Anthocyanins in leaves: light attenuators or antioxidants?

Anthocyanins have the potential to mitigate photooxidative injury in leaves, both by shielding chloroplasts from excess high-energy quanta, and by scavenging reactive oxygen species. To distinguish between the impacts of these two putative mechanisms, superoxide (O2•–) concentration and chlorophyll oxidation were measured for Lactuca sativa L. chloroplast suspensions under various light and antioxidant-supplemented environments. A red cellulose filter, the optical properties of which approximated that of anthocyanin, effected a 33% decline in rate of O2•– generation and 37% reduction in chlorophyll bleaching, when used to shield irradiated chloroplasts. Colourless and blue tautomers of cyanidin 3-(6-malonyl)glucoside at pH 7 removed up to 17% of O2•– generated by chloroplasts, indicating that cytosolic anthocyanins can serve as effective antioxidants. Red tautomers, typical of vacuolar anthocyanins, also showed strong reducing potentials as indicated by cyclic voltammetry. These potentials declined by 40% after 15 min exposure to O2•–. Maximum quantum efficiencies of photosynthesis were similar for red and green portions of intact L. sativa leaves, but the red regions were less photoinhibited, and recovered more extensively after exposures to strong light. Anthocyanins evidently offer effective and versatile protection to leaves without significantly compromising photosynthesis.

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Nature's Swiss Army Knife: The Diverse Protective Roles of Anthocyanins in Leaves

Journal of Biomedicine and Biotechnology ◽

10.1155/s1110724304406147 ◽

2004 ◽

Vol 2004 (5) ◽

pp. 314-320 ◽

Cited By ~ 389

Author(s):

Kevin S. Gould

Keyword(s):

Heavy Metals ◽

Reactive Oxygen Species ◽

Free Radicals ◽

Environmental Stress ◽

High Energy ◽

Deciduous Trees ◽

Oxygen Species ◽

Flavonoid Pathway ◽

Strong Light ◽

Plant Survival

Anthocyanins, the pigments responsible for spectacular displays of vermilion in the leaves of deciduous trees, have long been considered an extravagant waste of a plant's resources. Contemporary research, in contrast, has begun to show that the pigments can significantly influence the way a leaf responds to environmental stress. Anthocyanins have been implicated in tolerance to stressors as diverse as drought, UV-B, and heavy metals, as well as resistance to herbivores and pathogens. By absorbing high-energy quanta, anthocyanic cell vacuoles both protect chloroplasts from the photoinhibitory and photooxidative effects of strong light, and prevent the catabolism of photolabile defence compounds. Anthocyanins also mitigate photooxidative injury in leaves by efficiently scavenging free radicals and reactive oxygen species. Far from being a useless by-product of the flavonoid pathway, these red pigments may in some instances be critical for plant survival.

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Molecular Characterization of Reactive Oxygen Species in Myocardial Ischemia-Reperfusion Injury

BioMed Research International ◽

10.1155/2015/864946 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 75

Author(s):

Tingyang Zhou ◽

Chia-Chen Chuang ◽

Li Zuo

Keyword(s):

Reactive Oxygen Species ◽

Myocardial Ischemia ◽

Energy Demand ◽

Heart Diseases ◽

Ischemia Reperfusion ◽

Reactive Oxygen ◽

High Energy ◽

Protective Mechanism ◽

Oxygen Species ◽

Myocardial Ischemia Reperfusion

Myocardial ischemia-reperfusion (I/R) injury is experienced by individuals suffering from cardiovascular diseases such as coronary heart diseases and subsequently undergoing reperfusion treatments in order to manage the conditions. The occlusion of blood flow to the tissue, termed ischemia, can be especially detrimental to the heart due to its high energy demand. Several cellular alterations have been observed upon the onset of ischemia. The danger created by cardiac ischemia is somewhat paradoxical in that a return of blood to the tissue can result in further damage. Reactive oxygen species (ROS) have been studied intensively to reveal their role in myocardial I/R injury. Under normal conditions, ROS function as a mediator in many cell signaling pathways. However, stressful environments significantly induce the generation of ROS which causes the level to exceed body’s antioxidant defense system. Such altered redox homeostasis is implicated in myocardial I/R injury. Despite the detrimental effects from ROS, low levels of ROS have been shown to exert a protective effect in the ischemic preconditioning. In this review, we will summarize the detrimental role of ROS in myocardial I/R injury, the protective mechanism induced by ROS, and potential treatments for ROS-related myocardial injury.

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PGC-1α, Inflammation, and Oxidative Stress: An Integrative View in Metabolism

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/1452696 ◽

2020 ◽

Vol 2020 ◽

pp. 1-20 ◽

Cited By ~ 21

Author(s):

Sergio Rius-Pérez ◽

Isabel Torres-Cuevas ◽

Iván Millán ◽

Ángel L. Ortega ◽

Salvador Pérez

Keyword(s):

Oxidative Stress ◽

Reactive Oxygen Species ◽

Metabolic Syndrome ◽

Inflammatory Response ◽

Reactive Oxygen ◽

High Energy ◽

Low Grade ◽

Oxygen Species ◽

Antioxidant Genes ◽

Integrative View

Peroxisome proliferator-activated receptor-γ coactivator (PGC)-1α is a transcriptional coactivator described as a master regulator of mitochondrial biogenesis and function, including oxidative phosphorylation and reactive oxygen species detoxification. PGC-1α is highly expressed in tissues with high energy demands, and it is clearly associated with the pathogenesis of metabolic syndrome and its principal complications including obesity, type 2 diabetes mellitus, cardiovascular disease, and hepatic steatosis. We herein review the molecular pathways regulated by PGC-1α, which connect oxidative stress and mitochondrial metabolism with inflammatory response and metabolic syndrome. PGC-1α regulates the expression of mitochondrial antioxidant genes, including manganese superoxide dismutase, catalase, peroxiredoxin 3 and 5, uncoupling protein 2, thioredoxin 2, and thioredoxin reductase and thus prevents oxidative injury and mitochondrial dysfunction. Dysregulation of PGC-1α alters redox homeostasis in cells and exacerbates inflammatory response, which is commonly accompanied by metabolic disturbances. During inflammation, low levels of PGC-1α downregulate mitochondrial antioxidant gene expression, induce oxidative stress, and promote nuclear factor kappa B activation. In metabolic syndrome, which is characterized by a chronic low grade of inflammation, PGC-1α dysregulation modifies the metabolic properties of tissues by altering mitochondrial function and promoting reactive oxygen species accumulation. In conclusion, PGC-1α acts as an essential node connecting metabolic regulation, redox control, and inflammatory pathways, and it is an interesting therapeutic target that may have significant benefits for a number of metabolic diseases.

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Interaction between reactive oxygen species and Coenzyme Q10 in an aprotic medium: A cyclic voltammetry study

Molecular Aspects of Medicine ◽

10.1016/0098-2997(94)90016-7 ◽

1994 ◽

Vol 15 ◽

pp. s83-s88 ◽

Cited By ~ 11

Author(s):

E. Ferri ◽

E. Gattavecchia ◽

G. Feroci ◽

M. Battino

Keyword(s):

Reactive Oxygen Species ◽

Cyclic Voltammetry ◽

Coenzyme Q10 ◽

Reactive Oxygen ◽

Oxygen Species ◽

Aprotic Medium

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Bacteria Coated by Polyphenols Acquire Potent Oxidant-Scavenging Capacities

Experimental Biology and Medicine ◽

10.3181/0901-rm-22 ◽

2009 ◽

Vol 234 (8) ◽

pp. 940-951 ◽

Cited By ~ 16

Author(s):

Erez Koren ◽

Ron Kohen ◽

Haim Ovadia ◽

Isaac Ginsburg

Keyword(s):

Reactive Oxygen Species ◽

Cyclic Voltammetry ◽

Lactic Acid ◽

Mammalian Cells ◽

Intestinal Tract ◽

Fruits And Vegetables ◽

Oxygen Species ◽

Probiotic Lactic Acid Bacteria ◽

Gastro Intestinal Tract ◽

Cationic Polyelectrolytes

Several microbial species, including probiotic lactic acid bacteria, have the ability to irreversibly bind a large variety of polyphenols (flavonoids) and anthocyanidins found in many colored fruits and vegetables and to enhance their total oxidant-scavenging capacities (TOSC). The binding of flavonoids to microbial surfaces was further increased by the cationic polyelectrolytes ligands poly-L-histidine, chlorhexidine and Copaxone®. This phenomenon was confirmed visually, by the FRAP, DPPH, cyclic voltammetry, Folin-Ciocalteu as well as by luminol-dependent chemiluminescence techniques employed to assay TOSC. The possibility is considered that clinically, microbial cells in the oral cavity and in the gastro intestinal tract, complexed with antioxidant polyphenols from nutrients and with cationic ligands, might increase the protection of mammalian cells against damage induced by excessive generation of reactive oxygen species during infections and inflammation.

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Comparing Early Eukaryotic Integration of Mitochondria and Chloroplasts in the Light of Internal ROS Challenges: Timing is of the Essence

mBio ◽

10.1128/mbio.00955-20 ◽

2020 ◽

Vol 11 (3) ◽

Cited By ~ 1

Author(s):

Dave Speijer ◽

Michael Hammond ◽

Julius Lukeš

Keyword(s):

Reactive Oxygen Species ◽

Driving Forces ◽

Reactive Oxygen ◽

High Energy ◽

Oxygen Species ◽

Mitochondrial Ros ◽

Transport Chain ◽

Evolutionary Trajectories ◽

Ros Formation

ABSTRACT When trying to reconstruct the evolutionary trajectories during early eukaryogenesis, one is struck by clear differences in the developments of two organelles of endosymbiotic origin: the mitochondrion and the chloroplast. From a symbiogenic perspective, eukaryotic development can be interpreted as a process in which many of the defining eukaryotic characteristics arose as a result of mutual adaptions of both prokaryotes (an archaeon and a bacterium) involved. This implies that many steps during the bacterium-to-mitochondrion transition trajectory occurred in an intense period of dramatic and rapid changes. In contrast, the subsequent cyanobacterium-to-chloroplast development in a specific eukaryotic subgroup, leading to the photosynthetic lineages, occurred in a full-fledged eukaryote. The commonalities and differences in the two trajectories shed an interesting light on early, and ongoing, eukaryotic evolutionary driving forces, especially endogenous reactive oxygen species (ROS) formation. Differences between organellar ribosomes, changes to the electron transport chain (ETC) components, and mitochondrial codon reassignments in nonplant mitochondria can be understood when mitochondrial ROS formation, e.g., during high energy consumption in heterotrophs, is taken into account. IMPORTANCE The early eukaryotic evolution was deeply influenced by the acquisition of two endosymbiotic organelles - the mitochondrion and the chloroplast. Here we discuss the possibly important role of reactive oxygen species in these processes.

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Mechanism of the Formation of Electronically Excited Species by Oxidative Metabolic Processes: Role of Reactive Oxygen Species

Biomolecules ◽

10.3390/biom9070258 ◽

2019 ◽

Vol 9 (7) ◽

pp. 258 ◽

Cited By ~ 17

Author(s):

Pavel Pospíšil ◽

Ankush Prasad ◽

Marek Rác

Keyword(s):

Reactive Oxygen Species ◽

Molecular Oxygen ◽

Reactive Oxygen ◽

High Energy ◽

Oxygen Species ◽

Human Beings ◽

Metabolic Processes ◽

Excited Species ◽

Electronically Excited

It is well known that biological systems, such as microorganisms, plants, and animals, including human beings, form spontaneous electronically excited species through oxidative metabolic processes. Though the mechanism responsible for the formation of electronically excited species is still not clearly understood, several lines of evidence suggest that reactive oxygen species (ROS) are involved in the formation of electronically excited species. This review attempts to describe the role of ROS in the formation of electronically excited species during oxidative metabolic processes. Briefly, the oxidation of biomolecules, such as lipids, proteins, and nucleic acids by ROS initiates a cascade of reactions that leads to the formation of triplet excited carbonyls formed by the decomposition of cyclic (1,2-dioxetane) and linear (tetroxide) high-energy intermediates. When chromophores are in proximity to triplet excited carbonyls, the triplet-singlet and triplet-triplet energy transfers from triplet excited carbonyls to chromophores result in the formation of singlet and triplet excited chromophores, respectively. Alternatively, when molecular oxygen is present, the triplet-singlet energy transfer from triplet excited carbonyls to molecular oxygen initiates the formation of singlet oxygen. Understanding the mechanism of the formation of electronically excited species allows us to use electronically excited species as a marker for oxidative metabolic processes in cells.

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Sensors Based on Metal Nanoclusters Stabilized on Designed Proteins

Biosensors ◽

10.3390/bios8040110 ◽

2018 ◽

Vol 8 (4) ◽

pp. 110 ◽

Cited By ~ 2

Author(s):

Antonio Aires ◽

Elena Lopez-Martinez ◽

Aitziber Cortajarena

Keyword(s):

Reactive Oxygen Species ◽

Optical Properties ◽

Metal Ions ◽

Temperature Sensors ◽

Oxygen Species ◽

Protein Scaffolds ◽

Metal Nanoclusters ◽

Designed Proteins ◽

New Sensors ◽

Potential Use

Among all new nanomaterials, metal nanoclusters (NCs) have attracted special attention due to their interesting optical properties, among others. Metal NCs have been recently studied and used as sensors for different analytes. However, there is a need to explore the potential of these new sensors in a systematic manner and to develop new systems to broaden the possibilities that sensing offers to the industry. In this work, we show the potential use of repeat protein scaffolds as versatile templates for the synthesis and stabilization of various metal NCs, specifically Au, Ag, and CuNCs. The resulting protein-metal NCs hybrids are evaluated as sensors for different stimuli such as temperature, ions, or reactive oxygen species (ROS). Among the three protein-metal NCs, all performed nicely as temperature sensors, AuNCs responded to metal ions, and AgNCs were able to detect ROS.

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