scholarly journals The oxidation of dehydroascorbic acid and 2,3-diketogulonate by distinct reactive oxygen species

2018 ◽  
Vol 475 (21) ◽  
pp. 3451-3470 ◽  
Author(s):  
Rebecca A. Dewhirst ◽  
Stephen C. Fry
Keyword(s):  
Reactive Oxygen Species ◽  
Ascorbic Acid ◽  
Hydroxyl Radicals ◽  
Reactive Oxygen ◽  
Dehydroascorbic Acid ◽  
Oxidation Products ◽  
Oxygen Species ◽  
H2o2 Treatment ◽  
Fold Excess

l-Ascorbate, dehydro-l-ascorbic acid (DHA), and 2,3-diketo-l-gulonate (DKG) can all quench reactive oxygen species (ROS) in plants and animals. The vitamin C oxidation products thereby formed are investigated here. DHA and DKG were incubated aerobically at pH 4.7 with peroxide (H2O2), ‘superoxide’ (a ∼50 : 50 mixture of and ), hydroxyl radicals (•OH, formed in Fenton mixtures), and illuminated riboflavin (generating singlet oxygen, 1O2). Products were monitored electrophoretically. DHA quenched H2O2 far more effectively than superoxide, but the main products in both cases were 4-O-oxalyl-l-threonate (4-OxT) and smaller amounts of 3-OxT and OxA + threonate. H2O2, but not superoxide, also yielded cyclic-OxT. Dilute Fenton mixture almost completely oxidised a 50-fold excess of DHA, indicating that it generated oxidant(s) greatly exceeding the theoretical •OH yield; it yielded oxalate, threonate, and OxT. 1O2 had no effect on DHA. DKG was oxidatively decarboxylated by H2O2, Fenton mixture, and 1O2, forming a newly characterised product, 2-oxo-l-threo-pentonate (OTP; ‘2-keto-l-xylonate’). Superoxide yielded negligible OTP. Prolonged H2O2 treatment oxidatively decarboxylated OTP to threonate. Oxidation of DKG by H2O2, Fenton mixture, or 1O2 also gave traces of 4-OxT but no detectable 3-OxT or cyclic-OxT. In conclusion, DHA and DKG yield different oxidation products when attacked by different ROS. DHA is more readily oxidised by H2O2 and superoxide; DKG more readily by 1O2. The diverse products are potential signals, enabling organisms to respond appropriately to diverse stresses. Also, the reaction-product ‘fingerprints’ are analytically useful, indicating which ROS are acting in vivo.

scholarly journals [11C]Ascorbic and [11C]dehydroascorbic acid, an endogenous redox pair for sensing reactive oxygen species using positron emission tomography

2016 ◽  
Vol 52 (27) ◽  
pp. 4888-4890 ◽  
Author(s):  
V. N. Carroll ◽  
C. Truillet ◽  
B. Shen ◽  
R. R. Flavell ◽  
X. Shao ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Positron Emission Tomography ◽  
Ascorbic Acid ◽  
Reactive Oxygen ◽  
Dehydroascorbic Acid ◽  
Emission Tomography ◽  
Oxygen Species ◽  
Redox Pair ◽  
Positron Emission

We report the radiosynthesis of an endogenous redox pair, [11C]ascorbic acid and [11C]dehydroascorbic acid and their application to ROS sensing.

scholarly journals Detection Technologies for Reactive Oxygen Species: Fluorescence and Electrochemical Methods and Their Applications

Biosensors ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 30
Author(s):  
Surachet Duanghathaipornsuk ◽  
Eveline J. Farrell ◽  
Ana C. Alba-Rubio ◽  
Piotr Zelenay ◽  
Dong-Shik Kim
Keyword(s):  
Reactive Oxygen Species ◽  
Hydroxyl Radicals ◽  
Reactive Oxygen ◽  
Electrochemical Methods ◽  
Oxygen Species ◽  
Environmental Processes ◽  
Inorganic Molecules ◽  
Detection Technologies

Reactive oxygen species (ROS) have been found in plants, mammals, and natural environmental processes. The presence of ROS in mammals has been linked to the development of severe diseases, such as diabetes, cancer, tumors, and several neurodegenerative conditions. The most common ROS involved in human health are superoxide (O2•−), hydrogen peroxide (H2O2), and hydroxyl radicals (•OH). Organic and inorganic molecules have been integrated with various methods to detect and monitor ROS for understanding the effect of their presence and concentration on diseases caused by oxidative stress. Among several techniques, fluorescence and electrochemical methods have been recently developed and employed for the detection of ROS. This literature review intends to critically discuss the development of these techniques to date, as well as their application for in vitro and in vivo ROS detection regarding free-radical-related diseases. Moreover, important insights into and further steps for using fluorescence and electrochemical methods in the detection of ROS are presented.

scholarly journals Targeting autophagy enhances atezolizumab-induced mitochondria-related apoptosis in osteosarcoma

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Zhuochao Liu ◽  
Hongyi Wang ◽  
Chuanzhen Hu ◽  
Chuanlong Wu ◽  
Jun Wang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Antitumor Immunity ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Specific Monoclonal Antibody ◽  
Osteosarcoma Cells ◽  
Jnk Pathway ◽  
In Vivo Experiments

AbstractIn this study, we identified the multifaceted effects of atezolizumab, a specific monoclonal antibody against PD-L1, in tumor suppression except for restoring antitumor immunity, and investigated the promising ways to improve its efficacy. Atezolizumab could inhibit the proliferation and induce immune-independent apoptosis of osteosarcoma cells. With further exploration, we found that atezolizumab could impair mitochondria of osteosarcoma cells, resulting in increased release of reactive oxygen species and cytochrome-c, eventually leading to mitochondrial-related apoptosis via activating JNK pathway. Nevertheless, the excessive release of reactive oxygen species also activated the protective autophagy of osteosarcoma cells. Therefore, when we combined atezolizumab with autophagy inhibitors, the cytotoxic effect of atezolizumab on osteosarcoma cells was significantly enhanced in vitro. Further in vivo experiments also confirmed that atezolizumab combined with chloroquine achieved the most significant antitumor effect. Taken together, our study indicates that atezolizumab can induce mitochondrial-related apoptosis and protective autophagy independently of the immune system, and targeting autophagy is a promising combinatorial approach to amplify its cytotoxicity.

scholarly journals Plant Extracts and Reactive Oxygen Species as Two Counteracting Agents with Anti- and Pro-Obesity Properties

2019 ◽  
Vol 20 (18) ◽  
pp. 4556 ◽  
Author(s):  
Hanna Zielinska-Blizniewska ◽  
Przemyslaw Sitarek ◽  
Anna Merecz-Sadowska ◽  
Katarzyna Malinowska ◽  
Karolina Zajdel ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Plant Extracts ◽  
Complex Disease ◽  
Reactive Oxygen ◽  
Complementary Therapy ◽  
Biologically Active ◽  
Mitochondrial Activity ◽  
Oxygen Species

Obesity is a complex disease of great public health significance worldwide: It entails several complications including diabetes mellitus type 2, cardiovascular dysfunction and hypertension, and its prevalence is increasing around the world. The pathogenesis of obesity is closely related to reactive oxygen species. The role of reactive oxygen species as regulatory factors in mitochondrial activity in obese subjects, molecules taking part in inflammation processes linked to excessive size and number of adipocytes, and as agents governing the energy balance in hypothalamus neurons has been examined. Phytotherapy is the traditional form of treating health problems using plant-derived medications. Some plant extracts are known to act as anti-obesity agents and have been screened in in vitro models based on the inhibition of lipid accumulation in 3T3-L1 cells and activity of pancreatic lipase methods and in in vivo high-fat diet-induced obesity rat/mouse models and human models. Plant products may be a good natural alternative for weight management and a source of numerous biologically-active chemicals, including antioxidant polyphenols that can counteract the oxidative stress associated with obesity. This review presents polyphenols as natural complementary therapy, and a good nutritional strategy, for treating obesity without serious side effects.

scholarly journals Costunolide Induces Apoptosis via the Reactive Oxygen Species and Protein Kinase B Pathway in Oral Cancer Cells

2021 ◽  
Vol 22 (14) ◽  
pp. 7509
Author(s):  
Hai Huang ◽  
Jun-Koo Yi ◽  
Su-Geun Lim ◽  
Sijun Park ◽  
Haibo Zhang ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Cycle ◽  
Flow Cytometry ◽  
Oral Cancer ◽  
Cancer Cells ◽  
Reactive Oxygen ◽  
Migration And Invasion ◽  
Oxygen Species ◽  
Oral Cancer Cells

Oral cancer (OC) has been attracted research attention in recent years as result of its high morbidity and mortality. Costunolide (CTD) possesses potential anticancer and bioactive abilities that have been confirmed in several types of cancers. However, its effects on oral cancer remain unclear. This study investigated the potential anticancer ability and underlying mechanisms of CTD in OC in vivo and in vitro. Cell viability and anchorage-independent colony formation assays were performed to examine the antigrowth effects of CTD on OC cells; assessments for migration and invasion of OC cells were conducted by transwell; Cell cycle and apoptosis were investigated by flow cytometry and verified by immunoblotting. The results revealed that CTD suppressed the proliferation, migration and invasion of oral cancer cells effectively and induced cell cycle arrest and apoptosis; regarding the mechanism, CTD bound to AKT directly by binding assay and repressed AKT activities through kinase assay, which thereby downregulating the downstream of AKT. Furthermore, CTD remarkably promotes the generation of reactive oxygen species by flow cytometry assay, leading to cell apoptosis. Notably, CTD strongly suppresses cell-derived xenograft OC tumor growth in an in vivo mouse model. In conclusion, our results suggested that costunolide might prevent progression of OC and promise to be a novel AKT inhibitor.

CSIG-21. 5-ALA PDT AND TARGETING MEK/ERK SIGNALING ELICITS SYNERGISTIC ANTITUMOR EFFECTS IN DIFFUSE MIDLINE GLIOMA

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi37-vi37
Author(s):  
Gabrielle Price ◽  
Daniel Rivera ◽  
Alexandros Bouras ◽  
Constantinos Hadjipanayis
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Proliferation ◽  
Aminolevulinic Acid ◽  
Tumor Therapy ◽  
Unmet Need ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Antitumor Effects ◽  
Genetically Engineered Mouse Model

Abstract Diffuse midline gliomas (DMGs) are highly invasive, unresectable tumors in children. To date, there is no effective treatment for DMGs. Fractionated radiotherapy (RT), currently the standard of care, has provided limited disease control. Current obstacles to treatment include the blood brain barrier (BBB) that limits systemic drug delivery, tumor therapy resistance, and brainstem infiltration. Given the unmet need for more effective DMG treatments, photodynamic therapy (PDT), with the precursor photosensitizing agent 5-aminolevulinic acid (5-ALA), is an oncologic treatment that holds promise. 5-ALA PDT of tumors occurs by targeting tumor cells that accumulate the 5-ALA metabolite, protoporphyrin IX (PPIX), with 635 nm light to create deadly reactive oxygen species (ROS). We explore the synergism of 5-ALA PDT with the MEK inhibitor, trametinib, since the RAS/MEK signaling pathway regulates tumor cell proliferation and survival and has been shown to therapeutically enhance PDT in select tumor models. We demonstrated that sub-micromolar levels of 5-ALA PDT and nanomolar levels of trametinib successfully decrease cell proliferation and induce apoptosis in multiple DMG cell lines. Cell viability assays revealed that drug response differs based on the histone mutation (H3.1 or H3.3) of the line. Mechanisms of decreased cell survival involves the generation of reactive oxygen species that induces programmed cell death. Through the use of a DMG genetically engineered mouse model, we also found 5-ALA PDT to induce apoptosis in vivo. The synergistic effects of MEK inhibition and 5-ALA PDT in vitro and apoptotic effects of 5-ALA PDT in vivo, highlights the potential therapeutic efficacy of this treatment modality.

Mitochondrial Adenosine Triphosphate–regulated Potassium Channel Opening Acts as a Trigger for Isoflurane-induced Preconditioning by Generating Reactive Oxygen Species

2003 ◽  
Vol 98 (4) ◽  
pp. 935-943 ◽  
Author(s):  
Katsuya Tanaka ◽  
Dorothee Weihrauch ◽  
Lynda M. Ludwig ◽  
Judy R. Kersten ◽  
Paul S. Pagel ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Infarct Size ◽  
Adenosine Triphosphate ◽  
Superoxide Anion ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Superoxide Anion Production ◽  
Channel Opening ◽  
Anion Production

Background Whether the opening of mitochondrial adenosine triphosphate-regulated potassium (K(ATP)) channels is a trigger or an end effector of anesthetic-induced preconditioning is unknown. We tested the hypothesis that the opening of mitochondrial K(ATP) channels triggers isoflurane-induced preconditioning by generating reactive oxygen species (ROS) in vivo. Methods Pentobarbital-anesthetized rabbits were subjected to a 30-min coronary artery occlusion followed by 3 h reperfusion. Rabbits were randomly assigned to receive a vehicle (0.9% saline) or the selective mitochondrial K(ATP) channel blocker 5-hydroxydecanoate (5-HD) alone 10 min before or immediately after a 30-min exposure to 1.0 minimum alveolar concentration (MAC) isoflurane. In another series of experiments, the fluorescent probe dihydroethidium was used to assess superoxide anion production during administration of 5-HD or the ROS scavengers N-acetylcysteine or N-2-mercaptopropionyl glycine (2-MPG) in the presence or absence of 1.0 MAC isoflurane. Myocardial infarct size and superoxide anion production were measured using triphenyltetrazolium staining and confocal fluorescence microscopy, respectively. Results Isoflurane (P < 0.05) decreased infarct size to 19 +/- 3% (mean +/- SEM) of the left ventricular area at risk as compared to the control (38 +/- 4%). 5-HD administered before but not after isoflurane abolished this beneficial effect (37 +/- 4% as compared to 24 +/- 3%). 5-HD alone had no effect on infarct size (42 +/- 3%). Isoflurane increased fluorescence intensity. Pretreatment with N-acetylcysteine, 2-MPG, or 5-HD before isoflurane abolished increases in fluorescence, but administration of 5-HD after isoflurane only partially attenuated increases in fluorescence produced by the volatile anesthetic agent. Conclusions The results indicate that mitochondrial K(ATP) channel opening acts as a trigger for isoflurane-induced preconditioning by generating ROS in vivo.

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