Abstract：
:Nitroxides stable radicals are unreactive toward most diamagnetic molecules, but readily undergo one-electron redox reactions with paramagnetic species such as free radicals and transition metals, thus serving as cell-permeable antioxidants. The cytotoxicity of juglone (5-hydroxy-1,4-naphthoquinone), like that of other naphthoquinones, requires bioreduction to yield the semiquinone which in turn reduces oxygen to O2.-. Therefore, nitroxides are expected to mitigate cytotoxicity of quinone-based xenobiotics, such as naphthoquinones. In the present study, in vitro scission of isolated DNA was induced upon juglone reduction by glutathione and Fe(II) ions, however, not by xanthine oxidase or cytochrome c reductase. The DNA scission was inhibited by nitroxides, catalase and chelating agents, though not by superoxide dismutase. Juglone was more toxic toward bacterial cells under hypoxia than under air. Nitroxides < or = 2 mM protected bacterial cells from juglone-induced toxicity under both aerobic and hypoxic conditions. The cytoprotective effect of lipophilic nitroxide was greater than that of hydrophilic ones. Catalase and metal chelating agents decreased juglone-induced cell killing, whereas H2O2 increased it. The mechanisms underlying the nitroxides protective effect involve (a) the reoxidation of reduced transition metal ions, (b) the selective radical-radical reaction with juglone semiquinone, and possibly (c) under aerobic condition catalytic removal of extra- and intracellular O2.-. The present results suggest also that the cell membrane rather than DNA is the main target of juglone toxicity.
journal_name
Arch Biochem Biophysjournal_title
Archives of biochemistry and biophysicsauthors
Zhang R,Hirsch O,Mohsen M,Samuni Adoi
10.1006/abbi.1994.1323subject
Has Abstractpub_date
1994-08-01 00:00:00pages
385-91issue
2eissn
0003-9861issn
1096-0384pii
S0003986184713233journal_volume
312pub_type
杂志文章abstract：:A numerical method was applied to a system of differential rate equations describing the monomer-dimer-inhibitor (M-D-I) interaction involving human immunodeficiency virus type 1 protease and a peptidomimetic, competitive inhibitor. Two pairs of progress curves were obtained, one involving the M-D interaction and the ...
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pub_type： 杂志文章
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pub_type： 杂志文章
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pub_type： 杂志文章,评审
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journal_title：Archives of biochemistry and biophysics
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pub_type： 杂志文章
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
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更新日期：1988-05-01 00:00:00
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
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更新日期：1988-05-15 00:00:00
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
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更新日期：2001-01-01 00:00:00
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journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1993.1025
更新日期：1993-01-01 00:00:00
abstract：:The oxidation of 2-(methylseleno)benzanilide and 2-selenylbenzanilide, metabolites of the antioxidant drug ebselen, was examined in reactions catalyzed by rat, pig, and guinea pig liver microsomes and in perfused rat liver. Microsomes from all three species catalyzed NADPH- and oxygen-dependent oxidation of the seleni...
journal_title：Archives of biochemistry and biophysics
pub_type： 杂志文章
doi：10.1006/abbi.1995.1031
更新日期：1995-01-10 00:00:00
