Non-Enzymatic Antioxidant Molecules and Their Defense Mechanisms

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

Deadline for manuscript submissions: 30 September 2024 | Viewed by 2932

Special Issue Editors


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Guest Editor
College of Pharmacy, Chonnam National University, Gwangju, Republic of Korea
Interests: antioxidant; anticancer; anti-inflammatory; phytochemical; small molecule

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Guest Editor
Functional Biomaterial Research Center, Korea Research Institute of Bioscience and Biotechnology, 181 Ipsin-gil, Jeongeup-si 56212, Republic of Korea
Interests: natural products; antiviral drugs; anti-cancer; immune regulation; influenza virus; rotavirus

Special Issue Information

Dear Colleagues,

The imbalance between the production of reactive oxygen species (ROS) and the capacity of antioxidants to counteract the deleterious effects of oxidants, results in an increase of risk including multiple chronic disorders or cancer development. Various antioxidant enzymes and nonenzymatic antioxidants are engaged in the regulation of the oxidation/reduction (redox) balance. While enzymatic antioxidants function by converting oxidized metabolic products to hydrogen peroxide (H2O2) and then to water using cofactors through multi-step processes, nonenzymatic antioxidants intercept and terminate free radical chain reactions. Examples of nonenzymatic antioxidants are vitamin E, A, C, flavonoids, carotenoids, glutathione, plant polyphenols, uric acid, theaflavin, allyl sulfides, curcumin, melatonin, bilirubin, and polyamines. A better understanding of new aspects of well-known nonenzymatic antioxidants, discovery of new nonenzymatic antioxidants, and their interaction with the endogenous antioxidant signaling pathway would strengthen the relevance of their preventive or therapeutic use in health and diseases.

We invite researchers to submit research articles on new aspects of nonenzymatic antioxidants in the regulation of oxidative stresses and their action of mechanism. The topic includes the biological effects of non-enzymatic antioxidants and regulatory signaling pathway in the alleviation or prevention of chronic diseases.

Dr. Young‑Chang Cho
Dr. Su-Jin Park
Guest Editors

Manuscript Submission Information

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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

  • thiols
  • glutathione
  • vitamin C
  • tocopherols
  • phenols
  • flavonoids
  • carotenoids
  • plants
  • bacteria
  • fungi
  • animals
  • human health

Published Papers (2 papers)

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Research

18 pages, 3386 KiB  
Article
Exogenous Calcium Alleviates Oxidative Stress Caused by Salt Stress in Peanut Seedling Roots by Regulating the Antioxidant Enzyme System and Flavonoid Biosynthesis
by Yan Gao, Xuan Dong, Rongjin Wang, Fei Hao, Hui Zhang, Yongyong Zhang and Guolin Lin
Antioxidants 2024, 13(2), 233; https://doi.org/10.3390/antiox13020233 - 14 Feb 2024
Viewed by 866
Abstract
Soil salinity is one of the adversity stresses plants face, and antioxidant defense mechanisms play an essential role in plant resistance. We investigated the effects of exogenous calcium on the antioxidant defense system in peanut seedling roots that are under salt stress by [...] Read more.
Soil salinity is one of the adversity stresses plants face, and antioxidant defense mechanisms play an essential role in plant resistance. We investigated the effects of exogenous calcium on the antioxidant defense system in peanut seedling roots that are under salt stress by using indices including the transcriptome and absolute quantitative metabolome of flavonoids. Under salt stress conditions, the antioxidant defense capacity of enzymatic systems was weakened and the antioxidant capacity of the linked AsA-GSH cycle was effectively inhibited. In contrast, the ascorbate biosynthesis pathway and its upstream glycolysis metabolism pathway became active, which stimulated shikimate biosynthesis and the downstream phenylpropanoid metabolism pathway, resulting in an increased accumulation of flavonoids, which, as one of the antioxidants in the non-enzymatic system, provide hydroxyl radicals to scavenge the excess reactive oxygen species and maintain the plant’s vital activities. However, the addition of exogenous calcium caused changes in the antioxidant defense system in the peanut root system. The activity of antioxidant enzymes and the antioxidant capacity of the AsA-GSH cycle were enhanced. Therefore, glycolysis and phenylpropanoid metabolism do not exert antioxidant function, and flavonoids were no longer synthesized. In addition, antioxidant enzymes and the AsA-GSH cycle showed a trade-off relationship with sugars and flavonoids. Full article
(This article belongs to the Special Issue Non-Enzymatic Antioxidant Molecules and Their Defense Mechanisms)
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15 pages, 3230 KiB  
Article
6-Pentyl-α-Pyrone from Trichoderma gamsii Exert Antioxidant and Anti-Inflammatory Properties in Lipopolysaccharide-Stimulated Mouse Macrophages
by Jae Sung Lim, Joo-Hyun Hong, Da Young Lee, Xiangying Li, Da Eun Lee, Jeong Uk Choi, Kwang Youl Lee, Ki Hyun Kim and Young-Chang Cho
Antioxidants 2023, 12(12), 2028; https://doi.org/10.3390/antiox12122028 - 22 Nov 2023
Viewed by 878
Abstract
Filamentous fungi produce several beneficial secondary metabolites, including bioactive compounds, food additives, and biofuels. Trichoderma, which is a teleomorphic Hypocrea that falls under the taxonomic groups Ascomycota and Dikarya, is an extensively studied fungal genus. In an ongoing study that seeks to [...] Read more.
Filamentous fungi produce several beneficial secondary metabolites, including bioactive compounds, food additives, and biofuels. Trichoderma, which is a teleomorphic Hypocrea that falls under the taxonomic groups Ascomycota and Dikarya, is an extensively studied fungal genus. In an ongoing study that seeks to discover bioactive natural products, we investigated potential bioactive metabolites from the methanolic extract of cultured Trichoderma gamsii. Using liquid chromatography–mass spectrometry (LC–MS), one major compound was isolated and structurally identified as 6-pentyl-α-pyrone (6PP) based on nuclear magnetic resonance data and LC–MS analysis. To determine its antioxidant and anti-inflammatory activity, as well as the underlying mechanisms, we treated lipopolysaccharide (LPS)-stimulated Raw264.7 mouse macrophages with 6PP. We found that 6PP suppresses LPS-induced increase in the levels of nitric oxide, a mediator of oxidative stress and inflammation, and restores LPS-mediated depletion of total glutathione by stabilizing nuclear factor erythroid 2-related factor 2 (Nrf2), an antioxidative factor, and elevating heme oxygenase-1 levels. Furthermore, 6PP inhibited LPS-induced production of proinflammatory cytokines, which are, at least in part, regulated by heme oxygenase-1 (HO-1). 6PP suppressed proinflammatory responses by inhibiting the nuclear localization of nuclear factor kappa B (NF-κB), as well as by dephosphorylating the mitogen-activated protein kinases (MAPKs). These results indicate that 6PP can protect macrophages against oxidative stress and LPS-induced excessive inflammatory responses by activating the Nrf2/HO-1 pathway while inhibiting the proinflammatory, NF-κB, and MAPK pathways. Full article
(This article belongs to the Special Issue Non-Enzymatic Antioxidant Molecules and Their Defense Mechanisms)
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