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Antioxidants, Volume 11, Issue 1 (January 2022) – 176 articles

Cover Story (view full-size image): Investigation of cell metabolism is hampered by the imprint of classical non-physiological media on various pathways. We evaluated changes in metabolism of four mammalian cell lines cultivated in human plasma-resembling Plasmax medium. This promoted the assembly of mitochondria into vast networks leading to enhanced respiration and increased sensitivity to respiration complex inhibitors. Plasmax also reduced lysosomal mass in cells. Cells maintained in Plasmax supported lower levels of replication of RNA viruses, including hepatitis C and influenza A viruses as well as SARS-CoV-2. Interestingly, levels of oxidative stress markers remained unchanged, pointing to a higher ability of the viruses in Plasmax to trigger ROS production. Altogether, these data clearly show that the physiological Plasmax medium should be used in metabolomics and redox biology studies. View this paper.
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Review
Seaweed-Derived Proteins and Peptides: Promising Marine Bioactives
Antioxidants 2022, 11(1), 176; https://doi.org/10.3390/antiox11010176 - 17 Jan 2022
Viewed by 1026
Abstract
Seaweeds are a typical food of East-Asian cuisine, to which are alleged several beneficial health effects have been attributed. Their availability and their nutritional and chemical composition have favored the increase in its consumption worldwide, as well as a focus of research due [...] Read more.
Seaweeds are a typical food of East-Asian cuisine, to which are alleged several beneficial health effects have been attributed. Their availability and their nutritional and chemical composition have favored the increase in its consumption worldwide, as well as a focus of research due to their bioactive properties. In this regard, seaweed proteins are nutritionally valuable and comprise several specific enzymes, glycoproteins, cell wall-attached proteins, red algae phycobiliproteins, lectins, peptides, or mycosporine-like amino acids. This great extent of molecules has been reported to exert significant antioxidant, antimicrobial, anti-inflammatory, antihypertensive, antidiabetic, or antitumoral properties. Hence, knowledge on algae proteins and derived compounds have gained special interest for the potential nutraceutical, cosmetic or pharmaceutical industries based on these bioactivities. Although several molecular mechanisms of action on how these proteins and peptides exert biological activities have been described, many gaps in knowledge still need to be filled. Updating the current knowledge related to seaweed proteins and peptides is of interest to further asses their potential health benefits. This review addresses the characteristics of seaweed protein and protein-derived molecules, their natural occurrence, their studied bioactive properties, and their described potential mechanisms of action. Full article
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Article
Acremonium terricola Culture’s Dose–Response Effects on Lactational Performance, Antioxidant Capacity, and Ruminal Characteristics in Holstein Dairy Cows
Antioxidants 2022, 11(1), 175; https://doi.org/10.3390/antiox11010175 - 17 Jan 2022
Viewed by 532
Abstract
Acremonium terricola culture (ATC) has similar bioactive constituents to Cordyceps and is known for its nutrient and pharmacological value, indicating the potential of ATC as a new feed additive in dairy cow feeding. The primary aim of this experiment was to investigate the [...] Read more.
Acremonium terricola culture (ATC) has similar bioactive constituents to Cordyceps and is known for its nutrient and pharmacological value, indicating the potential of ATC as a new feed additive in dairy cow feeding. The primary aim of this experiment was to investigate the effects of increasing amounts of ATC in diets on milk performance, antioxidant capacity, and rumen fermentation, and the secondary aim was to evaluate the potential effects of high doses of ATC. A total of 60 multiparous Holstein cows (110 ± 21 days in milk; 2.53 ± 0.82 parity) were assigned into 15 blocks and randomly assigned to one of four groups: 0, 30, 60, or 300 g/d of ATC per cow for 97 days. Data were analyzed using repeated measures in the Mixed procedure. Dry-matter intake was not changed (p > 0.05), while energy-corrected milk and fat-corrected milk yields increased linearly and quadratically, and somatic cell count in milk decreased linearly and quadratically (p < 0.05). The lactation efficiency and the yields of milk fat and protein increased linearly (p < 0.05). On day 90, serum catalase level, total oxidative capacity, glutathione peroxidase, immunoglobulin A, and immunoglobulin M concentrations were significantly higher in the 60 and 300 g/d groups than in the 0 g/d group (p < 0.05). ATC addition showed linear effects on total volatile fatty acid (VFA), acetate, branched VFA concentrations, and rumen pH (p < 0.05). Supplementing 60 and 300 g/d ATC significantly affected the bacterial composition (p < 0.05). The relative abundance of Christensenellaceae_R–7_group and Lachnospiraceae_NK3A20_group were significantly increased by 60 g/d supplementation, and the relative abundance of Erysipelotrichaceae_UCG_002, Acetitomaculum, Olsenella, and Syntrophococcus were significantly increased by 300 g/d supplementation (p < 0.05). ATC was effective in enhancing rumen fermentation and reducing somatic cell count in milk, thereby improving milk yield. The optimized dose of ATC was 60 g/d for lactating cows, and there were no risks associated with high doses of ATC. Full article
(This article belongs to the Special Issue Antioxidants in Animal Feed)
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Article
Near-Infrared Light-Triggered Generation of Reactive Oxygen Species and Induction of Local Hyperthermia from Indocyanine Green Encapsulated Mesoporous Silica-Coated Graphene Oxide for Colorectal Cancer Therapy
Antioxidants 2022, 11(1), 174; https://doi.org/10.3390/antiox11010174 - 17 Jan 2022
Viewed by 544
Abstract
Near-infrared (NIR) light-mediated photothermal therapy (PTT) and photodynamic therapy (PDT) have widely been used for cancer treatment applications. However, a number of limitations (e.g., low NIR absorption capacity of photothermal agents, insufficient loading efficiency of photosensitive molecules) have hindered the widespread use of [...] Read more.
Near-infrared (NIR) light-mediated photothermal therapy (PTT) and photodynamic therapy (PDT) have widely been used for cancer treatment applications. However, a number of limitations (e.g., low NIR absorption capacity of photothermal agents, insufficient loading efficiency of photosensitive molecules) have hindered the widespread use of NIR-mediated cancer therapy. Therefore, we developed a mesoporous silica-coated reduced graphene oxide (rGO) nanocomposite that could provide a high encapsulation rate of indocyanine green (ICG) and enhance PTT/PDT efficiency in vitro and in vivo. The ICG-encapsulated nanocomposite not only enhances the photothermal effect but also generates a large number of tumor toxic reactive oxygen species (ROS). By conjugation of polyethylene glycol (PEG) with folic acid (FA) as a tumor targeting moiety, we confirmed that ICG-encapsulated mesoporous silica (MS)-coated rGO nanocomposite ([email protected]) exhibited high colloidal stability and intracellular uptake in folate receptor-expressing CT-26 colorectal cancer cells. Upon NIR laser irradiation, this [email protected] nanocomposite induced the apoptosis of only CT-26 cells via enhanced PTT and PDT effects without any damage to normal cells. Furthermore, the [email protected] nanocomposite revealed satisfactory tumor targeting and biocompatibility in CT-26 tumor-bearing mice, thereby enhancing the therapeutic effects of PTT and PDT in vivo. Therefore, this tumor-targeted [email protected] nanocomposite shows a great potential for phototherapy applications. Full article
(This article belongs to the Section ROS, RNS and RSS)
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Article
Combined Treatment with Herbal Medicine and Drug Ameliorates Inflammation and Metabolic Abnormalities in the Liver of an Amyotrophic Lateral Sclerosis Mouse Model
Antioxidants 2022, 11(1), 173; https://doi.org/10.3390/antiox11010173 - 17 Jan 2022
Cited by 1 | Viewed by 513
Abstract
To date, no effective drugs exist for amyotrophic lateral sclerosis (ALS), although riluzole (RZ) and edaravone have been approved for treatment. We previously reported that Bojungikgi-tang (BJIGT) improved motor activity through anti-inflammatory effects in the muscle and spinal cord of hSOD1G93A mice. [...] Read more.
To date, no effective drugs exist for amyotrophic lateral sclerosis (ALS), although riluzole (RZ) and edaravone have been approved for treatment. We previously reported that Bojungikgi-tang (BJIGT) improved motor activity through anti-inflammatory effects in the muscle and spinal cord of hSOD1G93A mice. Therefore, whether combined treatment with BJIGT and RZ synergistically affects liver function in hSOD1G93A mice was investigated. Two-month-old male hSOD1G93A mice were treated with BJIGT (1 mg/g) and RZ (8 μg/g) administered orally for 5 weeks. Drug metabolism and liver function tests of serum and liver homogenates were conducted. mRNA expression levels of cytochrome P450 (CYP) isozymes, inflammatory cytokines, metabolic factors, and mitochondrial oxidative phosphorylation (OXPHOS) subunits were examined using qPCR and Western blotting. Combined administration of BJIGT and RZ did not alter mRNA expression levels of drug-metabolism-related isozymes (CYP1A2 and CYP3A4) but significantly decreased the activity of liver-function-related enzymes (AST, ALT, ALP, and LDH). Increased expression of inflammatory cytokines (IL-1β, TNF-α, and IL-6) and of intracellular stress-related proteins (Bax, AMPKα, JNK, and p38) was reduced by the combined treatment in hSOD1G93A mice compared to that in control mice. Combined administration reduced the mRNA expression of metabolism-related factors and the expression of OXPHOS subunits. Elevated ATP levels and mitochondrial-fusion-associated protein were decreased after co-administration. Co-administration of BJIGT and RZ did not cause liver damage or toxicity but rather restored liver function in hSOD1G93A mice. This suggests that this combination can be considered a candidate therapeutic agent for ALS. Full article
(This article belongs to the Special Issue Oxidative Stress and Mitochondrial Dysfunction in Disease)
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Review
Arterial Hypertension—Oxidative Stress and Inflammation
Antioxidants 2022, 11(1), 172; https://doi.org/10.3390/antiox11010172 - 17 Jan 2022
Cited by 2 | Viewed by 676
Abstract
Arterial hypertension (AH) is a major cause of cardiovascular diseases (CVD), leading to dysfunction of many organs, including the heart, blood vessels and kidneys. AH is a multifactorial disease. It has been suggested that the development of each factor is influenced by oxidative [...] Read more.
Arterial hypertension (AH) is a major cause of cardiovascular diseases (CVD), leading to dysfunction of many organs, including the heart, blood vessels and kidneys. AH is a multifactorial disease. It has been suggested that the development of each factor is influenced by oxidative stress, which is characterized by a disturbed oxidant-antioxidant balance. Excessive production of reactive oxygen species (ROS) and an impaired antioxidant system promote the development of endothelial dysfunction (ED), inflammation and increased vascular contractility, resulting in remodeling of cardiovascular (CV) tissue. The hope for restoring the proper functioning of the vessels is placed on antioxidants, and pharmacological strategies are still being sought to reverse the harmful effects of free radicals. In our review, we focused on the correlation of AH with oxidative stress and inflammation, which are influenced by many factors, such as diet, supplementation and pharmacotherapy. Studies show that the addition of a single dietary component may have a beneficial effect on blood pressure (BP) values; however, the relationship between the antioxidant/anti-inflammatory properties of individual dietary components and the hypotensive effect is not clear. Moreover, AH pharmacotherapy alleviates the increased oxidative stress, which may help prevent organ damage. Full article
(This article belongs to the Special Issue Oxidative Stress and Inflammation in Cardiovascular Diseases II)
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Article
Inhibitory Effects of 6,8-Diprenylorobol on Endometriosis Progression in Humans by Disrupting Calcium Homeostasis and Mitochondrial Function
Antioxidants 2022, 11(1), 171; https://doi.org/10.3390/antiox11010171 - 17 Jan 2022
Viewed by 479
Abstract
6,8-Diprenylorobol is a flavonoid compound extracted from Cudrania tricuspidata. It has various biological functions, such as inhibiting melanin synthesis and inducting cell death in cancerous cells. In addition, Cudrania tricuspidata is known to be effective in female diseases, and previous studies have [...] Read more.
6,8-Diprenylorobol is a flavonoid compound extracted from Cudrania tricuspidata. It has various biological functions, such as inhibiting melanin synthesis and inducting cell death in cancerous cells. In addition, Cudrania tricuspidata is known to be effective in female diseases, and previous studies have shown anticancer effects in cervical cancer, a female reproductive disease. Outside of that, Cudrania tricuspidata has various physiological effects. However, the effect of 6,8-diprenylorobol is not well known in other benign and chronic diseases, even in endometriosis, which commonly arises in the female reproductive tract. In the present study, we determined the inhibitory effects of 6,8-diprenylorobol on the growth of endometriosis VK2/E6E7 and End1/E6E7 cells. Results indicated that 6,8-diprenylorobol suppressed cellular proliferation and increased the disruption of the cell cycle, mitochondrial membrane potential (MMP), generation of reactive oxygen species, and Ca2+ homeostasis in both endometriosis cells. However, the proliferation of normal stromal cells isolated from endometrial tissue was not altered by 6,8-diprenylorobol. The change in Ca2+ levels was estimated in fluo-4- or rhod-2-stained VK2/E6E7 and End1/E6E7 cells after the treatment of the intracellular calcium regulators 2-aminoethoxydiphenyl borate (2-APB) and ruthenium red (RUR) with 6,8-diprenylorobol. A combination of 6,8-diprenylorobol with each regulator decreased the calcium accumulation in endometriosis cells. Furthermore, Western blot analysis indicated that 6,8-diprenylorobol inactivated AKT pathways, whereas it activated P38 MAPK pathways. In addition, 6,8-diprenylorobol decreased mitochondrial respiration, leading to the reduction in ATP production in VK2/E6E7 and End1/E6E7 cells. Collectively, our results suggested that 6,8-diprenylorobol might be a potential therapeutic agent or adjuvant therapy for the management of endometriosis. Full article
(This article belongs to the Special Issue Mitochondria Biology in Reproductive Function)
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Review
Neuroprotection and Disease Modification by Astrocytes and Microglia in Parkinson Disease
Antioxidants 2022, 11(1), 170; https://doi.org/10.3390/antiox11010170 - 17 Jan 2022
Viewed by 789
Abstract
Oxidative stress and neuroinflammation are common bases for disease onset and progression in many neurodegenerative diseases. In Parkinson disease, which is characterized by the degeneration of dopaminergic neurons resulting in dopamine depletion, the pathogenesis differs between hereditary and solitary disease forms and is [...] Read more.
Oxidative stress and neuroinflammation are common bases for disease onset and progression in many neurodegenerative diseases. In Parkinson disease, which is characterized by the degeneration of dopaminergic neurons resulting in dopamine depletion, the pathogenesis differs between hereditary and solitary disease forms and is often unclear. In addition to the pathogenicity of alpha-synuclein as a pathological disease marker, the involvement of dopamine itself and its interactions with glial cells (astrocyte or microglia) have attracted attention. Pacemaking activity, which is a hallmark of dopaminergic neurons, is essential for the homeostatic maintenance of adequate dopamine concentrations in the synaptic cleft, but it imposes a burden on mitochondrial oxidative glucose metabolism, leading to reactive oxygen species production. Astrocytes provide endogenous neuroprotection to the brain by producing and releasing antioxidants in response to oxidative stress. Additionally, the protective function of astrocytes can be modified by microglia. Some types of microglia themselves are thought to exacerbate Parkinson disease by releasing pro-inflammatory factors (M1 microglia). Although these inflammatory microglia may further trigger the inflammatory conversion of astrocytes, microglia may induce astrocytic neuroprotective effects (A2 astrocytes) simultaneously. Interestingly, both astrocytes and microglia express dopamine receptors, which are upregulated in the presence of neuroinflammation. The anti-inflammatory effects of dopamine receptor stimulation are also attracting attention because the functions of astrocytes and microglia are greatly affected by both dopamine depletion and therapeutic dopamine replacement in Parkinson disease. In this review article, we will focus on the antioxidative and anti-inflammatory effects of astrocytes and their synergism with microglia and dopamine. Full article
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Review
Hydropersulfides (RSSH) and Nitric Oxide (NO) Signaling: Possible Effects on S-Nitrosothiols (RS-NO)
Antioxidants 2022, 11(1), 169; https://doi.org/10.3390/antiox11010169 - 16 Jan 2022
Viewed by 435
Abstract
S-Nitrosothiol (RS-NO) formation in proteins and peptides have been implicated as factors in the etiology of many diseases and as possible regulators of thiol protein function. They have also been proposed as possible storage forms of nitric oxide (NO). However, despite their proposed [...] Read more.
S-Nitrosothiol (RS-NO) formation in proteins and peptides have been implicated as factors in the etiology of many diseases and as possible regulators of thiol protein function. They have also been proposed as possible storage forms of nitric oxide (NO). However, despite their proposed functions/roles, there appears to be little consensus regarding the physiological mechanisms of RS-NO formation and degradation. Hydropersulfides (RSSH) have recently been discovered as endogenously generated species with unique reactivity. One important reaction of RSSH is with RS-NO, which leads to the degradation of RS-NO as well as the release of NO. Thus, it can be speculated that RSSH can be a factor in the regulation of steady-state RS-NO levels, and therefore may be important in RS-NO (patho)physiology. Moreover, RSSH-mediated NO release from RS-NO may be a possible mechanism allowing RS-NO to serve as a storage form of NO. Full article
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Article
Protection against Neurological Symptoms by Consuming Corn Silk Water Extract in Artery-Occluded Gerbils with Reducing Oxidative Stress, Inflammation, and Post-Stroke Hyperglycemia through the Gut-Brain Axis
Antioxidants 2022, 11(1), 168; https://doi.org/10.3390/antiox11010168 - 16 Jan 2022
Viewed by 651
Abstract
Corn silk (Stigma maydis), rich in flavonoids, is traditionally used to treat edema, depression, and hyperglycemia and may alleviate ischemic stroke symptoms in Chinese medicine. This study examined whether corn silk water extract (CSW) could alleviate ischemic stroke symptoms and post-stroke [...] Read more.
Corn silk (Stigma maydis), rich in flavonoids, is traditionally used to treat edema, depression, and hyperglycemia and may alleviate ischemic stroke symptoms in Chinese medicine. This study examined whether corn silk water extract (CSW) could alleviate ischemic stroke symptoms and post-stroke hyperglycemia in Mongolian gerbils with transient cerebral ischemia and reperfusion (I/R). After being given 0.05% (I/R-LCSW) and 0.2% (I/R-HCSW), 0.02% aspirin (I/R-aspirin), and cellulose (I/R-control) in their 40 energy% fat diets for three weeks, the gerbils underwent an artery occlusion for eight minutes and reperfusion. They took the assigned diet for an additional three weeks. Sham-operated gerbils without artery occlusion had the same diet as Sham-control. CSW intake reduced neuronal cell death in gerbils with I/R and dose-dependently improved the neurological symptoms, including drooped eyes, crouched posture, flexor reflex, and walking patterns. CSW intake also alleviated the short-term memory and spontaneous alteration and grip strength compared to the I/R-control group. The protection against ischemic stroke symptoms was associated with the reduced tumor necrosis factor-α, interleukin-1β, superoxide, and lipid peroxide levels, promoting superoxide dismutase activity in the hippocampus in the CSW groups, compared to the I/R-control. The blood flow measured by Doppler was improved with CSW compared to the I/R-control. Furthermore, CSW intake prevented the post-stroke hyperglycemia related to decreasing pancreatic β-cell mass as much as the Sham-control, and it was related to protection against β-cell apoptosis, restoring the β-cell mass similar to the Sham-control. CSW intake elevated the relative abundance of Lactobacillus, Bifidobacterium, Allobaculum, and Akkermansia compared to the I/R-control. Picrust2 analysis showed that CSW increased the propionate and butyrate metabolism and the starch and glucose metabolism but reduced lipopolysaccharide biosynthesis compared to the I/R-control. In conclusion, CSW intake protects against neuronal cell death and post-hyperglycemia by reducing oxidative stress and inflammation and increasing blood flow and the β-cell mass. The alleviation was associated with promoting the gut-brain axis by changing the gut microbiome community. Full article
(This article belongs to the Special Issue Dietary Antioxidants against Neurodegenerative Diseases)
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Review
Antioxidant Paradox in Male Infertility: ‘A Blind Eye’ on Inflammation
Antioxidants 2022, 11(1), 167; https://doi.org/10.3390/antiox11010167 - 16 Jan 2022
Cited by 2 | Viewed by 643
Abstract
The pathophysiology of male infertility involves various interlinked endogenous pathways. About 50% of the cases of infertility in men are idiopathic, and oxidative stress (OS) reportedly serves as a central mechanism in impairing male fertility parameters. The endogenous antioxidant system operates to conserve [...] Read more.
The pathophysiology of male infertility involves various interlinked endogenous pathways. About 50% of the cases of infertility in men are idiopathic, and oxidative stress (OS) reportedly serves as a central mechanism in impairing male fertility parameters. The endogenous antioxidant system operates to conserve the seminal redox homeostasis required for normal male reproduction. OS strikes when a generation of seminal reactive oxygen species (ROS) overwhelms endogenous antioxidant capacity. Thus, antioxidant treatment finds remarkable relevance in the case of idiopathic male infertility or subfertility. However, due to lack of proper detection of OS in male infertility, use of antioxidant(s) in some cases may be arbitrary or lead to overuse and induction of ‘reductive stress’. Moreover, inflammation is closely linked to OS and may establish a vicious loop that is capable of disruption to male reproductive tissues. The result is exaggeration of cellular damage and disruption of male reproductive tissues. Therefore, limitations of antioxidant therapy in treating male infertility are the failure in the selection of specific treatments targeting inflammation and OS simultaneously, two of the core mechanisms of male infertility. The present review aims to elucidate the antioxidant paradox in male infertility treatment, from the viewpoints of both induction of reductive stress as well as overlooking the inflammatory consequences. Full article
(This article belongs to the Special Issue Paradoxical Oxidative Therapies in Chronic Oxidative Stress Diseases)
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Article
Multitarget Antioxidant NO-Donor Organic Nitrates: A Novel Approach to Overcome Nitrates Tolerance, an Ex Vivo Study
Antioxidants 2022, 11(1), 166; https://doi.org/10.3390/antiox11010166 - 16 Jan 2022
Viewed by 399
Abstract
Chronic use of glyceryl trinitrate (GTN) is limited by serious side effects, such as tolerance and endothelial dysfunction of coronary and resistance arteries. Although GTN is used as a drug since more than 130 years, the mechanisms of the vasodilatory effects and of [...] Read more.
Chronic use of glyceryl trinitrate (GTN) is limited by serious side effects, such as tolerance and endothelial dysfunction of coronary and resistance arteries. Although GTN is used as a drug since more than 130 years, the mechanisms of the vasodilatory effects and of tolerance development to organic nitrates are still incompletely elucidated. New synthesized organic nitrates with and without antioxidant properties were characterized for their ex vivo tolerance profile, in order to investigate the oxidative stress hypothesis of nitrate tolerance. The organic nitrates studied showed different vasodilation and tolerance profiles, probably due to the ability or inability of the compounds to interact with the aldehyde dehydrogenase-2 enzyme (ALDH-2) involved in bioactivation. Furthermore, nitrooxy derivatives endowed with antioxidant properties did not determine the onset of tolerance, even if bioactivated by ALDH-2. The results of this study could be further evidence of the involvement of ALDH-2 in the development of nitrate tolerance. Moreover, the behavior of organic nitrates with antioxidant properties supports the hypothesis of the involvement of ROS in inactivating ALDH-2. Full article
(This article belongs to the Special Issue NO-Donors with Antioxidant Activities)
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Review
Therapeutic Strategies Targeting Mitochondrial Calcium Signaling: A New Hope for Neurological Diseases?
Antioxidants 2022, 11(1), 165; https://doi.org/10.3390/antiox11010165 - 15 Jan 2022
Cited by 1 | Viewed by 759
Abstract
Calcium (Ca2+) is a versatile secondary messenger involved in the regulation of a plethora of different signaling pathways for cell maintenance. Specifically, intracellular Ca2+ homeostasis is mainly regulated by the endoplasmic reticulum and the mitochondria, whose Ca2+ exchange is [...] Read more.
Calcium (Ca2+) is a versatile secondary messenger involved in the regulation of a plethora of different signaling pathways for cell maintenance. Specifically, intracellular Ca2+ homeostasis is mainly regulated by the endoplasmic reticulum and the mitochondria, whose Ca2+ exchange is mediated by appositions, termed endoplasmic reticulum–mitochondria-associated membranes (MAMs), formed by proteins resident in both compartments. These tethers are essential to manage the mitochondrial Ca2+ influx that regulates the mitochondrial function of bioenergetics, mitochondrial dynamics, cell death, and oxidative stress. However, alterations of these pathways lead to the development of multiple human diseases, including neurological disorders, such as amyotrophic lateral sclerosis, Friedreich’s ataxia, and Charcot–Marie–Tooth. A common hallmark in these disorders is mitochondrial dysfunction, associated with abnormal mitochondrial Ca2+ handling that contributes to neurodegeneration. In this work, we highlight the importance of Ca2+ signaling in mitochondria and how the mechanism of communication in MAMs is pivotal for mitochondrial maintenance and cell homeostasis. Lately, we outstand potential targets located in MAMs by addressing different therapeutic strategies focused on restoring mitochondrial Ca2+ uptake as an emergent approach for neurological diseases. Full article
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Article
The Trypanosoma brucei-Derived Ketoacids, Indole Pyruvate and Hydroxyphenylpyruvate, Induce HO-1 Expression and Suppress Inflammatory Responses in Human Dendritic Cells
Antioxidants 2022, 11(1), 164; https://doi.org/10.3390/antiox11010164 - 15 Jan 2022
Cited by 1 | Viewed by 553
Abstract
The extracellular parasite and causative agent of African sleeping sickness Trypanosoma brucei (T. brucei) has evolved a number of strategies to avoid immune detection in the host. One recently described mechanism involves the conversion of host-derived amino acids to aromatic ketoacids, [...] Read more.
The extracellular parasite and causative agent of African sleeping sickness Trypanosoma brucei (T. brucei) has evolved a number of strategies to avoid immune detection in the host. One recently described mechanism involves the conversion of host-derived amino acids to aromatic ketoacids, which are detected at relatively high concentrations in the bloodstream of infected individuals. These ketoacids have been shown to directly suppress inflammatory responses in murine immune cells, as well as acting as potent inducers of the stress response enzyme, heme oxygenase 1 (HO-1), which has proven anti-inflammatory properties. The aim of this study was to investigate the immunomodulatory properties of the T. brucei-derived ketoacids in primary human immune cells and further examine their potential as a therapy for inflammatory diseases. We report that the T. brucei-derived ketoacids, indole pyruvate (IP) and hydroxyphenylpyruvate (HPP), induce HO-1 expression through Nrf2 activation in human dendritic cells (DC). They also limit DC maturation and suppress the production of pro-inflammatory cytokines, which, in turn, leads to a reduced capacity to differentiate adaptive CD4+ T cells. Furthermore, the ketoacids are capable of modulating DC cellular metabolism and suppressing the inflammatory profile of cells isolated from patients with inflammatory bowel disease. This study therefore not only provides further evidence of the immune-evasion mechanisms employed by T. brucei, but also supports further exploration of this new class of HO-1 inducers as potential therapeutics for the treatment of inflammatory conditions. Full article
(This article belongs to the Special Issue Heme Oxygenase (HO)-1 as an Immunoregulator in Health and Disease)
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Review
Peroxide-Mediated Oxygenation of Organic Compounds by Fungal Peroxygenases
Antioxidants 2022, 11(1), 163; https://doi.org/10.3390/antiox11010163 - 14 Jan 2022
Cited by 4 | Viewed by 736
Abstract
Unspecific peroxygenases (UPOs), whose sequences can be found in the genomes of thousands of filamentous fungi, many yeasts and certain fungus-like protists, are fascinating biocatalysts that transfer peroxide-borne oxygen (from H2O2 or R-OOH) with high efficiency to a wide range [...] Read more.
Unspecific peroxygenases (UPOs), whose sequences can be found in the genomes of thousands of filamentous fungi, many yeasts and certain fungus-like protists, are fascinating biocatalysts that transfer peroxide-borne oxygen (from H2O2 or R-OOH) with high efficiency to a wide range of organic substrates, including less or unactivated carbons and heteroatoms. A twice-proline-flanked cysteine (PCP motif) typically ligates the heme that forms the heart of the active site of UPOs and enables various types of relevant oxygenation reactions (hydroxylation, epoxidation, subsequent dealkylations, deacylation, or aromatization) together with less specific one-electron oxidations (e.g., phenoxy radical formation). In consequence, the substrate portfolio of a UPO enzyme always combines prototypical monooxygenase and peroxidase activities. Here, we briefly review nearly 20 years of peroxygenase research, considering basic mechanistic, molecular, phylogenetic, and biotechnological aspects. Full article
(This article belongs to the Special Issue Dream Peroxygenases)
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Article
Potential Implications of Rimonabant on Age-Related Oxidative Stress and Inflammation
Antioxidants 2022, 11(1), 162; https://doi.org/10.3390/antiox11010162 - 14 Jan 2022
Cited by 1 | Viewed by 505
Abstract
Over the last decades, growing interest has turned to preventive and therapeutic approaches for achieving successful aging. Oxidative stress and inflammation are fundamental features of cardiovascular diseases; therefore, potential targets of them can improve cardiac outcomes. Our study aimed to examine the involvement [...] Read more.
Over the last decades, growing interest has turned to preventive and therapeutic approaches for achieving successful aging. Oxidative stress and inflammation are fundamental features of cardiovascular diseases; therefore, potential targets of them can improve cardiac outcomes. Our study aimed to examine the involvement of the endocannabinoid system, especially the CB1 receptor blockade, on inflammatory and oxidant/antioxidant processes. Twenty-month-old female and male Wistar rats were divided into rimonabant-treated and aging control (untreated) groups. Rimonabant, a selective CB1 receptor antagonist, was administered at the dose of 1 mg/kg/day intraperitoneally for 2 weeks. Cardiac amounts of ROS, the antioxidant glutathione and superoxide dismutase (SOD), and the activity and concentration of the heme oxygenase (HO) enzyme were detected. Among inflammatory parameters, nuclear factor-kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α), and myeloperoxidase (MPO) enzyme activity were measured. Two weeks of low dose rimonabant treatment significantly reduced the cardiac ROS via boosting of the antioxidant defense mechanisms as regards the HO system, and the SOD and glutathione content. Consistently, the age-related inflammatory response was alleviated. Rimonabant-treated animals showed significantly decreased NF-κB, TNF-α, and MPO levels. Our findings prove the beneficial involvement of CB1 receptor blocker rimonabant on inflammatory and oxidative damages to the aging heart. Full article
(This article belongs to the Special Issue Oxidative Stress in Chronic and Age-Related Diseases)
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Article
On the Role of the Carboxyl Group to the Protective Effect of o-dihydroxybenzoic Acids to Saccharomyces cerevisiae Cells upon Induced Oxidative Stress
Antioxidants 2022, 11(1), 161; https://doi.org/10.3390/antiox11010161 - 14 Jan 2022
Viewed by 453
Abstract
In the present work, the role of the carboxyl group of o-dihydroxybenzoic acids (pyrocatechuic, 2,3-diOH-BA and protocatechuic, 3,4-diOH-BA) on the protection against induced oxidative stress in Saccharomyces cerevisiae was examined. Catechol (3,4-diOH-B) was included for comparison. Cell survival, antioxidant enzyme activities, and [...] Read more.
In the present work, the role of the carboxyl group of o-dihydroxybenzoic acids (pyrocatechuic, 2,3-diOH-BA and protocatechuic, 3,4-diOH-BA) on the protection against induced oxidative stress in Saccharomyces cerevisiae was examined. Catechol (3,4-diOH-B) was included for comparison. Cell survival, antioxidant enzyme activities, and TBARS level were used to evaluate the efficiency upon the stress induced by H2O2 or cumene hydroperoxide. Theoretical calculation of atomic charge values, dipole moment, and a set of indices relevant to the redox properties of the compounds was also carried out in the liquid phase (water). Irrespective of the oxidant used, 2,3-diOH-BA required by far the lowest concentration (3–5 μM) to facilitate cell survival. The two acids did not activate catalase but reduced superoxide dismutase activity (3,4-diOH-BA>2,3-diOH-BA). TBARS assay showed an antioxidant effect only when H2O2 was used; equal activity for the two acids and inferior to that of 3,4-diOH B. Overall, theoretical and experimental findings suggest that the 2,3-diOH-BA high activity should be governed by metal chelation. In the case of 3,4-diOH BA, radical scavenging increases, and chelation capacity decreases. The lack of carboxyl moiety (3,4-diOH B) improves to radical scavenging, interaction with lipophilic free radicals, and antioxidant enzymes. The present study adds to our knowledge of the antioxidant mechanism of dietary phenols in biological systems. Full article
(This article belongs to the Section Natural and Synthetic Antioxidants)
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Article
Protective Effects of Transient Glucose Exposure in Adult C. elegans
Antioxidants 2022, 11(1), 160; https://doi.org/10.3390/antiox11010160 - 14 Jan 2022
Viewed by 456
Abstract
C. elegans are used to study molecular pathways, linking high glucose levels (HG) to diabetic complications. Persistent exposure of C. elegans to a HG environment induces the mitochondrial formation of reactive oxygen species (ROS) and advanced glycation endproducts (AGEs), leading to neuronal damage [...] Read more.
C. elegans are used to study molecular pathways, linking high glucose levels (HG) to diabetic complications. Persistent exposure of C. elegans to a HG environment induces the mitochondrial formation of reactive oxygen species (ROS) and advanced glycation endproducts (AGEs), leading to neuronal damage and decreased lifespan. Studies suggest that transient high glucose exposure (TGE) exerts different effects than persistent exposure. Thus, the effects of TGE on ROS, AGE-formation and life span were studied in C. elegans. Four-day TGE (400 mM) as compared to controls (0mM) showed a persistent increase of ROS (4-days 286 ± 40 RLUs vs. control 187 ± 23 RLUs) without increased formation of AGEs. TGE increased body motility (1-day 0.14 ± 0.02; 4-days 0.15 ± 0.01; 6-days 0.16 ± 0.02 vs. control 0.10 ± 0.02 in mm/s), and bending angle (1-day 17.7 ± 1.55; 3-days 18.7 ± 1.39; 6-days 20.3 ± 0.61 vs. control 15.3 ± 1.63 in degree/s) as signs of neuronal damage. Lifespan was increased by 27% (21 ± 2.4 days) after one-day TGE, 34% (22 ± 1.2 days) after four-days TGE, and 26% (21 ± 1.4 days) after six-days TGE vs. control (16 ± 1.3 days). These experiments suggest that TGE in C. elegans has positive effects on life span and neuronal function, associated with mildly increased ROS-formation. From the perspective of metabolic memory, hormetic effects outweighed the detrimental effects of a HG environment. Full article
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Article
Redox-Regulation of α-Globin in Vascular Physiology
Antioxidants 2022, 11(1), 159; https://doi.org/10.3390/antiox11010159 - 14 Jan 2022
Viewed by 366
Abstract
Interest in the structure, function, and evolutionary relations of circulating and intracellular globins dates back more than 60 years to the first determination of the three-dimensional structure of these proteins. Non-erythrocytic globins have been implicated in circulatory control through reactions that couple nitric [...] Read more.
Interest in the structure, function, and evolutionary relations of circulating and intracellular globins dates back more than 60 years to the first determination of the three-dimensional structure of these proteins. Non-erythrocytic globins have been implicated in circulatory control through reactions that couple nitric oxide (NO) signaling with cellular oxygen availability and redox status. Small artery endothelial cells (ECs) express free α-globin, which causes vasoconstriction by degrading NO. This reaction converts reduced (Fe2+) α-globin to the oxidized (Fe3+) form, which is unstable, cytotoxic, and unable to degrade NO. Therefore, (Fe3+) α-globin must be stabilized and recycled to (Fe2+) α-globin to reinitiate the catalytic cycle. The molecular chaperone α-hemoglobin-stabilizing protein (AHSP) binds (Fe3+) α-globin to inhibit its degradation and facilitate its reduction. The mechanisms that reduce (Fe3+) α-globin in ECs are unknown, although endothelial nitric oxide synthase (eNOS) and cytochrome b5 reductase (CyB5R3) with cytochrome b5 type A (CyB5a) can reduce (Fe3+) α-globin in solution. Here, we examine the expression and cellular localization of eNOS, CyB5a, and CyB5R3 in mouse arterial ECs and show that α-globin can be reduced by either of two independent redox systems, CyB5R3/CyB5a and eNOS. Together, our findings provide new insights into the regulation of blood vessel contractility. Full article
(This article belongs to the Special Issue NO Role in Evolution: Significance and Signaling)
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Article
PEG35 and Glutathione Improve Mitochondrial Function and Reduce Oxidative Stress in Cold Fatty Liver Graft Preservation
Antioxidants 2022, 11(1), 158; https://doi.org/10.3390/antiox11010158 - 14 Jan 2022
Cited by 1 | Viewed by 506
Abstract
The need to meet the demand for transplants entails the use of steatotic livers, more vulnerable to ischemia-reperfusion (IR) injury. Therefore, finding the optimal composition of static cold storage (SCS) preservation solutions is crucial. Given that ROS regulation is a therapeutic strategy for [...] Read more.
The need to meet the demand for transplants entails the use of steatotic livers, more vulnerable to ischemia-reperfusion (IR) injury. Therefore, finding the optimal composition of static cold storage (SCS) preservation solutions is crucial. Given that ROS regulation is a therapeutic strategy for liver IR injury, we have added increasing concentrations of PEG35 and glutathione (GSH) to the preservation solutions (IGL-1 and IGL-2) and evaluated the possible protection against energy depletion and oxidative stress. Fatty livers from obese Zücker rats were isolated and randomly distributed in the control (Sham) preserved (24 h at 4 °C) in IGL-0 (without PEG35 and 3 mmol/L GSH), IGL-1 (1 g/L PEG35, and 3 mmol/L GSH), and IGL-2 (5 g/L PEG35 and 9 mmol/L GSH). Energy metabolites (ATP and succinate) and the expression of mitochondrial oxidative phosphorylation complexes (OXPHOS) were determined. Mitochondrial carrier uncoupling protein 2 (UCP2), PTEN-induced kinase 1 (PINK1), nuclear factor-erythroid 2 related factor 2 (Nrf2), heme oxygenase-1 (HO-1), and the inflammasome (NLRP3) expressions were analyzed. As biomarkers of oxidative stress, protein oxidation (AOPP) and carbonylation (DNP derivatives), and lipid peroxidation (malondialdehyde (MDA)–thiobarbituric acid (TBA) adducts) were measured. In addition, the reduced and oxidized glutathione (GSH and GSSG) and enzymatic (Cu–Zn superoxide dismutase (SOD), CAT, GSH S-T, GSH-Px, and GSH-R) antioxidant capacities were determined. Our results showed that the cold preservation of fatty liver graft depleted ATP, accumulated succinate and increased oxidative stress. In contrast, the preservation with IGL-2 solution maintained ATP production, decreased succinate levels and increased OXPHOS complexes I and II, UCP2, and PINK-1 expression, therefore maintaining mitochondrial integrity. IGL-2 also protected against oxidative stress by increasing Nrf2 and HO-1 expression and GSH levels. Therefore, the presence of PEG35 in storage solutions may be a valuable option as an antioxidant agent for organ preservation in clinical transplantation. Full article
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Review
The Interconnected Mechanisms of Oxidative Stress and Neuroinflammation in Epilepsy
Antioxidants 2022, 11(1), 157; https://doi.org/10.3390/antiox11010157 - 14 Jan 2022
Cited by 1 | Viewed by 800
Abstract
One of the most important characteristics of the brain compared to other organs is its elevated metabolic demand. Consequently, neurons consume high quantities of oxygen, generating significant amounts of reactive oxygen species (ROS) as a by-product. These potentially toxic molecules cause oxidative stress [...] Read more.
One of the most important characteristics of the brain compared to other organs is its elevated metabolic demand. Consequently, neurons consume high quantities of oxygen, generating significant amounts of reactive oxygen species (ROS) as a by-product. These potentially toxic molecules cause oxidative stress (OS) and are associated with many disorders of the nervous system, where pathological processes such as aberrant protein oxidation can ultimately lead to cellular dysfunction and death. Epilepsy, characterized by a long-term predisposition to epileptic seizures, is one of the most common of the neurological disorders associated with OS. Evidence shows that increased neuronal excitability—the hallmark of epilepsy—is accompanied by neuroinflammation and an excessive production of ROS; together, these factors are likely key features of seizure initiation and propagation. This review discusses the role of OS in epilepsy, its connection to neuroinflammation and the impact on synaptic function. Considering that the pharmacological treatment options for epilepsy are limited by the heterogeneity of these disorders, we also introduce the latest advances in anti-epileptic drugs (AEDs) and how they interact with OS. We conclude that OS is intertwined with numerous physiological and molecular mechanisms in epilepsy, although a causal relationship is yet to be established. Full article
(This article belongs to the Special Issue Oxidative Stress in Neurons)
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Article
Age-Related Mitochondrial Impairment and Renal Injury Is Ameliorated by Sulforaphane via Activation of Transcription Factor NRF2
Antioxidants 2022, 11(1), 156; https://doi.org/10.3390/antiox11010156 - 14 Jan 2022
Viewed by 554
Abstract
Age is one of the major risk factors for the development of chronic pathologies, including kidney diseases. Oxidative stress and mitochondrial dysfunction play a pathogenic role in aging kidney disease. Transcription factor NRF2, a master regulator of redox homeostasis, is altered during aging, [...] Read more.
Age is one of the major risk factors for the development of chronic pathologies, including kidney diseases. Oxidative stress and mitochondrial dysfunction play a pathogenic role in aging kidney disease. Transcription factor NRF2, a master regulator of redox homeostasis, is altered during aging, but the exact implications of altered NRF2 signaling on age-related renal mitochondrial impairment are not yet clear. Herein, we investigated the role of sulforaphane, a well-known NRF2 activator, on age-related mitochondrial and kidney dysfunction. Young (2–4 month) and aged (20–24 month) male Fischer 344 rats were treated with sulforaphane (15 mg/kg body wt/day) in drinking water for four weeks. We observed significant impairment in renal cortical mitochondrial function along with perturbed redox homeostasis, decreased kidney function and marked impairment in NRF2 signaling in aged Fischer 344 rats. Sulforaphane significantly improved mitochondrial function and ameliorated kidney injury by increasing cortical NRF2 expression and activity and decreasing protein expression of KEAP1, an NRF2 repressor. Sulforaphane treatment did not affect the renal NRF2 expression or activity and mitochondrial function in young rats. Taken together, our results provide novel insights into the protective role of the NRF2 pathway in kidneys during aging and highlight the therapeutic potential of sulforaphane in mitigating kidney dysfunction in elders. Full article
(This article belongs to the Special Issue NRF2 in Health and Diseases)
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Article
Fermentation with Tea Residues Enhances Antioxidant Activities and Polyphenol Contents in Kombucha Beverages
Antioxidants 2022, 11(1), 155; https://doi.org/10.3390/antiox11010155 - 14 Jan 2022
Cited by 1 | Viewed by 707
Abstract
Kombucha is a popular beverage with various bioactivities (such as antioxidant activity), which can be attributed to its abundant bioactive compounds, especially polyphenols. Kombucha is conventionally prepared by fermentation of a sugared black tea infusion without tea residue. In this study, the effects [...] Read more.
Kombucha is a popular beverage with various bioactivities (such as antioxidant activity), which can be attributed to its abundant bioactive compounds, especially polyphenols. Kombucha is conventionally prepared by fermentation of a sugared black tea infusion without tea residue. In this study, the effects of black tea residue and green tea residue on kombucha were studied, and its antioxidant activities, total phenolic contents, as well as concentrations of polyphenols at different fermentation stages were evaluated using ferric-reducing antioxidant power, Trolox equivalent antioxidant capacity, Folin-Ciocalteu method and high-performance liquid chromatography with a photodiode array detector. The results showed that fermentation with tea residue could markedly increase antioxidant activities (maximum 3.25 times) as well as polyphenolic concentrations (5.68 times) of kombucha. In addition, green tea residue showed a stronger effect than black tea residue. Overall, it is interesting to find that fermentation with tea residues could be a better strategy to produce polyphenol-rich kombucha beverages. Full article
(This article belongs to the Special Issue Antioxidants and Bioactive Compounds in Fermented Foods)
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Article
GlyNAC (Glycine and N-Acetylcysteine) Supplementation Improves Impaired Mitochondrial Fuel Oxidation and Lowers Insulin Resistance in Patients with Type 2 Diabetes: Results of a Pilot Study
Antioxidants 2022, 11(1), 154; https://doi.org/10.3390/antiox11010154 - 13 Jan 2022
Cited by 1 | Viewed by 815
Abstract
Patients with type 2 diabetes (T2D) are known to have mitochondrial dysfunction and increased insulin resistance (IR), but the underlying mechanisms are not well understood. We reported previously that (a) adequacy of the antioxidant glutathione (GSH) is necessary for optimal mitochondrial fatty-acid oxidation [...] Read more.
Patients with type 2 diabetes (T2D) are known to have mitochondrial dysfunction and increased insulin resistance (IR), but the underlying mechanisms are not well understood. We reported previously that (a) adequacy of the antioxidant glutathione (GSH) is necessary for optimal mitochondrial fatty-acid oxidation (MFO); (b) supplementing the GSH precursors glycine and N-acetylcysteine (GlyNAC) in mice corrected GSH deficiency, reversed impaired MFO, and lowered oxidative stress (OxS) and IR; and (c) supplementing GlyNAC in patients with T2D improved GSH synthesis and concentrations, and lowered OxS. However, the effect of GlyNAC on MFO, MGO (mitochondrial glucose oxidation), IR and plasma FFA (free-fatty acid) concentrations in humans with T2D remains unknown. This manuscript reports the effect of supplementing GlyNAC for 14-days on MFO, MGO, IR and FFA in 10 adults with T2D and 10 unsupplemented non-diabetic controls. Fasted T2D participants had 36% lower MFO (p < 0.001), 106% higher MGO (p < 0.01), 425% higher IR (p < 0.001) and 76% higher plasma FFA (p < 0.05). GlyNAC supplementation significantly improved fasted MFO by 30% (p < 0.001), lowered MGO by 47% (p < 0.01), decreased IR by 22% (p < 0.01) and lowered FFA by 25% (p < 0.01). These results provide proof-of-concept that GlyNAC supplementation could improve mitochondrial dysfunction and IR in patients with T2D, and warrant additional research. Full article
(This article belongs to the Special Issue Antioxidants in Human Health and Disease)
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Review
Chemical Stability of Ascorbic Acid Integrated into Commercial Products: A Review on Bioactivity and Delivery Technology
Antioxidants 2022, 11(1), 153; https://doi.org/10.3390/antiox11010153 - 13 Jan 2022
Viewed by 649
Abstract
The L-enantiomer of ascorbic acid is commonly known as vitamin C. It is an indispensable nutrient and plays a key role in retaining the physiological process of humans and animals. L-gulonolactone oxidase, the key enzyme for the de novo synthesis of ascorbic acid, [...] Read more.
The L-enantiomer of ascorbic acid is commonly known as vitamin C. It is an indispensable nutrient and plays a key role in retaining the physiological process of humans and animals. L-gulonolactone oxidase, the key enzyme for the de novo synthesis of ascorbic acid, is lacking in some mammals including humans. The functionality of ascorbic acid has prompted the development of foods fortified with this vitamin. As a natural antioxidant, it is expected to protect the sensory and nutritional characteristics of the food. It is thus important to know the degradation of ascorbic acid in the food matrix and its interaction with coexisting components. The biggest challenge in the utilization of ascorbic acid is maintaining its stability and improving its delivery to the active site. The review also includes the current strategies for stabilizing ascorbic acid and the commercial applications of ascorbic acid. Full article
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Article
Genetic Polymorphisms of MnSOD Modify the Impacts of Environmental Melamine on Oxidative Stress and Early Kidney Injury in Calcium Urolithiasis Patients
Antioxidants 2022, 11(1), 152; https://doi.org/10.3390/antiox11010152 - 13 Jan 2022
Viewed by 386
Abstract
Environmental melamine exposure increases the risks of oxidative stress and early kidney injury. Manganese superoxide dismutase (MnSOD), glutathione peroxidase, and catalase can protect the kidneys against oxidative stress and maintain normal function. We evaluated whether their single-nucleotide polymorphisms (SNPs) could modify melamine’s effects. [...] Read more.
Environmental melamine exposure increases the risks of oxidative stress and early kidney injury. Manganese superoxide dismutase (MnSOD), glutathione peroxidase, and catalase can protect the kidneys against oxidative stress and maintain normal function. We evaluated whether their single-nucleotide polymorphisms (SNPs) could modify melamine’s effects. A total of 302 patients diagnosed with calcium urolithiasis were enrolled. All patients provided one-spot overnight urine samples to measure their melamine levels, urinary biomarkers of oxidative stress and renal tubular injury. Median values were used to dichotomize levels into high and low. Subjects carrying the T allele of rs4880 and high melamine levels had 3.60 times greater risk of high malondialdehyde levels than those carrying the C allele of rs4880 and low melamine levels after adjustment. Subjects carrying the G allele of rs5746136 and high melamine levels had 1.73 times greater risk of high N-Acetyl-β-d-glucosaminidase levels than those carrying the A allele of rs5746136 and low melamine levels. In conclusion, the SNPs of MnSOD, rs4880 and rs5746136, influence the risk of oxidative stress and renal tubular injury, respectively, in calcium urolithiasis patients. In the context of high urinary melamine levels, their effects on oxidative stress and renal tubular injury were further increased. Full article
(This article belongs to the Special Issue Oxidative Stress in Human Toxicology)
Article
The Role of H2O2-Scavenging Enzymes (Ascorbate Peroxidase and Catalase) in the Tolerance of Lemna minor to Antibiotics: Implications for Phytoremediation
Antioxidants 2022, 11(1), 151; https://doi.org/10.3390/antiox11010151 - 13 Jan 2022
Viewed by 839
Abstract
We investigated the individual and combined contributions of two distinct heme proteins namely, ascorbate peroxidase (APX) and catalase (CAT) on the tolerance of Lemna minor plants to antibiotics. For our investigation, we used specific inhibitors of these two H2O2-scavenging [...] Read more.
We investigated the individual and combined contributions of two distinct heme proteins namely, ascorbate peroxidase (APX) and catalase (CAT) on the tolerance of Lemna minor plants to antibiotics. For our investigation, we used specific inhibitors of these two H2O2-scavenging enzymes (p-aminophenol, 3-amino,1,2,4-triazole, and salicylic acid). APX activity was central for the tolerance of this aquatic plant to amoxicillin (AMX), whereas CAT activity was important for avoiding oxidative damage when exposed to ciprofloxacin (CIP). Both monitored enzymes had important roles in the tolerance of Lemna minor to erythromycin (ERY). The use of molecular kinetic approaches to detect and increase APX and/or CAT scavenging activities could enhance tolerance, and, therefore, improve the use of L. minor plants to reclaim antibiotics from water bodies. Full article
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Review
Can Polyphenols Inhibit Ferroptosis?
Antioxidants 2022, 11(1), 150; https://doi.org/10.3390/antiox11010150 - 12 Jan 2022
Viewed by 650
Abstract
Polyphenols, a diverse group of naturally occurring molecules commonly found in higher plants, have been heavily investigated over the last two decades due to their potent biological activities—among which the most important are their antioxidant, antimicrobial, anticancer, anti-inflammatory and neuroprotective activities. A common [...] Read more.
Polyphenols, a diverse group of naturally occurring molecules commonly found in higher plants, have been heavily investigated over the last two decades due to their potent biological activities—among which the most important are their antioxidant, antimicrobial, anticancer, anti-inflammatory and neuroprotective activities. A common route of polyphenol intake in humans is through the diet. Since they are subjected to excessive metabolism in vivo it has been questioned whether their much-proven in vitro bioactivity could be translated to in vivo systems. Ferroptosis is a newly introduced, iron-dependent, regulated mode of oxidative cell death, characterized by increased lipid peroxidation and the accumulation of toxic lipid peroxides, which are considered to be toxic reactive oxygen species. There is a growing body of evidence that ferroptosis is involved in the development of almost all chronic diseases. Thus, ferroptosis is considered a new therapeutic target for offsetting many diseases, and researchers are putting great expectations on this field of research and medicine. The aim of this review is to critically analyse the potential of polyphenols to modulate ferroptosis and whether they can be considered promising compounds for the alleviation of chronic conditions. Full article
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Review
Nrf2 in the Field of Dentistry with Special Attention to NLRP3
Antioxidants 2022, 11(1), 149; https://doi.org/10.3390/antiox11010149 - 12 Jan 2022
Cited by 2 | Viewed by 663
Abstract
The aim of this review article was to summarize the functional implications of the nuclear factor E2-related factor or nuclear factor (erythroid-derived 2)-like 2 (Nrf2), with special attention to the NACHT (nucleotide-binding oligomerization), LRR (leucine-rich repeat), and PYD (pyrin domain) domains-containing protein 3 [...] Read more.
The aim of this review article was to summarize the functional implications of the nuclear factor E2-related factor or nuclear factor (erythroid-derived 2)-like 2 (Nrf2), with special attention to the NACHT (nucleotide-binding oligomerization), LRR (leucine-rich repeat), and PYD (pyrin domain) domains-containing protein 3 (NLRP3) inflammasome in the field of dentistry. NLRP3 plays a crucial role in the progression of inflammatory and adaptive immune responses throughout the body. It is already known that this inflammasome is a key regulator of several systemic diseases. The initiation and activation of NLRP3 starts with the oral microbiome and its association with the pathogenesis and progression of several oral diseases, including periodontitis, periapical periodontitis, and oral squamous cell carcinoma (OSCC). The possible role of the inflammasome in oral disease conditions may involve the aberrant regulation of various response mechanisms, not only in the mouth but in the whole body. Understanding the cellular and molecular biology of the NLRP3 inflammasome and its relationship to Nrf2 is necessary for the rationale when suggesting it as a potential therapeutic target for treatment and prevention of oral inflammatory and immunological disorders. In this review, we highlighted the current knowledge about NLRP3, its likely role in the pathogenesis of various inflammatory oral processes, and its crosstalk with Nrf2, which might offer future possibilities for disease prevention and targeted therapy in the field of dentistry and oral health. Full article
(This article belongs to the Special Issue NRF2 in Health and Diseases)
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Article
Dietary Vitamin A Improved the Flesh Quality of Grass Carp (Ctenopharyngodon idella) in Relation to the Enhanced Antioxidant Capacity through Nrf2/Keap 1a Signaling Pathway
Antioxidants 2022, 11(1), 148; https://doi.org/10.3390/antiox11010148 - 12 Jan 2022
Cited by 1 | Viewed by 587
Abstract
Fish is an important animal-source food for humans. However, the oxidative stress-induced by intensive aquaculture usually causes deterioration of fish meat quality. The nutritional way has been considered to be a useful method for improving fish flesh quality. This study using the same [...] Read more.
Fish is an important animal-source food for humans. However, the oxidative stress-induced by intensive aquaculture usually causes deterioration of fish meat quality. The nutritional way has been considered to be a useful method for improving fish flesh quality. This study using the same growth experiment as our previous study was conducted to investigate whether vitamin A could improve flesh quality by enhancing antioxidative ability via Nrf2/Keap1 signaling in fish muscle. Six diets with different levels of vitamin A were fed to grass carp (Ctenopharyngodon idella) (262.02 ± 0.45 g) for 10 weeks. Dietary vitamin A significantly improved flesh sensory appeal and nutritional value, as evident by higher pH24h value, water-holding capacity, shear force, contents of protein, lipid, four indispensable amino acids (lysine, methionine, threonine, and arginine) and total polyunsaturated fatty acid in the muscle. Furthermore, dietary vitamin A reduced oxidative damage, as evident by decreased levels of muscle reactive oxygen species, malondialdehyde, and protein carbonyl, enhanced activities of antioxidative enzyme (catalase, copper/zinc superoxide dismutase (CuZnSOD), MnSOD, glutathione peroxidase, and glutathione reductase), as well as increased content of glutathione, which was probably in relation to the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling. These findings demonstrated that dietary vitamin A improved flesh quality probably by enhancing antioxidant ability through Nrf2/Keap 1a signaling in fish. Full article
(This article belongs to the Special Issue Antioxidants in Animal Feed)
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Article
Sodium Thiosulfate Improves Hypertension in Rats with Adenine-Induced Chronic Kidney Disease
Antioxidants 2022, 11(1), 147; https://doi.org/10.3390/antiox11010147 - 11 Jan 2022
Viewed by 432
Abstract
Hypertension is highly prevalent in chronic kidney disease (CKD). Hydrogen sulfide (H2S) is an endogenously produced gasotransmitter with vasodilator properties. We, hence, investigated whether oral administration of sodium thiosulfate (STS), a clinically applicable H2S-based therapy, can exert a protective [...] Read more.
Hypertension is highly prevalent in chronic kidney disease (CKD). Hydrogen sulfide (H2S) is an endogenously produced gasotransmitter with vasodilator properties. We, hence, investigated whether oral administration of sodium thiosulfate (STS), a clinically applicable H2S-based therapy, can exert a protective effect against hypertension in an adenine-induced CKD rat model. Eight-week-old male Sprague–Dawley rats were fed with 0.5% adenine chow for 3 weeks to induce CKD. After 1 week, the rats were divided into two groups: one without and one with STS (2 g/kg body weight/day) in drinking water for 2 weeks. Treatment with STS lowered systolic and diastolic blood pressure by 7 and 9 mm Hg, respectively. Renal H2S-generating enzyme expression was inhibited by CKD, while STS therapy increased plasma levels of H2S and thiosulfate. Additionally, restoration of nitric oxide bioavailability and rebalance of the renin–angiotensin system may contribute to the protective effects of STS. Our data suggest that the oral administration of STS improves hypertension in an adenine-induced CKD model, which brings us closer to the clinical translation of H2S-targeting therapy in CKD-induced hypertension. Full article
(This article belongs to the Special Issue Role of Hydrogen Sulfide in Health and Disease)
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