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Antioxidants
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Enzymatic and Non-Enzymatic Molecules with Antioxidant Function
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Enzymatic and Non-Enzymatic Molecules with Antioxidant Function

A special issue of Antioxidants (ISSN 2076-3921). This special issue belongs to the section "Antioxidant Enzyme Systems".

Deadline for manuscript submissions: closed (30 September 2020) | Viewed by 70463

Special Issue Editors

Dr. Paola Irato

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Guest Editor
Department of Biology, University of Padova, Padua, Italy
Interests: physiological responses of animals to environmental conditions where there are chemical contaminants that can also induce oxidative stress
Special Issues, Collections and Topics in MDPI journals
Dr. Gianfranco Santovito

E-Mail Website
Co-Guest Editor
Department of Biology, University of Padova, 35122 Padova, Italy
Interests: antioxidant defenses; climate change; molecular evolution; physiological responses to stress
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Reactive oxygen species (ROS) are naturally produced during several cellular pathways of aerobic metabolism, including oxidative phosphorylation, electron transport chains in mitochondria, the activity of oxido-reductase enzymes, and immunological reactions, such as phagocytosis. Although in subtoxic concentrations, these molecules may act as second messengers in intracellular signal transduction pathways, and small deviations in their physiological concentrations can have dramatic effects, causing toxic insults to lipids, proteins, and DNA. Under basal conditions, the adverse effects of oxyradicals are prevented by the antioxidant system, consisting of a wide array of low molecular weight scavengers and antioxidant enzymes, which defend the cells against excess production of ROS and the risk of oxidative stress. A good antioxidant should: (1) specifically quench free radicals; (2) chelate redox metals; (3) interact with other antioxidants within the “antioxidant network”; (4) have a positive effect on gene expression; (5) be readily absorbed; and (6) work in both the aqueous and/or membrane domains.

This Special Issue examines some of the aspects surrounding the fields of oxidative stress risk and ROS scavenging, including gene expression and molecular evolution of antioxidant proteins, physiological responses and pathological effects of ROS, and ecotoxicological application of antioxidant biomarkers. Discussions of the various protective pathways that may be provided by the antioxidant network against oxidative damage are addressed.

Dr. Paola Irato
Dr. Gianfranco Santovito
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Antioxidants is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • reactive oxygen species
  • oxidative stress
  • antioxidant enzymes
  • non-enzymatic antioxidant molecules

Published Papers (17 papers)

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Editorial

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4 pages, 200 KiB  
Editorial
Enzymatic and Non-Enzymatic Molecules with Antioxidant Function
by Paola Irato and Gianfranco Santovito
Antioxidants 2021, 10(4), 579; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10040579 - 09 Apr 2021
Cited by 86 | Viewed by 7994
Abstract
It is well known that the excessive production of reactive oxygen species (ROS) can lead to the peroxidation of membrane lipids, glycation/oxidation/nitration of proteins, inactivation of enzymes, DNA mutation and damage, and other alterations in the subcellular components [...] Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)

Research

Jump to: Editorial, Review

17 pages, 3556 KiB  
Article
Parallel Molecular Evolution of Catalases and Superoxide Dismutases—Focus on Thermophilic Fungal Genomes
by Katarína Chovanová, Miroslav Böhmer, Andrej Poljovka, Jaroslav Budiš, Jana Harichová, Tomáš Szemeš and Marcel Zámocký
Antioxidants 2020, 9(11), 1047; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9111047 - 27 Oct 2020
Cited by 11 | Viewed by 5254
Abstract
Catalases (CAT) and superoxide dismutases (SOD) represent two main groups of enzymatic antioxidants that are present in almost all aerobic organisms and even in certain anaerobes. They are closely interconnected in the catabolism of reactive oxygen species because one product of SOD reaction [...] Read more.
Catalases (CAT) and superoxide dismutases (SOD) represent two main groups of enzymatic antioxidants that are present in almost all aerobic organisms and even in certain anaerobes. They are closely interconnected in the catabolism of reactive oxygen species because one product of SOD reaction (hydrogen peroxide) is the main substrate of CAT reaction finally leading to harmless products (i.e., molecular oxygen and water). It is therefore interesting to compare the molecular evolution of corresponding gene families. We have used a phylogenomic approach to elucidate the evolutionary relationships among these two main enzymatic antioxidants with a focus on the genomes of thermophilic fungi. Distinct gene families coding for CuZnSODs, FeMnSODs, and heme catalases are very abundant in thermophilic Ascomycota. Here, the presented results demonstrate that whereas superoxide dismutase genes remained rather constant during long-term evolution, the total count of heme catalase genes was reduced in thermophilic fungi in comparison with their mesophilic counterparts. We demonstrate here, for the newly discovered ascomycetous genes coding for thermophilic superoxide dismutases and catalases (originating from our sequencing project), the expression patterns of corresponding mRNA transcripts and further analyze translated protein sequences. Our results provide important implications for the physiology of reactive oxygen species metabolism in eukaryotic cells at elevated temperatures. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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13 pages, 2377 KiB  
Article
The Industrial Organism Corynebacterium glutamicum Requires Mycothiol as Antioxidant to Resist Against Oxidative Stress in Bioreactor Cultivations
by Fabian Stefan Franz Hartmann, Lina Clermont, Quach Ngoc Tung, Haike Antelmann and Gerd Michael Seibold
Antioxidants 2020, 9(10), 969; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9100969 - 09 Oct 2020
Cited by 11 | Viewed by 3758
Abstract
In aerobic environments, bacteria are exposed to reactive oxygen species (ROS). To avoid an excess of ROS, microorganisms are equipped with powerful enzymatic and non-enzymatic antioxidants. Corynebacterium glutamicum, a widely used industrial platform organism, uses mycothiol (MSH) as major low molecular weight [...] Read more.
In aerobic environments, bacteria are exposed to reactive oxygen species (ROS). To avoid an excess of ROS, microorganisms are equipped with powerful enzymatic and non-enzymatic antioxidants. Corynebacterium glutamicum, a widely used industrial platform organism, uses mycothiol (MSH) as major low molecular weight (LMW) thiol and non-enzymatic antioxidant. In aerobic bioreactor cultivations, C. glutamicum becomes exposed to oxygen concentrations surpassing the air saturation, which are supposed to constitute a challenge for the intracellular MSH redox balance. In this study, the role of MSH was investigated at different oxygen levels (pO2) in bioreactor cultivations in C. glutamicum. Despite the presence of other highly efficient antioxidant systems, such as catalase, the MSH deficient ΔmshC mutant was impaired in growth in bioreactor experiments performed at pO2 values of 30%. At a pO2 level of 20%, this growth defect was abolished, indicating a high susceptibility of the MSH-deficient mutant towards elevated oxygen concentrations. Bioreactor experiments with C. glutamicum expressing the Mrx1-roGFP2 redox biosensor revealed a strong oxidative shift in the MSH redox potential (EMSH) at pO2 values above 20%. This indicates that the LMW thiol MSH is an essential antioxidant to maintain the robustness and industrial performance of C. glutamicum during aerobic fermentation processes. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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15 pages, 2323 KiB  
Article
Molecular Characterization, Protein–Protein Interaction Network, and Evolution of Four Glutathione Peroxidases from Tetrahymena thermophila
by Diana Ferro, Rigers Bakiu, Sandra Pucciarelli, Cristina Miceli, Adriana Vallesi, Paola Irato and Gianfranco Santovito
Antioxidants 2020, 9(10), 949; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9100949 - 02 Oct 2020
Cited by 14 | Viewed by 2850
Abstract
Glutathione peroxidases (GPxs) form a broad family of antioxidant proteins essential for maintaining redox homeostasis in eukaryotic cells. In this study, we used an integrative approach that combines bioinformatics, molecular biology, and biochemistry to investigate the role of GPxs in reactive oxygen species [...] Read more.
Glutathione peroxidases (GPxs) form a broad family of antioxidant proteins essential for maintaining redox homeostasis in eukaryotic cells. In this study, we used an integrative approach that combines bioinformatics, molecular biology, and biochemistry to investigate the role of GPxs in reactive oxygen species detoxification in the unicellular eukaryotic model organism Tetrahymena thermophila. Both phylogenetic and mechanistic empirical model analyses provided indications about the evolutionary relationships among the GPXs of Tetrahymena and the orthologous enzymes of phylogenetically related species. In-silico gene characterization and text mining were used to predict the functional relationships between GPxs and other physiologically-relevant processes. The GPx genes contain conserved transcriptional regulatory elements in the promoter region, which suggest that transcription is under tight control of specialized signaling pathways. The bioinformatic findings were next experimentally validated by studying the time course of gene transcription and enzymatic activity after copper (Cu) exposure. Results emphasize the role of GPxs in the detoxification pathways that, by complex regulation of GPx gene expression, enable Tethraymena to survive in high Cu concentrations and the associated redox environment. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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16 pages, 2501 KiB  
Article
Catalase T-Deficient Fission Yeast Meiocytes Show Resistance to Ionizing Radiation
by Razan Muhtadi, Alexander Lorenz, Samantha J. Mpaulo, Christian Siebenwirth and Harry Scherthan
Antioxidants 2020, 9(9), 881; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9090881 - 17 Sep 2020
Cited by 2 | Viewed by 2700
Abstract
Environmental stress, reactive oxygen species (ROS), or ionizing radiation (IR) can induce adverse effects in organisms and their cells, including mutations and premature aging. DNA damage and its faulty repair can lead to cell death or promote cancer through the accumulation of mutations. [...] Read more.
Environmental stress, reactive oxygen species (ROS), or ionizing radiation (IR) can induce adverse effects in organisms and their cells, including mutations and premature aging. DNA damage and its faulty repair can lead to cell death or promote cancer through the accumulation of mutations. Misrepair in germ cells is particularly dangerous as it may lead to alterations in developmental programs and genetic disease in the offspring. DNA damage pathways and radical defense mechanisms mediate resistance to genotoxic stresses. Here, we investigated, in the fission yeast Schizosaccharomyces pombe, the role of the H2O2-detoxifying enzyme cytosolic catalase T (Ctt1) and the Fe2+/Mn2+ symporter Pcl1 in protecting meiotic chromosome dynamics and gamete formation from radicals generated by ROS and IR. We found that wild-type and pcl1-deficient cells respond similarly to X ray doses of up to 300 Gy, while ctt1∆ meiocytes showed a moderate sensitivity to IR but a hypersensitivity to hydrogen peroxide with cells dying at >0.4 mM H2O2. Meiocytes deficient for pcl1, on the other hand, showed a resistance to hydrogen peroxide similar to that of the wild type, surviving doses >40 mM. In all, it appears that in the absence of the main H2O2-detoxifying pathway S. pombe meiocytes are able to survive significant doses of IR-induced radicals. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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18 pages, 2736 KiB  
Article
Effects of Moringa oleifera Leaf Extract on Diabetes-Induced Alterations in Paraoxonase 1 and Catalase in Rats Analyzed through Progress Kinetic and Blind Docking
by Erick Sierra-Campos, Mónica Valdez-Solana, Claudia Avitia-Domínguez, Mara Campos-Almazán, Ismael Flores-Molina, Guadalupe García-Arenas and Alfredo Téllez-Valencia
Antioxidants 2020, 9(9), 840; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9090840 - 08 Sep 2020
Cited by 12 | Viewed by 5077
Abstract
In our study, we aimed to evaluate the effects of Moringa oleifera leaves extract on rat paraoxonase 1 (rPON1) and catalase (rCAT) activities in alloxan-induced diabetic rats. Our study included three groups; group C (control, n = 5); group D (diabetic, n = [...] Read more.
In our study, we aimed to evaluate the effects of Moringa oleifera leaves extract on rat paraoxonase 1 (rPON1) and catalase (rCAT) activities in alloxan-induced diabetic rats. Our study included three groups; group C (control, n = 5); group D (diabetic, n = 5); and group DM (M. oleifera extract-supplemented diabetic rats, n = 5). Daily oral administration of M. oleifera extract at 200 mg/kg doses produced an increase in endogenous antioxidants. Serum rPON1 (lactonase) and liver cytosol catalase activities were determined by a spectrophotometric assay using progress curve analysis. We found a decrease in the Vm value of rPON1 in diabetic rats, but dihydrocoumarin (DHC) affinity (Km) was slightly increased. The value of Vm for the DM group was found to be reduced approximately by a factor of 3 compared with those obtained for group C, whereas Km was largely changed (96 times). Catalase activity was significantly higher in the DM group. These data suggest that the activation of rPON1 and rCAT activities by M. oleifera extracts may be mediated via the effect of the specific flavonoids on the enzyme structure. In addition, through molecular blind docking analysis, rPON1 was found to have two binding sites for flavonoids. In contrast, flavonoids bound at four sites in rCAT. In conclusion, the data suggest that compounds from M. oleifera leaves extract were able to influence the catalytic activities of both enzymes to compensate for the changes provoked by diabetes in rats. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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11 pages, 1719 KiB  
Article
Platelet-Rich Fibrin Can Neutralize Hydrogen Peroxide-Induced Cell Death in Gingival Fibroblasts
by Zahra Kargarpour, Jila Nasirzade, Francesca Di Summa, Layla Panahipour, Richard J. Miron and Reinhard Gruber
Antioxidants 2020, 9(6), 560; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9060560 - 26 Jun 2020
Cited by 17 | Viewed by 3397
Abstract
Hydrogen peroxide is a damage signal at sites of chronic inflammation. The question arises whether platelet-rich fibrin (PRF), platelet-poor plasma (PPP), and the buffy coat can neutralize hydrogen peroxide toxicity and thereby counteract local oxidative stress. In the present study, gingival fibroblasts cells [...] Read more.
Hydrogen peroxide is a damage signal at sites of chronic inflammation. The question arises whether platelet-rich fibrin (PRF), platelet-poor plasma (PPP), and the buffy coat can neutralize hydrogen peroxide toxicity and thereby counteract local oxidative stress. In the present study, gingival fibroblasts cells were exposed to hydrogen peroxide with and without lysates obtained from PRF membranes, PPP, heated PPP (75 °C for 10 min), and the buffy coat. Cell viability was examined by trypan blue staining, live-dead staining, and formazan crystal formation. Cell apoptosis was assessed by cleaved caspase-3 Western blot analysis. Reverse transcription-quantitative polymerase chain reaction (RT-PCR) was utilized to determine the impact of PRF lysates on the expression of catalase in fibroblasts. It was reported that lysates from PRF, PPP, and the buffy coat—but not heated PPP—abolished the hydrogen peroxide-induced toxicity in gingival fibroblasts. Necrosis was confirmed by a loss of membrane integrity and apoptosis was ruled out by the lack of cleavage of caspase-3. Aminotriazole, an inhibitor of catalase, reduced the cytoprotective activity of PRF lysates yet blocking of glutathione peroxidase by mercaptosuccinate did not show the same effect. PRF lysates had no impact on the expression of catalase in gingival fibroblasts. These findings suggest that PRF, PPP, and the buffy coat can neutralize hydrogen peroxide through the release of heat-sensitive catalase. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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14 pages, 2466 KiB  
Article
A Novel and Potentially Multifaceted Dehydroascorbate Reductase Increasing the Antioxidant Systems is Induced by Beauvericin in Tomato
by Martina Loi, Silvana De Leonardis, Giuseppina Mulè, Antonio F. Logrieco and Costantino Paciolla
Antioxidants 2020, 9(5), 435; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9050435 - 16 May 2020
Cited by 15 | Viewed by 3395
Abstract
Dehydroascorbate reductases (DHARs) are important enzymes that reconvert the dehydroascorbic acid (DHA) into ascorbic acid (ASC). They are involved in the plant response to oxidative stress, such as that induced by the mycotoxin beauvericin (BEA). Tomato plants were treated with 50 µM of [...] Read more.
Dehydroascorbate reductases (DHARs) are important enzymes that reconvert the dehydroascorbic acid (DHA) into ascorbic acid (ASC). They are involved in the plant response to oxidative stress, such as that induced by the mycotoxin beauvericin (BEA). Tomato plants were treated with 50 µM of BEA; the main antioxidant compounds and enzymes were evaluated. DHARs were analyzed in the presence of different electron donors by native and denaturing electrophoresis as well as by western blot and mass spectrometry to identify a novel induced protein with DHAR activity. Kinetic parameters for dehydroascorbate (DHA) and glutathione (GSH) were also determined. The novel DHAR was induced after BEA treatment. It was GSH-dependent and possessed lower affinity to DHA and GSH than the classical DHARs. Interestingly, the mass spectrometry analysis of the main band appearing on sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) revealed a chloroplast sedoheptulose 1,7-bisphosphatase, a key enzyme of the Calvin cycle, and a chloroplast mRNA-binding protein, suggesting that the DHA reducing capacity could be a side activity or the novel DHAR could be part of a protein complex. These results shed new light on the ascorbate-glutathione regulation network under oxidative stress and may represent a new way to increase the plant antioxidant defense system, plant nutraceutical value, and the health benefits of plant consumption. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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21 pages, 2223 KiB  
Article
Multi-Component Antioxidative System and Robust Carbohydrate Status, the Essence of Plant Arsenic Tolerance
by Monika Kofroňová, Aneta Hrdinová, Petra Mašková, Jana Tremlová, Petr Soudek, Šárka Petrová, Dominik Pinkas and Helena Lipavská
Antioxidants 2020, 9(4), 283; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9040283 - 27 Mar 2020
Cited by 31 | Viewed by 3127
Abstract
Arsenic (As) contaminates the food chain and decreases agricultural production through impairing plants, particularly due to oxidative stress. To better understand the As tolerance mechanisms, two contrasting tobacco genotypes: As-sensitive Nicotiana sylvestris and As-tolerant N.tabacum, cv. ‘Wisconsin’ were analyzed. The most meaningful [...] Read more.
Arsenic (As) contaminates the food chain and decreases agricultural production through impairing plants, particularly due to oxidative stress. To better understand the As tolerance mechanisms, two contrasting tobacco genotypes: As-sensitive Nicotiana sylvestris and As-tolerant N.tabacum, cv. ‘Wisconsin’ were analyzed. The most meaningful differences were found in the carbohydrate status, neglected so far in the As context. In the tolerant genotype, contrary to the sensitive one, net photosynthesis rates and saccharide levels were unaffected by As exposure. Importantly, the total antioxidant capacity was far stronger in the As-tolerant genotype, based on higher antioxidants levels (e.g., phenolics, ascorbate, glutathione) and activities and/or appropriate localizations of antioxidative enzymes, manifested as reverse root/shoot activities in the selected genotypes. Accordingly, malondialdehyde levels, a lipid peroxidation marker, increased only in sensitive tobacco, indicating efficient membrane protection in As-tolerant species. We bring new evidence of the orchestrated action of a broad spectrum of both antioxidant enzymes and molecules essential for As stress coping. For the first time, we propose robust carbohydrate metabolism based on undisturbed photosynthesis to be crucial not only for subsidizing C and energy for defense but also for participating in direct reactive oxygen species (ROS) quenching. The collected data and suggestions can serve as a basis for the selection of plant As phytoremediators or for targeted breeding of tolerant crops. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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19 pages, 3999 KiB  
Article
Global Evolutionary Analysis of 11 Gene Families Part of Reactive Oxygen Species (ROS) Gene Network in Four Eucalyptus Species
by Qiang Li, Hélène San Clemente, Yongrui He, Yongyao Fu and Christophe Dunand
Antioxidants 2020, 9(3), 257; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9030257 - 21 Mar 2020
Cited by 6 | Viewed by 2896
Abstract
Eucalyptus is a worldwide hard-wood species which increasingly focused on. To adapt to various biotic and abiotic stresses, Eucalyptus have evolved complex mechanisms, increasing the cellular concentration of reactive oxygen species (ROS) by numerous ROS controlling enzymes. To better analyse the ROS gene [...] Read more.
Eucalyptus is a worldwide hard-wood species which increasingly focused on. To adapt to various biotic and abiotic stresses, Eucalyptus have evolved complex mechanisms, increasing the cellular concentration of reactive oxygen species (ROS) by numerous ROS controlling enzymes. To better analyse the ROS gene network and discuss the differences between four Eucalyptus species, ROS gene network including 11 proteins families (1CysPrx, 2CysPrx, APx, APx-R, CIII Prx, Diox, GPx, Kat, PrxII, PrxQ and Rboh) were annotated and compared in an expert and exhaustive manner from the genomic data available from E. camaldulensis, E. globulus, E. grandis, and E. gunnii. In addition, a specific sequencing strategy was performed in order to determine if the missed sequences in at least one organism are the results of gain/loss events or only sequencing gaps. We observed that the automatic annotation applied to multigenic families is the source of miss-annotation. Base on the family size, the 11 families can be categorized into duplicated gene families (CIII Prx, Kat, 1CysPrx, and GPx), which contain a lot of gene duplication events and non-duplicated families (APx, APx-R, Rboh, DiOx, 2CysPrx, PrxII, and PrxQ). The gene family sizes are much larger in Eucalyptus than most of other angiosperms due to recent gene duplications, which could give higher adaptability to environmental changes and stresses. The cross-species comparative analysis shows gene gain and loss events during the evolutionary process. The 11 families possess different expression patterns, while in the Eucalyptus genus, the ROS families present similar expression patterns. Overall, the comparative analysis might be a good criterion to evaluate the adaptation of different species with different characters, but only if data mining is as exhaustive as possible. It is also a good indicator to explore the evolutionary process. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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20 pages, 2993 KiB  
Article
Some Physiological and Biochemical Mechanisms during Seed-to-Seedling Transition in Tomato as Influenced by Garlic Allelochemicals
by Sikandar Hayat, Husain Ahmad, Mubasher Nasir, Muhammad Numan Khan, Muhammad Ali, Kashif Hayat, Muhammad Ali Khan, Farmanullah Khan, Yongqing Ma and Zhihui Cheng
Antioxidants 2020, 9(3), 235; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9030235 - 12 Mar 2020
Cited by 18 | Viewed by 4099
Abstract
The effects of aqueous garlic extracts (AGEs), diallyl disulfide (DADS), and allicin (AAS) were investigated during seed-to-seedling transition of tomato. Independent bioassays were performed including seed priming with AGE (0, 100, and 200 µg∙mL−1), germination under the allelochemical influence of AGE, [...] Read more.
The effects of aqueous garlic extracts (AGEs), diallyl disulfide (DADS), and allicin (AAS) were investigated during seed-to-seedling transition of tomato. Independent bioassays were performed including seed priming with AGE (0, 100, and 200 µg∙mL−1), germination under the allelochemical influence of AGE, DADS, and AAS, and germination under volatile application of AGE. Noticeable differences in germination indices and seedling growth (particularly root growth and fresh weights) were observed in a dose-dependent manner. When germinated under 50 mM NaCl, seeds primed with AGE exhibited induced defense via antioxidant enzyme activities (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)), lipid peroxidation (malondialdehyde content (MDA)), and H2O2 scavenging. Enzyme-linked immunosorbent analysis (ELISA) of the endogenous phytohormones auxin (IAA), abscisic acid (ABA), cytokinin (ZR), and gibberellic acid (GA3) in the roots and shoots of the obtained seedlings and the relative expression levels of auxin-responsive protein (IAA2), like-auxin (LAX5), mitogen-activated protein kinase (MAPK7 and MPK2), respiratory burst oxidase homolog (RBOH1), CHI3 and SODCC1 suggested allelopathic functions in stimulating growth responses. Our findings suggest that garlic allelochemicals act as plant biostimulants to enhance auxin biosynthesis and transportation, resulting in root growth promotion. Additionally, the relative expressions of defense-related genes, antioxidant enzymes activities and phytohormonal regulations indicate activation of the defense responses in tomato seedlings resulting in better growth and development. These results, thus, provide a basis to understand the biological functions of garlic allelochemicals from the induced resistance perspective in plants. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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17 pages, 1682 KiB  
Article
Melatonin Mitigates Chilling-Induced Oxidative Stress and Photosynthesis Inhibition in Tomato Plants
by Meiling Wang, Shuoxin Zhang and Fei Ding
Antioxidants 2020, 9(3), 218; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9030218 - 06 Mar 2020
Cited by 80 | Viewed by 4212
Abstract
Melatonin has been demonstrated to play a variety of roles in plants. Of particular importance is its role as a potent antioxidative agent. In the present study, we generated melatonin-deficient tomato plants using virus-induced gene silencing (VIGS) approach and melatonin-rich tomato plants by [...] Read more.
Melatonin has been demonstrated to play a variety of roles in plants. Of particular importance is its role as a potent antioxidative agent. In the present study, we generated melatonin-deficient tomato plants using virus-induced gene silencing (VIGS) approach and melatonin-rich tomato plants by foliar application of melatonin. These tomato plants were used to assess the effect of melatonin on chilling-induced oxidative stress and chilling-induced photosynthesis inhibition. We found that melatonin deficiency increased accumulation of reactive oxygen species (ROS) and aggravated lipid peroxidation in chilling-stressed tomato leaves, while exogenous application of melatonin had the opposite effect. Under chilling stress, melatonin-deficient tomato plants showed impaired antioxidant capacity as evidenced by lower activities of antioxidant enzymes and decreased rations of reduced glutathione (GSH)/oxidized glutathione (GSSG) and reduced ascorbate (AsA)/oxidized ascorbate (DHA), compared with melatonin-rich tomato plants. Furthermore, suppression of melatonin biosynthesis led to more photosynthesis inhibition under the chilling condition and compromised the capability of subsequent photosynthesis recovery in tomato plants. In addition, melatonin-deficient tomato plants displayed less activity of an important Calvin-Benson cycle enzyme sedoheptulose-1,7-bisphosphatase (SBPase) than melatonin-rich tomato plants under chilling stress. Collectively, our data indicate that melatonin is critical for antioxidant capacity and redox balance and is in favor of photosynthesis in tomato plants under chilling stress. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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19 pages, 1557 KiB  
Article
Beneficial Impact of an Extract from the Berries of Aronia melanocarpa L. on the Oxidative-Reductive Status of the Submandibular Gland of Rats Exposed to Cadmium
by Adam Dąbrowski, Barbara M. Onopiuk, Halina Car, Paweł Onopiuk, Zofia N. Dąbrowska, Joanna Rogalska, Małgorzata M. Brzóska and Ewa Dąbrowska
Antioxidants 2020, 9(2), 185; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9020185 - 22 Feb 2020
Cited by 11 | Viewed by 4249
Abstract
Oxidative stress underlies the pathomechanisms of toxic action of cadmium (Cd), including its damaging impact on the oral cavity. This study investigated whether the administration of an extract from Aronia melanocarpa L. berries (AME), characterized by their strong antioxidative potential, may have a [...] Read more.
Oxidative stress underlies the pathomechanisms of toxic action of cadmium (Cd), including its damaging impact on the oral cavity. This study investigated whether the administration of an extract from Aronia melanocarpa L. berries (AME), characterized by their strong antioxidative potential, may have a beneficial impact on the oxidative-reductive status of the submandibular gland in an experimental model of low-level and moderate human environmental exposure to cadmium. The main markers of the antioxidative status (glutathione reductase, superoxide dismutase, catalase, reduced glutathione, total antioxidative status (TAS)), total oxidative status (TOS), oxidative stress index (OSI = TOS/TAS), and lipid peroxides, as well as cadmium concentration, were evaluated in the submandibular gland tissue of female Wistar rats who received a 0.1% aqueous AME and/or a diet containing 0, 1, and 5 mg Cd/kg for 3 and 10 months. The treatment with cadmium decreased the activities of antioxidative enzymes (29%–74%), reduced glutathione concentration (45%–52%), and TAS and increased TOS, resulting in the development of oxidative stress and enhanced concentration of lipid peroxides in the submandibular gland. The administration of AME at both levels of exposure to cadmium offered significant protection against these actions of this xenobiotic. After the 10 month exposure to the 1 and 5 mg Cd/kg diet, TAS was decreased by 77% and 83%, respectively, TOS, OSI, and lipid peroxides concentration were increased by 50% and 52%, respectively, 11.8-fold and 14.4-fold, respectively, and 2.3-fold and 4.3-fold, respectively, whereas, in the case of the extract co-administration, the values of these parameters did not differ compared to the control group. The results indicate that the consumption of aronia products under exposure to cadmium may have a beneficial impact on the oxidative-reductive status of the submandibular gland and prevent oxidative stress development and enhanced lipid peroxidation in this salivary gland. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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30 pages, 5791 KiB  
Article
Ecotype-Specific Pathways of Reactive Oxygen Species Deactivation in Facultative Metallophyte Silene vulgaris (Moench) Garcke Treated with Heavy Metals
by Ewa Muszyńska, Mateusz Labudda and Adam Kral
Antioxidants 2020, 9(2), 102; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9020102 - 24 Jan 2020
Cited by 14 | Viewed by 2414
Abstract
This research aimed to indicate mechanisms involved in protection against the imbalanced generation of reactive oxygen species (ROS) during heavy metals (HMs) exposition of Silene vulgaris ecotypes with different levels of metal tolerance. Specimens of non-metallicolous (NM), calamine (CAL), and serpentine (SER) ecotypes [...] Read more.
This research aimed to indicate mechanisms involved in protection against the imbalanced generation of reactive oxygen species (ROS) during heavy metals (HMs) exposition of Silene vulgaris ecotypes with different levels of metal tolerance. Specimens of non-metallicolous (NM), calamine (CAL), and serpentine (SER) ecotypes were treated in vitro with Zn, Pb, and Cd ions applied simultaneously in concentrations that reflected their contents in natural habitats of the CAL ecotype (1× HMs) and 2.5- or 5.0-times higher than the first one. Our findings confirmed the sensitivity of the NM ecotype and revealed that the SER ecotype was not fully adapted to the HM mixture, since intensified lipid peroxidation, ultrastructural alternations, and decline in photosynthetic pigments’ content were ascertained under HM treatment. These changes resulted from insufficient antioxidant defense mechanisms based only on ascorbate peroxidase (APX) activity assisted (depending on HMs concentration) by glutathione-S-transferase (GST) and peroxidase activity at pH 6.8 in the NM ecotype or by GST and guaiacol-type peroxidase in the SER one. In turn, CAL specimens showed a hormetic reaction to 1× HMs, which manifested by both increased accumulation of pigments and most non-enzymatic antioxidants and enhanced activity of catalase and enzymes from the peroxidase family (with the exception of APX). Interestingly, no changes in superoxide dismutase activity were noticed in metallicolous ecotypes. To sum up, the ROS scavenging pathways in S. vulgaris relied on antioxidants specific to the respective ecotypes, however the synthesis of polyphenols was proved to be a universal reaction to HMs. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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Review

Jump to: Editorial, Research

22 pages, 7296 KiB  
Review
The Pivotal Role of Adipocyte-Na K peptide in Reversing Systemic Inflammation in Obesity and COVID-19 in the Development of Heart Failure
by Zi-jian Xie, Joel Novograd, Yaakov Itzkowitz, Ariel Sher, Yosef D. Buchen, Komal Sodhi, Nader G. Abraham and Joseph I. Shapiro
Antioxidants 2020, 9(11), 1129; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9111129 - 14 Nov 2020
Cited by 6 | Viewed by 3596
Abstract
This review summarizes data from several laboratories that have demonstrated a role of the Na/K-ATPase, specifically its α1 subunit, in the generation of reactive oxygen species (ROS) via the negative regulator of Src. Together with Src and other signaling proteins, the Na/K-ATPase forms [...] Read more.
This review summarizes data from several laboratories that have demonstrated a role of the Na/K-ATPase, specifically its α1 subunit, in the generation of reactive oxygen species (ROS) via the negative regulator of Src. Together with Src and other signaling proteins, the Na/K-ATPase forms an oxidant amplification loop (NKAL), amplifies ROS, and participates in cytokines storm in obesity. The development of a peptide fragment of the α1 subunit, NaKtide, has been shown to negatively regulate Src. Several groups showed that the systemic administration of the cell permeable modification of NaKtide (pNaKtide) or its selective delivery to fat tissue—adipocyte specific expression of NaKtide—ameliorate the systemic elevation of inflammatory cytokines seen in chronic obesity. Severe acute respiratory syndrome – coronavirus 2 (SARS-CoV-2), the RNA Coronavirus responsible for the COVID-19 global pandemic, invades cells via the angiotensin converting enzyme 2 (ACE-2) receptor (ACE2R) that is appended in inflamed fat tissue and exacerbates the formation of the cytokines storm. Both obesity and heart and renal failure are well known risks for adverse outcomes in patients infected with COVID-19. White adipocytes express ACE-2 receptors in high concentration, especially in obese patients. Once the virus invades the white adipocyte cell, it creates a COVID19–porphyrin complex which degrades and produces free porphyrin and iron and increases ROS. The increased formation of ROS and activation of the NKAL results in a further potentiated formation of ROS production, and ultimately, adipocyte generation of more inflammatory mediators, leading to systemic cytokines storm and heart failure. Moreover, chronic obesity also results in the reduction of antioxidant genes such as heme oxygenase-1 (HO-1), increasing adipocyte susceptibility to ROS and cytokines. It is the systemic inflammation and cytokine storm which is responsible for many of the adverse outcomes seen with COVID-19 infections in obese subjects, leading to heart failure and death. This review will also describe the potential antioxidant drugs and role of NaKtide and their demonstrated antioxidant effect used as a major strategy for improving obesity and epicardial fat mediated heart failure in the context of the COVID pandemic. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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28 pages, 4038 KiB  
Review
The Universal Soldier: Enzymatic and Non-Enzymatic Antioxidant Functions of Serum Albumin
by Daria A. Belinskaia, Polina A. Voronina, Vladimir I. Shmurak, Mikhail A. Vovk, Anastasia A. Batalova, Richard O. Jenkins and Nikolay V. Goncharov
Antioxidants 2020, 9(10), 966; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9100966 - 09 Oct 2020
Cited by 51 | Viewed by 4822
Abstract
As a carrier of many biologically active compounds, blood is exposed to oxidants to a greater extent than the intracellular environment. Serum albumin plays a key role in antioxidant defence under both normal and oxidative stress conditions. This review evaluates data published in [...] Read more.
As a carrier of many biologically active compounds, blood is exposed to oxidants to a greater extent than the intracellular environment. Serum albumin plays a key role in antioxidant defence under both normal and oxidative stress conditions. This review evaluates data published in the literature and from our own research on the mechanisms of the enzymatic and non-enzymatic activities of albumin that determine its participation in redox modulation of plasma and intercellular fluid. For the first time, the results of numerous clinical, biochemical, spectroscopic and computational experiments devoted to the study of allosteric modulation of the functional properties of the protein associated with its participation in antioxidant defence are analysed. It has been concluded that it is fundamentally possible to regulate the antioxidant properties of albumin with various ligands, and the binding and/or enzymatic features of the protein by changing its redox status. The perspectives for using the antioxidant properties of albumin in practice are discussed. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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14 pages, 812 KiB  
Review
Copper Sources for Sod1 Activation
by Stefanie D. Boyd, Morgan S. Ullrich, Amelie Skopp and Duane D. Winkler
Antioxidants 2020, 9(6), 500; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox9060500 - 07 Jun 2020
Cited by 25 | Viewed by 4064
Abstract
Copper ions (i.e., copper) are a critical part of several cellular processes, but tight regulation of copper levels and trafficking are required to keep the cell protected from this highly reactive transition metal. Cu, Zn superoxide dismutase (Sod1) protects the cell from the [...] Read more.
Copper ions (i.e., copper) are a critical part of several cellular processes, but tight regulation of copper levels and trafficking are required to keep the cell protected from this highly reactive transition metal. Cu, Zn superoxide dismutase (Sod1) protects the cell from the accumulation of radical oxygen species by way of the redox cycling activity of copper in its catalytic center. Multiple posttranslational modification events, including copper incorporation, are reliant on the copper chaperone for Sod1 (Ccs). The high-affinity copper uptake protein (Ctr1) is the main entry point of copper into eukaryotic cells and can directly supply copper to Ccs along with other known intracellular chaperones and trafficking molecules. This review explores the routes of copper delivery that are utilized to activate Sod1 and the usefulness and necessity of each. Full article
(This article belongs to the Special Issue Enzymatic and Non-Enzymatic Molecules with Antioxidant Function)
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