| Antioxidant and neutrophil-inhibiting properties of new 2-O-methyl-6-(alkylthio)ascorbic acid derivatives. | |
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MedLine Citation:
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PMID: 8258824 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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A series of new 6-(alkylthio)ascorbic acids was synthesized, and their inhibitory effects on lipid peroxidation and the oxidative burst of human neutrophils were tested. Of 12 structurally different lipophilic ascorbic acid derivatives 6-S-n-hexadecyl-2-O-methyl-6-deoxy-6-thio-L-ascorbic acid (7b; B-003) inhibited the Fe2+/ADP-induced lipid peroxidation of rat liver microsomes with an IC50 value of 2 microM. In human neutrophils, 7b most potently inhibited the fMLP-induced oxidative burst in a cell density-dependent manner with an IC50 value of 0.6 microM at 5 x 10(5) cells/mL. Shorter alkyl chain lengths decreased the inhibitory potency for both lipid peroxidation and oxidative burst, but in general no correlation was found between the two parameters. Likewise, 6-S-n-hexadecyl-3-O-methyl-6-thio-L-ascorbic acid (7c; B-015), the regioisomer of 7b, was a potent antioxidant but did not affect the oxidative burst. Since superoxide anions generated by xanthine/xanthine oxidase were not quenched by 7b, it became evident that its target was somewhere between receptor stimulation and NADPH-oxidase activation. By measuring the cellular concentrations of 7b and 7c, an accumulation of the first was found explaining its potency and the dependence on cell density. Expecting a pKa value of 3.3 for 7b and 7.7 for 7c a protonophore action of 7b was likely and could be verified by the drop in intracellular pH (pHi) which did not occur with 7c. Ionophores such as nigericin, CCCP, or propionic acid also lowered the pHi but did not inhibit the oxidative burst, indicating that the pHi drop was not the cause for this inhibition. 7b also strongly inhibited the fMLP-induced secretion of azurophilic (IC50 = 7 microM) and specific (IC50 = 2.5 microM) granules. |
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Authors:
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E Schmid; V Figala; D Roth; V Ullrich |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Journal of medicinal chemistry Volume: 36 ISSN: 0022-2623 ISO Abbreviation: J. Med. Chem. Publication Date: 1993 Dec |
Date Detail:
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Created Date: 1994-01-18 Completed Date: 1994-01-18 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 9716531 Medline TA: J Med Chem Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 4021-9 Citation Subset: IM |
Affiliation:
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Faculty of Biology, University of Konstanz, FRG. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Antioxidants / chemical synthesis, chemistry, pharmacology* Ascorbic Acid / analogs & derivatives* Humans Lipid Peroxidation / drug effects* Membrane Potentials / drug effects Microsomes, Liver / drug effects, metabolism Neutrophils / drug effects*, metabolism Rats Rats, Wistar Respiratory Burst / drug effects Structure-Activity Relationship Superoxide Dismutase / biosynthesis |
| Chemical | |
Reg. No./Substance:
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0/Antioxidants; 50-81-7/Ascorbic Acid; EC 1.15.1.1/Superoxide Dismutase |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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