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Dehydroascorbic acid

About: Dehydroascorbic acid is a research topic. Over the lifetime, 1531 publications have been published within this topic receiving 55457 citations. The topic is also known as: dehydroascorbate & DHAA.


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TL;DR: Iron and selenium are established as opposing mediators of high‐dose ascorbate’s pharmacological activity and suggest that cancer sensitivity to free‐radical therapies depends on mineral bioavailability.
Abstract: High‐dose ascorbate (vitamin C) has shown promising anti‐cancer activity. We sought to distinguish the mechanism of cancer cell ascorbate toxicity between two proposed models: hydrogen peroxide (H2O2) generation by ascorbate itself or glutathione depletion by its oxidized form, dehydroascorbate. Using a combination of metabolic and genetic approaches, we show that ascorbate kills cancer cells through a free radical mechanism that is promoted by iron and suppressed by selenium. High‐dose ascorbate’s metabolic effects and cytotoxicity result from hydrogen peroxide independent of dehydroascorbate. Cytotoxicity further depends on iron via a route distinct from canonical ferroptosis, as the hydrogen peroxide‐detoxifying selenoenzyme GPX1 is critical while the ferroptosis‐suppressing GPX4 is dispensable. Selenium‐mediated protection from ascorbate is powered by NADPH from the pentose phosphate pathway. In a mouse model of glioblastoma, dietary selenium deprivation enhances the efficacy of ascorbate as an anti‐cancer agent. These data establish iron and selenium as opposing mediators of high‐dose ascorbate’s pharmacological activity. More generally, they suggest that cancer sensitivity to free‐radical therapies depends on mineral bioavailability.
Journal ArticleDOI
TL;DR: In this paper , a sensitive and robust ratiometric fluorescence ELISA (RF-ELISA) was constructed for detecting tricaine based on two MnO2 nanoflake-mediated (MnO2 NFs) fluorogenic reactions.
Abstract: Tricaine is a common anesthetic used in the long-distance transport of live fish. Recently, its negative impact on human health has aroused extensive concern. Thus, rapid and reliable techniques for tricaine residue analysis are essential to ensuring the quality of aquatic products. Herein, a specific anti-tricaine monoclonal antibody (Mab) was prepared. Then, a sensitive and robust ratiometric fluorescence ELISA (RF-ELISA) was constructed for detecting tricaine based on two MnO2 nanoflake-mediated (MnO2 NFs) fluorogenic reactions. In the RF-ELISA protocol, MnO2 NFs with oxidase-like activity can trigger the formation of fluorescent 2,3-diaminophenazine (oxOPD) with an emissive peak at 570 nm from non-fluorescent o-phenylenediamine (OPD), while ascorbic acid (AA) can decompose MnO2 NFs to lose their oxidase-mimicking activity, which is accompanied by the oxidation of AA into dehydroascorbic acid (DHAA). The subsequent reaction between the generated DHAA and OPD will result in the production of 3-(1,2-dihydroxy ethyl)furo[3,4-b]quinoxalin-1(3H)-on (DFQ), which has a potent emission peak at 445 nm. By virtue of the alkaline phosphatase (ALP) labeled on the antibody, which can catalyze the production of AA from ascorbic acid 2-phosphate (AAP), the concentration of tricaine can be linked to the variation of the RF signal (F445/F570) via a competitive immunoreaction. After optimization, RF-ELISA displayed a detection limit (LOD) of 0.28 ng/mL toward tricaine (in buffer solution), which was 376-fold lower than that of the traditional colorimetric ELISA. For practical application, the LODs of RF-ELISA for tricaine detection in shrimp and tilapia samples were determined to be 2.8 and 5.6 ng/g, respectively. Recoveries for spiked shrimp and tilapia samples, as well as the validation data from LC-MS/MS, showed that RF-ELISA exhibited good accuracy, precision, and reliability. This RF-ELISA protocol opened up new ways for tricaine and other-target analyses in food safety detection.
Journal ArticleDOI
TL;DR: Prooxidant-antioxidant homeostasis in boars depending on the types of higher nervous activity is studied, and it is shown that the former dominates in the males and the latter in the females.
Abstract: The peculiarities of formation of prooxidant-antioxidant homeostasis (PAG) in boars of different types of higher nervous activity have been studied. Using motor-nutritional techniques, it has been opposed adult boars of the Large White breed aged 24–36 months according to the main types of higher nervous activity (HNA). Four groups of 3 heads each were formed. The first group includes animals of a strong balanced lively (mobile) type; group II includes a strong balanced calm (inert) type; group III includes a strong unbalanced (unrestrained) type; group IV includes a weak type of higher nervous activity. Sperm was received from boars manually, taking into account the total time of ejaculation, dividing the ejaculate into 4 fractions – F1 – the first, F2 – the second, F3 – the third, F4 – the fourth. PAGs in blood and ejaculates of boars were evaluated by the intensity of peroxidation processes (xanthine oxidase, diene conjugates, TBA-active compounds) and antioxidant defense systems (superoxide dismutase, catalase, reduced glutathione, ascorbic acid, vitamin A and vitamin E). Sperm contained higher amounts of diene conjugates and TBA-active complexes (P < 0.05) compared to blood. The second tissue relative to the first one is characterized by a higher level of antioxidant defense: catalase activity, concentration of ascorbic acid, vitamin A and vitamin E. The process of PAG formation in the tissues of boars depends on the type of higher nervous activity (HNA). Thus, in individuals of a strong balanced lively and calm type, the course of peroxidation processes is somewhat slower because of a lower concentration of diene conjugates and TBA-active complexes. It was determined the fact that in blood and sperm of boars of strong unbalanced and weak types of HNA the course of peroxidation is more intense, the antioxidant defense system is at a lower level that is connected with less superoxide dismutase activity (P < 0.05), concentration of ascorbic acid (P < 0.001), vitamin A (P < 0.01–0.001), and vitamin E (P < 0.001). In the second and third fractions of ejaculate of boars, the PAG is shifted in the direction of probable acceleration of peroxidation processes, especially in strong unbalanced and weak types of HNA because of a higher concentration of diene conjugates, dehydroascorbic acid. Animals of a strong balanced lively and calm types of HNA are characterized by a higher level of antioxidant defence – catalase activity, superoxide dismutase, reduced glutathione, ascorbic acid and vitamin E. In the first and fourth fractions of ejaculate, peroxidation processes are slower and there is no superoxide dismutase activity and the amount of vitamin A and vitamin E.
DOI
12 Feb 2009
TL;DR: In this paper, the importance of the state of glass or rubber of BSA on the rate and extent of polymerisation, protein solubility, colour and SDS PAGE patterns in the presence and absence of ascorbic acid, diketogulonic acid and dehydroascorbic acid was investigated.
Abstract: Showing the occurrence of glass/rubber transition in bovine serum albumin (a globular protein) at low moisture levels and the occurrence of Maillard crosslinking in gelatin in previous works, the importance of the state of glass or rubber of BSA on the rate and extent of polymerisation, protein solubility, colour and SDS PAGE patterns in the presence and absence of ascorbic acid, diketogulonic acid and dehydroascorbic acid was investigated. BSA on storage with Ascorbic acid and its degradation products at low moisture contents (8.3% and 19.1%) at a relatively low temperature (40oC) can undergo chemical changes resulting in marked increase in molecular weight, solubility decrease and formation of browning colour. The glassy state data established the occurrence of chemical changes (Maillard crosslinking and disulfide crosslinking) in the BSA system on storage below its glass transition temperature.

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202323
202240
202114
202030
201919
201815