Abstract
lsoflavonoids, formononetin, 9,10-dimethoxypterocarpan 3-O-beta-D-glucoside, ononin, calycosin 7-O-glc and calycosin, were isolated from the roots of Astragalus mongholicus Bunge (Leguminosae). The neuroprotective roles and direct antioxidant effects of these isoflavonoids were investigated by using PC12 cell model and DPPH (1,1-diphenyl-2-picrylhydrazyl) assay. Formononetin, ononin and calycosin were found inhibiting glutamate-induced cell injury, with an estimated 50% effective concentration (EC50) of 0.027 microg/ml, 0.047 microg/ml and 0.031 microg/ml, respectively. Pretreatment with them increased the activities of antioxidant enzymes, including superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and prevented the release of lactate dehydrogenase (LDH) in glutamate-injured PC12 cells. On the other hand, calycosin 7-O-glc and calycosin showed more scavenging activity to DPPH radicals than formononetin in the cell-free system. The inconsistency between the neuroprotective capabilities of isoflavonoids and their directly scavenging activity to DPPH radicals indicated that formononetin, ononin and calycosin probably depended on increasing endogenous antioxidant and stabilizing the cells' membrane structures to inhibit the cell damage induced by glutamate.
MeSH terms
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Animals
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Astragalus Plant / chemistry*
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Biphenyl Compounds / pharmacology
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Cell Survival / drug effects
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Cell Survival / physiology
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Dose-Response Relationship, Drug
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Drug Evaluation, Preclinical / methods
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Drugs, Chinese Herbal
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Ethanol
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Formazans / pharmacology
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Free Radical Scavengers / chemistry
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Free Radical Scavengers / isolation & purification
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Free Radical Scavengers / pharmacology
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Glutamic Acid / adverse effects*
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Glutamic Acid / metabolism
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Glutathione / drug effects
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Glutathione / physiology
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Glutathione Peroxidase / drug effects
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Glutathione Peroxidase / physiology
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Hydrazines / pharmacology
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Isoflavones / chemistry*
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Isoflavones / isolation & purification
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Isoflavones / pharmacology*
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L-Lactate Dehydrogenase / antagonists & inhibitors
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L-Lactate Dehydrogenase / drug effects
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L-Lactate Dehydrogenase / metabolism
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Neurons / cytology
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Neurons / drug effects
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Neurons / metabolism
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PC12 Cells*
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Picrates
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Plant Extracts / chemistry
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Plant Extracts / isolation & purification
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Plant Extracts / pharmacology
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Plant Roots / chemistry
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Rats
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Superoxide Dismutase / drug effects
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Superoxide Dismutase / physiology
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Tetrazolium Salts / pharmacology
Substances
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Biphenyl Compounds
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Drugs, Chinese Herbal
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Formazans
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Free Radical Scavengers
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Hydrazines
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Isoflavones
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Picrates
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Plant Extracts
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Tetrazolium Salts
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MTT formazan
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Ethanol
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Glutamic Acid
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1,1-diphenyl-2-picrylhydrazyl
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L-Lactate Dehydrogenase
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Glutathione Peroxidase
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Superoxide Dismutase
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Glutathione