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Introduction to Oxidative (Eu)stress in Exercise Physiology
Published in James N. Cobley, Gareth W. Davison, Oxidative Eustress in Exercise Physiology, 2022
Gareth W. Davison, James N. Cobley
Superoxide is a commonly known oxygen-centred free radical. The reduction of a single electron to an O2 molecule produces the superoxide anion. is relatively unreactive with non-radical species in comparison to other radical types (e.g., hydroxyl radical); however, if is generated near the site of any biochemical molecule it can be damaging. The reactivity of in aqueous solutions is more likely to occur in vivo (Halliwell and Gutteridge, 2015). In this environment, can act as a base, accepting a proton to form the hydroperoxyl radical (HO2.). The pKa for this reaction is 4.8, indicating that approximately only 1% of is in the form at physiological pH (Pryor, 1986). However, there may be more at comparatively acidic membrane nanodomains. under a normal metabolic response is dismutated by SOD, which can increase the rate of intracellular dismutation by a factor of 10−9 M−1s−1 to form hydrogen peroxide (H2O2) (Chance et al., 1979), as shown in equation 1.1:
Application of Next-Generation Plant-Derived Nanobiofabricated Drugs for the Management of Tuberculosis
Published in Richard L. K. Glover, Daniel Nyanganyura, Rofhiwa Bridget Mulaudzi, Maluta Steven Mufamadi, Green Synthesis in Nanomedicine and Human Health, 2021
Charles Oluwaseun Adetunji, Olugbenga Samuel Michael, Muhammad Akram, Kadiri Oseni, Ajayi Kolawole Temidayo, Osikemekha Anthony Anani, Akinola Samson Olayinka, Olerimi Samson E, Wilson Nwankwo, Iram Ghaffar, Juliana Bunmi Adetunji
Peroxidation of lipid is known to take place commonly in the membrane of the cells and organelles due to their membrane composition. The commonest targets include unsaturated lipids and cholesterol. Common inducers of lipid peroxidation include the reactive oxygen species (ROS) such as hydroxyl radical, singlet oxygen and hydroperoxyl radical. Lipid peroxidation does not involve the damage of lipids alone, but also protein and nucleic acid. Several studies have showed that several metal oxide nanoparticles have the potential to exhibit spontaneous ROS production; this can cause the cell to enter the state of oxidative stress. If the cellular antioxidant defence is low, it can lead to the damage of cellular components of proteins, nucleic acid and lipids (Premanathan et al., 2011). The generation of the fatty acid from the breakdown of lipids can cause the activation of lipid peroxidase, which will initiate a chain reaction that will disrupt the membrane of organelles and cellular membrane. This can result in cell death (Premanathan et al., 2011).
Influence of Air on Essential Oil Constituents
Published in K. Hüsnü Can Başer, Gerhard Buchbauer, Handbook of Essential Oils, 2020
Darija Gajić, Gerhard Buchbauer
In conclusion, the study of prenol as a geraniol model system offered a brief comparison to a linalool oxidation mechanism. The main difference was presented regarding both propagation steps (radical chain transfer and the addition of O2) that were marked as exergonic. Additionally, besides from the usual chain transfer reaction, peroxyl radicals deriving from geraniol can also undergo intramolecular hydrogen abstraction. This phase is then followed by fragmentation and release of a hydroperoxyl radical. This radical is observed as an alternative chain transfer agent and the process itself was considered to be favored compared to the classical intermolecular hydrogen abstraction. Notably, hydrogen peroxide occurs as a side product of both of these processes. Nevertheless, when a full system of geraniol is used instead of the geraniol model molecule, cis/trans isomerization, giving neral and geranial, must be considered too. The expected autoxidation pathway of geraniol will thus be observed further on.
Investigation of the effects of three different generations of fluoroquinolone derivatives on antioxidant and immunotoxic enzyme levels in different rat tissues
Published in Drug and Chemical Toxicology, 2022
The shifting of the balance between oxidants/antioxidants in favor of oxidants is called oxidative stress (Birben et al.2012). Oxidative stress is caused by releasing of reactive oxygen species (ROS) due to the toxic effects of drugs (Hosohata 2016; Yew et al.2018). ROS can be divided into two groups as radicals and non-radicals according to their state of electrons (Chowdhury and Saikia 2020). While free radicals form superoxide (O2-•), hydroxyl (HO•-), hydroperoxyl (HOO•), peroxyl (ROO•), and alkoxyl (RO•) radicals; non-radicals form hydrogen peroxide (H2O2), hypochlorous acid (HClO), ozone (O3), and singlet oxygen (1O2) (Bratovcic 2020). Various metabolic diseases can occur together with oxidative stress as a result of the presence of endogenous and exogenous ROS in the body (Dogan et al.2018).
Charge effect of water-soluble porphyrin derivatives as a prototype to fight infections caused by Acinetobacter baumannii by aPDT approaches
Published in Biofouling, 2022
Carolina da Silva Canielles Caprara, Livia da Silva Freitas, Bernardo Almeida Iglesias, Lara Beatriz Ferreira, Daniela Fernandes Ramos
Therefore, in this study, the presence of hydroxyl (•OH), superoxide (O2•−), and hydroperoxyl (•OOH) radical species scavengers maintained or reduced the porphyrin MIC values by four times. Regarding the non-enzymatic antioxidant — ascorbic acid and ethylenediamine tetra-acetic acid — which are involved in protecting cell membranes from lipoperoxidation and chelating activity, respectively (da Fonseca et al. 2021), a significant increase was observed in porphyrin MIC when associated with the subinhibitory concentration of these compounds. This indicates that the nonionizing radiation associated with the photosensitizer (H2TMePyP+) promotes free radical production, inducing the antimicrobial effect against A. baumannii; these results are quite similar to other bacterial species reported elsewhere (Soares Lopes et al. 2019; Rossi et al. 2020; da Fonseca et al. 2021; Jornada et al. 2021; Rossi et al. 2021). In general, given the data obtained in Table 2, it is possible to infer that in addition to 1O2 species, radical species generated by Type-I mechanisms are also present during the photoinactivation process, leading us to believe that these species contribute to destabilizing the cell membrane, aided by the action of the chelator EDTA, as observed by the results obtained.
Emergency management of chlorine gas exposure – a systematic review
Published in Clinical Toxicology, 2019
Alice Huynh Tuong, Thomas Despréaux, Thomas Loeb, Jérôme Salomon, Bruno Mégarbane, Alexis Descatha
At high concentrations, ascorbate may act as a pro-oxidant by reducing transition metals, inducing a variety of radical reactions like Fenton’s [41]. Fenton reactions rely on the oxidation of an iron(II) atom that leads to the creation of hydroxyl radicals and iron(III). The iron(III) atom can then be reduced and lead to the formation of hydroperoxyl radicals. The free radicals generated by these reactions engage in secondary reactions that can be very deleterious to their environment.