeSH

The ethanol extracts of 30 mushroom species from the order Polyporales were tested for their free radical scavenging activities by means of the DPPH free-radical scavenging and hydrogen peroxide-induced luminol chemiluminescence assays. In the DPPH radical scavenging test, 7 species gave EC50 values of less than 1 mg/mL. The highest activity was exhibited by Fomitopsis pinicola (0.09 mg/mL). However, in the hydrogen peroxide-induced luminol chemiluminescence assay, only 4 species had EC50 values of less than 1 mg/mL, with the highest activity being exhibited also by F. pinicola (0.26 mg/mL). When compared with known antioxidants, all the mushroom extracts exhibited relatively low activity in both assays. The free radical scavenging results appeared not to be correlated with the total phenol contents of the extracts.

• MeSH
• Agaricales chemie   MeSH
• bifenylové sloučeniny MeSH
• luminiscenční měření MeSH
• luminol MeSH
• peroxid vodíku MeSH
• pikráty MeSH
• scavengery volných radikálů chemie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH
• Názvy látek
• 1,1-diphenyl-2-picrylhydrazyl MeSH Prohlížeč
• bifenylové sloučeniny MeSH
• luminol MeSH
• peroxid vodíku MeSH
• pikráty MeSH
• scavengery volných radikálů MeSH

Total phenolic content, reducing power, antioxidant and free radical scavenging activities of ethanol extracts of five mosses were determined in vitro. No correlation between the total phenolic content and antioxidant or scavenging activities was found.

• MeSH
• antioxidancia aplikace a dávkování   farmakologie   terapeutické užití   MeSH
• bifenylové sloučeniny MeSH
• Bryophyta klasifikace   MeSH
• fytoterapie * MeSH
• inhibiční koncentrace 50 MeSH
• lidé MeSH
• oxid dusnatý chemie   MeSH
• pikráty chemie   MeSH
• rostlinné extrakty aplikace a dávkování   farmakologie   terapeutické užití   MeSH
• scavengery volných radikálů aplikace a dávkování   farmakologie   terapeutické užití   MeSH
• volné radikály chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1,1-diphenyl-2-picrylhydrazyl MeSH Prohlížeč
• antioxidancia MeSH
• bifenylové sloučeniny MeSH
• oxid dusnatý MeSH
• pikráty MeSH
• rostlinné extrakty MeSH
• scavengery volných radikálů MeSH
• volné radikály MeSH

Puerarin-7-O-fructoside was transformed by Trichoderma harzianum CGMCC 1523 into 3'-hydroxypuerarin-7-O-fructoside; this was identified by MS and NMR. However, puerarin-7-O-glucoside was not directly hydroxylated but hydrolyzed back into puerarin, which was transformed into 3'-hydroxypuerarin by the same fungi. Comparative analysis of free radical scavenging activity of DPPH showed that the free radical scavenging activity of puerarin-7-O-glucoside was reduced to approximately 1/2 of that of puerarin, while the free radical scavenging activity of puerarin-7-O-fructoside was increased to approximately 1.5 times of that of puerarin. The free radical scavenging activity of 3'-hydroxypuerarin-7-O-fructoside was further increased by 2.2 times of that of puerarin-7-O-fructoside, which was close to that of 3'-hydroxypuerarin.

• MeSH
• biotransformace MeSH
• fruktosa analogy a deriváty   chemie   metabolismus   MeSH
• glykosylace MeSH
• hydroxylace MeSH
• isoflavony chemie   metabolismus   MeSH
• scavengery volných radikálů chemie   metabolismus   MeSH
• Trichoderma metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fruktosa MeSH
• isoflavony MeSH
• puerarin-7-O-fructoside MeSH Prohlížeč
• scavengery volných radikálů MeSH

Functional and morphological consequences of ischemic lesions are partially related to the production of reactive oxygen species (ROS). The aim of the study was to create a unilateral photothrombic lesion with minimal morphological changes and minor sensorimotor and cognitive deficits and also to test whether the application of ROS scavengers after the end of induction of ischemia had improved the functional outcome. Adult Wistar male rats were randomly divided into five groups: naive control, sham operated animals, animals with induced ischemia, and two groups of animals with induced ischemia and subsequent ROS scavenger application -melatonin or tempol. The group subjected to ischemia showed a significant decline in performance in sensorimotor tests and the Morris water maze (MWM) test, compared to control animals. Tempol (50 mg/kg, i.p.) did not improve sensorimotor function and did not change spatial learning. Melatonin (100 mg/kg, i.p.), on the contrary, resulted in a significant improvement in animals' performances. All the ischemia subjected animals had increased speed of swimming in the MWM test, compared to the control group. Our findings showed that subsequent application of ROS scavengers improve ischemia outcomes, with melatonin being more potent. Conversely, neither melatonin, nor tempol decreased swimming speed cased by ischemia.

• MeSH
• bludiště - učení MeSH
• časové faktory MeSH
• chování zvířat MeSH
• cyklické N-oxidy farmakologie   MeSH
• ischemie mozku patologie   MeSH
• ischemie patologie   MeSH
• kognice MeSH
• krysa rodu Rattus MeSH
• melatonin farmakologie   MeSH
• neuroprotektivní látky farmakologie   MeSH
• potkani Wistar MeSH
• reaktivní formy kyslíku MeSH
• scavengery volných radikálů * MeSH
• senzorická zpětná vazba MeSH
• spinové značení MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• cyklické N-oxidy MeSH
• melatonin MeSH
• neuroprotektivní látky MeSH
• reaktivní formy kyslíku MeSH
• scavengery volných radikálů * MeSH
• spinové značení MeSH
• tempol MeSH Prohlížeč

Radical scavenging and anti-lipoperoxidative effects of two organic fractions and two aqueous extracts from the leaves of a neglected Andean crop-yacon (Smallanthus sonchifolius Poepp. & Endl., Asteraceae) were determined using various in vitro models. The extracts' total phenolic content was 10.7-24.6%. They exhibited DPPH (IC50 16.14-33.39 microg/mL) and HO* scavenging activities (4.49-6.51 mg/mL). The extracts did not scavenge phenylglyoxylic ketyl radicals, but they retarded their formation. In the xanthine/xanthine oxidase superoxide radical generating system, the extracts' activities were 26.10-37.67 superoxide dismutase equivalents/mg. As one of the extracts displayed xanthine oxidase inhibitory activity, the effect of the extracts on a nonenzymatically generated superoxide was determined (IC50 7.36-21.01 microg/mL). The extracts inhibited t-butyl hydroperoxide-induced lipoperoxidation of microsomal and mitochondrial membranes (IC50 22.15-465.3 microg/mL). These results make yacon leaves a good candidate for use as a food supplement in the prevention of chronic diseases involving oxidative stress.

• MeSH
• Asteraceae chemie   MeSH
• bifenylové sloučeniny MeSH
• fenoly analýza   MeSH
• hydroxylový radikál chemie   MeSH
• krysa rodu Rattus MeSH
• listy rostlin chemie   MeSH
• peroxidace lipidů účinky léků   MeSH
• pikráty chemie   MeSH
• potkani Wistar MeSH
• rostlinné extrakty chemie   farmakologie   MeSH
• scavengery volných radikálů chemie   MeSH
• superoxidy chemie   MeSH
• terc-butylhydroperoxid farmakologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1,1-diphenyl-2-picrylhydrazyl MeSH Prohlížeč
• bifenylové sloučeniny MeSH
• fenoly MeSH
• hydroxylový radikál MeSH
• pikráty MeSH
• rostlinné extrakty MeSH
• scavengery volných radikálů MeSH
• superoxidy MeSH
• terc-butylhydroperoxid MeSH

Maghemite (gamma-Fe2O3) nanoparticles, 12 nm in size, were prepared by co-precipitation of Fe(II) and Fe(III) chlorides with ammonium hydroxide and oxidation with hydrogen peroxide. To achieve stability and biocompatibility, obtained particles were coated with silica, to which glucose and ascorbic acid were bound by different mechanisms. The composite particles were thoroughly characterized by transmission electron microscopy, dynamic light scattering, elemental analysis, and FT-Raman and fluorescence spectroscopy to determine composition, morphology, size and its distribution, zeta-potential, and scavenging of peroxyl and hydroxyl radicals. As the particles showed promising antioxidative properties, they may have a possible application as a stable magnetically controlled scavenger of reactive oxygen species.

• MeSH
• dioxolany chemie   MeSH
• furany chemie   MeSH
• glukosa chemie   MeSH
• kyselina askorbová chemie   MeSH
• magnetické nanočástice chemie   ultrastruktura   MeSH
• oxid křemičitý chemie   MeSH
• scavengery volných radikálů chemická syntéza   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 5-(2,2-dimethyl-1,3-dioxolan-4-yl)-2,2-dimethyltetrahydrofuro(2,3-d)(1,3)dioxol-6-yl(3-(tritriethoxysilyl) MeSH Prohlížeč
• dioxolany MeSH
• furany MeSH
• glukosa MeSH
• kyselina askorbová MeSH
• magnetické nanočástice MeSH
• oxid křemičitý MeSH
• scavengery volných radikálů MeSH