Ascorbic acid (AA) and dehydroascorbic acid (DHA) are known to have protective effects in experimental central nerve system disorder models such as stroke, ischemia, and epileptic seizures. The present study was conducted to examine the protective effect of AA and DHA on kainic acid (KA) neurotoxicity using organotypic hippocampal slice cultures (OHSC). Protective effects of AA and DHA on KA-induced cell death were evaluated by analyzing caspase-3. In addition, to determine if the prooxidant effect of AA is related to iron, the effect of AA on cell death was examined using desferrioxamine (DFO), an iron chelator. After 12h-KA treatment, significant delayed neuronal death was detected in CA3 region, but not in CA1. The AA (500 micrometer) and DHA (100 and 500 micrometer) pretreatments significantly prevented cell death by inhibiting caspase-3 activation in CA3 region. In the concentration of 1,000 micrometer, however, AA pretreatment might have prooxidant effect, but AA-induced oxidative reaction is mainly not related to transition metal ions. These data showed that the pretreatments of intermediate-dose AA and DHA protected KA-induced neuronal damage in OHSCs and co-pretreatment of AA and DFO did not affect cell death except for a few cases. These data suggest that both AA and DHA pretreatment have antioxidant or prooxidant effect depending on doses treated on KA-induced neuronal injury and the possible prooxidant effect of AA may not depend on the Fenton reaction.
Ascorbic Acid ; Caspase 3 ; Cell Death ; Deferoxamine ; Dehydroascorbic Acid ; Epilepsy ; Ions ; Iron ; Ischemia ; Kainic Acid ; Neurons ; Stroke

A high performance liquid chromatography (HPLC) paired with UV-vis detection method to determine ascorbic acid and its oxidation product, dehydroascorbic acid, in human plasma was developed. Ascorbic acid in human plasma was extracted and stabilized using 10% metaphosphoric acid, and was analyzed by a Symmetry C18 column with 5 mM Hexadecyltrimethylammonium bromide and 50 mM KH2PO4 solution as the mobile phase (1.0 mL/min flow rate). Isoascorbic acid served as the internal standard and ultraviolet detector wavelength was 254 nm and 265 nm. Dehydroascorbic acid concentration was calculated from the differences in ascorbic acid concentration before and after reduction by dithiothreitol reagent. Quantification for ascorbic acid in human plasma was linear from 1–100 µg/mL. The inter- and intra-day precisions and accuracy were determined and the results were found to be within ±15%. This method was successfully applied to a human pharmacokinetic study of ascorbic acid as well as dehydroascorbic acid after oral administration of 4,000 mg vitamin C tablets to healthy Korean volunteers.
Administration, Oral ; Ascorbic Acid* ; Chromatography, High Pressure Liquid ; Chromatography, Liquid ; Dehydroascorbic Acid* ; Dithiothreitol ; Humans* ; Plasma* ; Tablets ; Volunteers

OBJECTIVETo compare the influence of different Bupleurun chinense composition to the degree of hepatotoxicity damage to rats and oxidative damage mechanism.

METHODTo successively lavage alcohol extracted and water extracted B. chinense composition to rats for 30 days, the general conditions were observed and the related index of liver function, the content of total-SH in serum, the content of MDA, the activity of SOD and the content and activity of GSH and GSH-Px in serum and liver tissue were detected.

RESULTAlcohol and water extracted B. chinense composition all could induce the increases of the activity of ALT and AST in serum, liver weight and the ratio of liver to body, and the content of MDA and induce the decreses of the content of total -SH in serum, the content of GSH, and the activity of SOD and GSH-Px in serum and liver tissue. The above-mentioned changes gradually aggravated with dose increasing, and there was significant difference compared with control group with distilled water.

CONCLUSIONThe different B. chinense composition all can induce hepatotoxicity damage, and the channel of hepatic damage is related with the peroxidative damage mechanism. The degree of hepatotoxicity damage caused by the alcohol extracted composition is more serious than that by the water extracted composition.

Animals ; Bupleurum ; chemistry ; Dehydroascorbic Acid ; analogs & derivatives ; metabolism ; Female ; Liver ; drug effects ; enzymology ; metabolism ; Male ; Oxidative Stress ; drug effects ; Plant Extracts ; administration & dosage ; toxicity ; Random Allocation ; Rats ; Rats, Wistar ; Superoxide Dismutase ; metabolism

Pro-oxidant properties of ascorbate have been studied with uses of brain tissues and neuronal cells. Here we address potential mechanism of ascorbate coupling with glutamate to generate oxidative stress, and the role which oxidized ascorbate (dehydroascorbate) transport plays in oxidative neuronal injury. Ascorbate in neurones can be depleted by adding glutamate in culture medium since endogenous ascorbate can be exchanged with glutamate, which enhances ascorbate/ dehydroascorbate transport by depleting ascorbate in the neurons with the glutamate-heteroexchange. However, ascorbate is known readily being oxidized to dehydroascorbate in the medium. Glutamate enhanced the dehydroascorbate uptake by cells via a glucose transporter (GLUT) from extracellular region, and cytosolic dehydroascorbate enhanced lipid peroxide production and reduced glutathione (GSH) concentrations. Iso-ascorbate, the epimer of ascorbate was ineffective in generating the oxidative stress. These observations support the current concept that the high rates of dehydroascorbate transport via a GLUT after the release of ascorbate by glutamate leads to peroxidation, the role of glutamate on ascorbate/ dehydroascorbate recycling being critical to induce neuronal death via an oxidative stress in the brain injury.
Animals ; Ascorbic Acid/analogs & derivatives/pharmacology ; Biological Transport/drug effects ; Cerebral Cortex/*drug effects/*metabolism ; Cytochalasin B/pharmacology ; Dehydroascorbic Acid/*metabolism ; Glutamic Acid/*pharmacology ; Glutathione/metabolism ; In Vitro ; Lipid Peroxidation/*drug effects ; Male ; Oxidation-Reduction/drug effects ; Oxidative Stress/drug effects ; Rats ; Rats, Sprague-Dawley ; Thiobarbituric Acid Reactive Substances/metabolism

Ischemic stroke results in the diverse phathophysiologies including blood brain barrier (BBB) disruption, brain edema, neuronal cell death, and synaptic loss in brain. Vitamin C has known as the potent anti-oxidant having multiple functions in various organs, as well as in brain. Dehydroascorbic acid (DHA) as the oxidized form of ascorbic acid (AA) acts as a cellular protector against oxidative stress and easily enters into the brain compared to AA. To determine the role of DHA on edema formation, neuronal cell death, and synaptic dysfunction following cerebral ischemia, we investigated the infarct size of ischemic brain tissue and measured the expression of aquaporin 1 (AQP-1) as the water channel protein. We also examined the expression of claudin 5 for confirming the BBB breakdown, and the expression of bcl 2 associated X protein (Bax), caspase-3, inducible nitric oxide synthase (iNOS) for checking the effect of DHA on the neurotoxicity. Finally, we examined postsynaptic density protein-95 (PSD-95) expression to confirm the effect of DHA on synaptic dysfunction following ischemic stroke. Based on our findings, we propose that DHA might alleviate the pathogenesis of ischemic brain injury by attenuating edema, neuronal loss, and by improving synaptic connection.
Aquaporins ; Aquaporin 1 ; Ascorbic Acid ; bcl-2-Associated X Protein ; Blood-Brain Barrier ; Brain ; Brain Edema* ; Brain Injuries ; Brain Ischemia* ; Caspase 3 ; Cell Death ; Claudin-5 ; Dehydroascorbic Acid* ; Edema ; Neurons ; Nitric Oxide Synthase Type II ; Oxidative Stress ; Post-Synaptic Density ; Stroke

Anti-Infective Agents, Local ; therapeutic use ; Biosensing Techniques ; Chlorhexidine ; therapeutic use ; Chlorine Compounds ; therapeutic use ; Chromatography, Gas ; Dehydroascorbic Acid ; therapeutic use ; Dental Disinfectants ; therapeutic use ; Halitosis ; diagnosis ; therapy ; Humans ; Hydrogen Peroxide ; therapeutic use ; Mouthwashes ; therapeutic use ; Odorants ; prevention & control ; Oils, Volatile ; therapeutic use ; Oral Hygiene ; instrumentation ; Oxides ; therapeutic use ; Sodium Bicarbonate ; therapeutic use ; Sulfur Compounds ; analysis

OBJECTIVETo study the effects and immunoregulation mechanism of the traditional Mongolian medicine Wuweifengshi capsule on adjuvant arthritis (AA).

METHODWister rats were divided into several groups: normal group, AA model group, Wuweifengshi capsule groups (with low, moderate, high dose of 0.2, 0.4, 0.8 g x kg(-1) x d(-1) respectively), and Zhonglun-5 group (original dose of 1.68 g x kg(-1) x d(-1)). The edema degree, the level of IL-1beta, TNF-alpha, PGE2, NO and MDA and the activity of SOD in serum were detected. Through cell culture, the effects of the medicine on AA rat's splenic cell's multiplication capacity were studied. The influence of celiac macrophage cell culture fluid of AA rats' on C57BL/6J mice thymic cell multiplication capacity under the medicine was evaluated.

RESULTWuweifengshi capsule showed an inhibiting function on the level of IL-1beta, TNF-alpha, PGE2, NO and increased the activity of SOD in serum, but showed no significant influence on MDA. It also inhibited the AA rat's splenic cell's multiplication capacity and the influence of celiac macrophage cell culture fluid of AA rat's on C57BL/6J mice thymic cell multiplication capacity.

CONCLUSIONThe anti-AA effect of Wuweifengshi capsule is possibly due to its inhibition of relevant cytokines and its adjustment of corresponding enzyme's activity and immunization organ's cell multiplication capacity.

Animals ; Arthritis, Experimental ; drug therapy ; immunology ; metabolism ; pathology ; Capsules ; Dehydroascorbic Acid ; analogs & derivatives ; blood ; Dinoprostone ; metabolism ; Disease Models, Animal ; Edema ; drug therapy ; Female ; Interleukin-1beta ; metabolism ; Lymphocytes ; immunology ; metabolism ; Macrophages, Peritoneal ; metabolism ; Male ; Medicine, Mongolian Traditional ; Mice ; Nitric Oxide ; metabolism ; Rats ; Spleen ; cytology ; metabolism ; Superoxide Dismutase ; blood ; Tumor Necrosis Factor-alpha ; metabolism