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Free Radicals and Antioxidants
Published in Chuong Pham-Huy, Bruno Pham Huy, Food and Lifestyle in Health and Disease, 2022
Chuong Pham-Huy, Bruno Pham Huy
Pro-oxidant refers to any endobiotic or xenobiotic that induces oxidative stress either by generation of harmful reactive oxygen species (ROS) or by inhibiting helpful antioxidant systems in the body (85–86). Pro-oxidants can damage cells and tissues. In general, the term ‘pro-oxidant’ is reserved for compounds that have antioxidant properties, but in certain conditions such as high dosage or prolonged use, they becomes harmful or toxic to the organism. For example, vitamin C is a strong antioxidant at low doses, and is used to fight or prevent diseases, but it becomes harmful to the body at high doses and can cause diseases. In this case, vitamin C becomes a pro-oxidant compound. Pro-oxidant is different from oxidant although these two compounds can both give oxidative stress and become toxic to the organism. Oxidant denotes a compound that produces an oxidation reaction and does not have antioxidant property in any dose or any physiological situation. For example, ozone O3 and hydrogen peroxide H2O2 are oxidant compounds, and not pro-oxidants because they do not have antioxidant property, in contrast to vitamin C. Therefore, the term ‘pro-oxidant’ is reserved for compounds that have an antioxidant property.
Delivery Strategies and Formulation Approaches of Anticancer Nutraceuticals
Published in Sheeba Varghese Gupta, Yashwant V. Pathak, Advances in Nutraceutical Applications in Cancer, 2019
Epigallocatechin-3-gallate (EGCG) is a type of catechin found in green tea that exhibits a variety of activities such as anti-inflammatory, antidiabetes, antiobesity, and antitumor. The antitumor effects of EGCG including carcinogen activity, tumorigenesis, proliferation, and angiogenesis, and induced cell death were reviewed [57]. These effects are associated with the modulation of reactive oxygen species [ROS] production, which is mainly responsible for its anticancer effects despite its dual function of antioxidant and pro-oxidant potential. The EGCG-mediated inhibition of the nuclear factor (κB) signaling is also associated with the inhibition of migration, angiogenesis, and cell viability. Further, activation of mitogen-activated protein kinases activity upregulates the anticancer effect of EGCG on migration, invasion, and apoptosis. Additionally, EGCG causes the upregulation of apoptosis by inducing epigenetic modification through inhibition of DNA methyltransferase activity and regulation of acetylation on histone. Although EGCG promotes strong anticancer effects by multiple mechanisms, further studies are needed to define the use of EGCG in clinical treatment [58].
Impact of Dietary Polyphenols on Arterial Stiffness
Published in Catherina Caballero-George, Natural Products and Cardiovascular Health, 2018
Tess De Bruyne, Lynn Roth, Harry Robberecht, Luc Pieters, Guido De Meyer, Nina Hermans
Oxidative stress is defined as an imbalance between reactive oxygen species (ROS) formation and elimination in favor of pro-oxidant processes. During vascular oxidative stress, it has been demonstrated that, in the vascular wall, many enzymatic systems produce reactive oxygen species (ROS), including nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, mitochondrial enzymes, dysfunctional endothelial nitric oxide synthase (eNOS) and xanthine oxidase (XO). Vascular cells also have several antioxidant systems to counteract ROS generation: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), paraoxonase (PONs), thioredoxin (TRX) peroxidase and heme oxygenase (Hmox) (Santilli et al., 2015).
Pre-imaginal exposure to mancozeb induces morphological and behavioral deficits and oxidative damage in Drosophila melanogaster
Published in Drug and Chemical Toxicology, 2023
Cynthia Camila Ziech, Nathane Rosa Rodrigues, Giulianna Echeverria Macedo, Karen Kich Gomes, Illana Kemmerich Martins, Jeferson Luis Franco, Thaís Posser
The toxicological effects of MZ are attributed to the presence of metals manganese and zinc in its formulation, which could lead to metal accumulation in tissues like the brain (Costa-Silva et al. 2018). Together with the presence of metal, the main MZ degradation byproduct ethylene thiourea (ETU), which demonstrated genotoxic potential (Deardfield 1994) has been implied in MZ toxicity. The mechanisms of action underlying MZ toxicity are not entirely known; however, oxidative stress (OS) is recognized as a primary factor in MZ. Oxidative stress (OS) results from an imbalance between the levels of reactive oxygen species (ROS) and antioxidant defense acting in the neutralization of those species (Davies 2000). In addition, a cellular pro-oxidant environment may damage biomolecules like proteins, lipids, and nucleic acids and has been implied in the etiology of pathologies like tumors and neurodegenerative disorders (Valko et al. 2006, Uttara et al. 2009, Phom et al. 2014). In this context, inhibition of mitochondrial complexes, NADPH oxidase, and xanthine oxidase induction and modulation in the activity of the antioxidant enzymes were reported to MZ (Zhang et al. 2003, Hogarth 2012, Todt et al. 2016, Costa-Silva et al. 2018).
Oxidative versus reductive stress: a delicate balance for sperm integrity
Published in Systems Biology in Reproductive Medicine, 2023
Niloofar Sadeghi, Guylain Boissonneault, Marziyeh Tavalaee, Mohammad Hossein Nasr-Esfahani
Cellular redox is defined as a balance between pro‐oxidants and antioxidants. As previously reported in the literature, cellular pro-oxidants comprise ROS, generated in the form of superoxide anion (O2•‐), hydrogen peroxide (H2O2) from the electron transport chain (ETC), or mitochondrial enzymes such as NADPH-dependent oxidase 4 (NOX4) and α-ketoglutarate dehydrogenase (α-KGDH) (Figure 1) (Handy and Loscalzo 2012; Xiao and Loscalzo 2020). That is why cells contain a broad range of antioxidants, including enzymatic antioxidants (superoxide dismutases (SOD1‐3), catalase, glutathione peroxidases (GPx1‐8), thioredoxins (Trx1‐2), and peroxiredoxins (Prx1‐6) and non-enzymatic antioxidants (GSH, α‐tocopherol, Folic acid, Bilirubin, uric acid, Carotenoids, ascorbate, etc.) to neutralize cellular oxidants (O'Flaherty 2014; Cheng and Ko 2019; Xiao and Loscalzo 2020; Rashki Ghaleno et al. 2021). However, cellular functions such as cell signaling, proliferation, and differentiation require a steady‐state level of cellular pro-oxidant under physiological conditions. Hence, any impairment in pro‐oxidants and antioxidants status leads to either oxidative or reductive stress known as redox stress (Pérez-Torres et al. 2017).
Adherence to Oxidative Balance Scores is Associated with a Reduced Risk of Breast Cancer; A Case-Control Study
Published in Nutrition and Cancer, 2022
Mohammad Hassan Sohouli, Mansoureh Baniasadi, Ángela Hernández-Ruiz, Ebru Melekoglu, Mona Zendehdel, María José Soto-Méndez, Atieh Akbari, Mitra Zarrati
In the present study, we used the method described by Goodman et al. to calculate the OBS of each participant. According to this method, a total of 13 dietary and nondietary pro- and antioxidant components, based on a priori knowledge about their association to oxidative stress, were selected. The components were divided into four groups: (1) dietary antioxidants (selenium, fiber, β-carotene, vitamin D, vitamin C, vitamin E, and folate); (2) dietary prooxidants (iron and saturated (SFA) and polyunsaturated (PUFA) fatty acids); (3) nondietary antioxidant (physical activity); and (4) nondietary prooxidants (smoking and obesity). Dietary factors were ranked into quintiles. For dietary antioxidants and physical activity, the first to fifth quintiles were assigned scores of 1–5. An inverse scoring was used for dietary prooxidants. For obesity, we assigned 1: BMI ≥ 30 kg/m2 and WC ≥ 102 cm in males and ≥88 cm in females, 3: either BMI ≥ 30 kg/m2 or WC ≥ 102 cm in males or ≥88 cm in females, and 5: BMI < 30 kg/m2 and WC < 102 in males or <88 cm in females. For smoking, it was assigned 1: current smoking, 3: former smoking, and 5: never smoking. The score of four components was then summed to calculate the OBS for each participant. A higher score of OBS indicates more adherence to this score derived from diet and a lower score indicates less adherence to this score. The minimum and maximum scores possible are, respectively, 5 and 65.