Radical-free biology of oxidative stress

Free radical-induced macromolecular damage has been studied extensively as a mechanism of oxidative stress, but large-scale intervention trials with free radical scavenging antioxidant supplements show little benefit in humans. The present review summarizes data supporting a complementary hypothesis for oxidative stress in disease that can occur without free radicals. This hypothesis, which is termed the “redox hypothesis,” is that oxidative stress occurs as a consequence of disruption of thiol redox circuits, which normally function in cell signaling and physiological regulation. The redox states of thiol systems are sensitive to two-electron oxidants and controlled by the thioredoxins (Trx), glutathione (GSH), and cysteine (Cys). Trx and GSH systems are maintained under stable, but nonequilibrium conditions, due to a continuous oxidation of cell thiols at a rate of about 0.5% of the total thiol pool per minute. Redox-sensitive thiols are critical for signal transduction (e.g., H-Ras, PTP-1B), transcription factor binding to DNA (e.g., Nrf-2, nuclear factor-κB), receptor activation (e.g., αIIbβ3 integrin in platelet activation), and other processes. Nonradical oxidants, including peroxides, aldehydes, quinones, and epoxides, are generated enzymatically from both endogenous and exogenous precursors and do not require free radicals as intermediates to oxidize or modify these thiols. Because of the nonequilibrium conditions in the thiol pathways, aberrant generation of nonradical oxidants at rates comparable to normal oxidation may be sufficient to disrupt function. Considerable opportunity exists to elucidate specific thiol control pathways and develop interventional strategies to restore normal redox control and protect against oxidative stress in aging and age-related disease.

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Oxidative Stress, Mitochondrial DNA Mutation, and Impairment of Antioxidant Enzymes in Aging

Experimental Biology and Medicine ◽

10.1177/153537020222700901 ◽

2002 ◽

Vol 227 (9) ◽

pp. 671-682 ◽

Cited By ~ 377

Author(s):

Yau-Huei Wei ◽

Hsin-Chen Lee

Keyword(s):

Oxidative Stress ◽

Mitochondrial Dna ◽

Antioxidant Enzymes ◽

Oxidative Damage ◽

Large Scale ◽

Wide Spectrum ◽

Radical Scavenging ◽

Mtdna Mutations ◽

Enhanced Production ◽

Age Related

Mitochondria do not only produce less ATP, but they also increase the production of reactive oxygen species (ROS) as byproducts of aerobic metabolism in the aging tissues of the human and animals. It is now generally accepted that aging-associated respiratory function decline can result in enhanced production of ROS in mitochondria. Moreover, the activities of free radical-scavenging enzymes are altered in the aging process. The concurrent age-related changes of these two systems result in the elevation of oxidative stress in aging tissues. Within a certain concentration range, ROS may induce stress response of the cells by altering expression of respiratory genes to uphold the energy metabolism to rescue the cell. However, beyond the threshold, ROS may cause a wide spectrum of oxidative damage to various cellular components to result in cell death or elicit apoptosis by induction of mitochondrial membrane permeability transition and release of apoptogenic factors such as cytochrome c. Moreover, oxidative damage and large-scale deletion and duplication of mitochondrial DNA (mtDNA) have been found to increase with age in various tissues of the human. Mitochondria act like a biosensor of oxidative stress and they enable cell to undergo changes in aging and age-related diseases. On the other hand, it has recently been demonstrated that impairment in mitochondrial respiration and oxidative phosphorylation elicits an increase in oxidative stress and causes a host of mtDNA rearrangements and deletions. Here, we review work done in the past few years to support our view that oxidative stress and oxidative damage are a result of concurrent accumulation of mtDNA mutations and defective antioxidant enzymes in human aging.

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Free Radical Scavenging potential of different extracts of Tabebuia roseo-alba (Ridl) Sand leaves

Research Journal of Pharmacy and Technology ◽

10.52711/0974-360x.2021.00835 ◽

2021 ◽

pp. 4801-4807

Author(s):

Suseela V. ◽

Sushmita L. ◽

Bharatkumar R. ◽

Nirmaladevi R.

Keyword(s):

Oxidative Stress ◽

Free Radical ◽

Radical Scavenging ◽

Reducing Power ◽

Ethanolic Extract ◽

Free Radical Scavenging ◽

Age Related ◽

Radical Scavenging Properties ◽

Hydroxyl Hydrogen

The present study was carried out to elucidate the in vitro free radical scavenging potential of various extracts of Tabebuia roseo-alba leaves. Assays for radical scavenging, such as DPPH, ABTS+, hydroxyl, hydrogen peroxide, superoxide, nitric oxide assay and reducing power activity were performed using standard protocols and the results were compared with standard ascorbic acid. Among the various extracts used the ethanolic extract of T. roseo-alba exhibited efficient scavenging potential with lowest EC50 value proving its antioxidant potential. Leaves of T. roseo-alba have strong free radical scavenging properties and thus can be used as a potential antioxidant to resolve diseases that are associated with oxidative stress including diabetes and other age related disorders.

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Study of antioxidant potential in leaves, stems, nuts of Juglans regia L.

International Journal of Bioassays ◽

10.21746/ijbio.2012.10.003 ◽

2012 ◽

Vol 1 (10) ◽

pp. 79 ◽

Cited By ~ 2

Author(s):

G. Raja* ◽

Ivvala Anand Shaker ◽

Inampudi Sailaja ◽

R. Swaminathan ◽

S. Saleem Basha ◽

...

Keyword(s):

Free Radicals ◽

Free Radical ◽

Antioxidant Activities ◽

Radical Scavenging Activity ◽

Juglans Regia ◽

Radical Scavenging ◽

Antioxidant Compounds ◽

Free Radical Damage ◽

Radical Damage

Natural antioxidants can protect the human body from free radicals and retard the progress of many chronic diseases as well as lipid oxidative rancidity in foods. The role of antioxidants has protected effect against free radical damage that may cause many diseases including cancer. Primary sources of naturally occurring antioxidants are known as whole grains, fruits, and vegetables. Several studies suggest that regular consumption of nuts, mostly walnuts, may have beneficial effects against oxidative stress mediated diseases such as cardiovascular disease and cancer. The role of antioxidants has attracted much interest with respect to their protective effect against free radical damage that may cause many diseases including cancer. Juglans regia L. (walnut) contains antioxidant compounds, which are thought to contribute to their biological properties. Polyphenols, flavonoids and flavonols concentrations and antioxidant activity of Leaves, Stems and Nuts extract of Juglans regia L. as evaluated using DPPH, ABTS, Nitric acid, hydroxyl and superoxide radical scavenging activity, lipid peroxidation and total oxidation activity were determined. The antioxidant activities of Leaves, Stems and Nuts extract of Juglans regia L. were concentration dependent in different experimental models and it was observed that free radicals were scavenged by the test compounds in all the models.

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Development of a free radical scavenging bacterial consortium to mitigate oxidative stress in cnidarians

Microbial Biotechnology ◽

10.1111/1751-7915.13877 ◽

2021 ◽

Author(s):

Ashley M. Dungan ◽

Dieter Bulach ◽

Heyu Lin ◽

Madeleine J. H. van Oppen ◽

Linda L. Blackall

Keyword(s):

Oxidative Stress ◽

Free Radical ◽

Radical Scavenging ◽

Bacterial Consortium ◽

Free Radical Scavenging

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In Vitro and In Vivo Antioxidant Properties of Taraxacum officinale in Nω-Nitro-l-Arginine Methyl Ester (L-NAME)-Induced Hypertensive Rats

Antioxidants ◽

10.3390/antiox8080309 ◽

2019 ◽

Vol 8 (8) ◽

pp. 309

Author(s):

Olukayode O. Aremu ◽

Adebola O. Oyedeji ◽

Opeoluwa O. Oyedeji ◽

Benedicta N. Nkeh-Chungag ◽

Constance R. Sewani Rusike

Keyword(s):

Oxidative Stress ◽

Free Radical ◽

Methyl Ester ◽

Leaf Extract ◽

Radical Scavenging ◽

Free Radical Scavenging ◽

Hypertensive Rats ◽

Total Antioxidant

Oxidative stress has gained attention as one of the fundamental mechanisms responsible for the development of hypertension. The present study investigated in vitro and in vivo antioxidant effects of 70% ethanol-water (v/v) leaf and root extracts of T. officinale (TOL and TOR, respectively). Total phenolic and flavonoid content of plant extracts were assessed using Folin Ciocalteau and aluminium chloride colorimetric methods; while, 2,2-diphenyl-1-picrlhydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and ferric reducing antioxidant power (FRAP) protocols were used to determine the free radical scavenging and total antioxidant capacities (TAC), respectively. The in vivo total antioxidant capacity and malondialdehyde acid (MDA) levels for lipid peroxidation tests were performed on organ homogenate samples from Nω-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats treated with leaf extract, TOL (500 mg/kg/day) and TOR (500 mg/kg/day) for 21 days. Results showed that compared to TOR, TOL possessed significantly higher (p < 0.01) polyphenol (4.35 ± 0.15 compared to 1.14 ± 0.01) and flavonoid (23.17 ± 0.14 compared to 3 ± 0.05) content; free radical scavenging activity (EC50 0.37 compared to 1.34 mg/mL) and total antioxidant capacities (82.56% compared to 61.54% ABTS, and 156 ± 5.28 compared to 40 ± 0.31 FRAP) and both extracts showed no toxicity (LD50 > 5000 mg/kg). TOL and TOR significantly (p < 0.01) elevated TAC and reduced MDA levels in targets organs. In conclusion, T. officinale leaf extract possesses significant anti-oxidant effects which conferred significant in vivo antioxidant protection against free radical-mediated oxidative stress in L-NAME-induced hypertensive rats.

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Effects of Malaysian Tualang honey supplementation on glycemia, free radical scavenging enzymes and markers of oxidative stress in kidneys of normal and streptozotocin-induced diabetic rats

International Journal of Cardiology ◽

10.1016/j.ijcard.2009.09.148 ◽

2009 ◽

Vol 137 ◽

pp. S45 ◽

Cited By ~ 4

Author(s):

O.O. EREJUWA ◽

S.A. SULAIMAN ◽

M.S. AB WAHAB ◽

K.N.S. SIRAJUDEEN ◽

M.S. SALZIHAN

Keyword(s):

Oxidative Stress ◽

Free Radical ◽

Radical Scavenging ◽

Diabetic Rats ◽

Free Radical Scavenging ◽

Markers Of Oxidative Stress ◽

Scavenging Enzymes ◽

Tualang Honey

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Mechanistic Insight into Antimicrobial and Antioxidant Potential of Jasminum Species: A Herbal Approach for Disease Management

Plants ◽

10.3390/plants10061089 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1089

Author(s):

Acharya Balkrishna ◽

Akansha Rohela ◽

Abhishek Kumar ◽

Ashwani Kumar ◽

Vedpriya Arya ◽

...

Keyword(s):

Oxidative Stress ◽

Drug Resistance ◽

Free Radicals ◽

Free Radical ◽

Microbial Pathogens ◽

Free Radical Scavengers ◽

Bioactive Constituents ◽

Global Issues ◽

Iridoid Glucosides ◽

Insight Into

Drug resistance among microbial pathogens and oxidative stress caused by reactive oxygen species are two of the most challenging global issues. Firstly, drug-resistant pathogens cause several fatalities every year. Secondly aging and a variety of diseases, such as cardiovascular disease and cancer, are associated with free radical generated oxidative stress. The treatments currently available are limited, ineffective, or less efficient, so there is an immediate need to tackle these issues by looking for new therapies to resolve resistance and neutralize the harmful effects of free radicals. In the 21st century, the best way to save humans from them could be by using plants as well as their bioactive constituents. In this specific context, Jasminum is a major plant genus that is used in the Ayurvedic system of medicine to treat a variety of ailments. The information in this review was gathered from a variety of sources, including books, websites, and databases such as Science Direct, PubMed, and Google Scholar. In this review, a total of 14 species of Jasminum have been found to be efficient and effective against a wide variety of microbial pathogens. In addition, 14 species were found to be active free radical scavengers. The review is also focused on the disorders related to oxidative stress, and it was concluded that Jasminum grandiflorum and J. sambac normalized various parameters that were elevated by free radical generation. Alkaloids, flavonoids (rutoside), terpenes, phenols, and iridoid glucosides are among the main phytoconstituents found in various Jasminum species. Furthermore, this review also provides insight into the mechanistic basis of drug resistance, the generation of free radicals, and the role of Jasminum plants in combating resistance and neutralizing free radicals.

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Ethanol Extract of Maclura tricuspidata Fruit Protects SH-SY5Y Neuroblastoma Cells against H2O2-Induced Oxidative Damage via Inhibiting MAPK and NF-κB Signaling

International Journal of Molecular Sciences ◽

10.3390/ijms22136946 ◽

2021 ◽

Vol 22 (13) ◽

pp. 6946

Author(s):

Weishun Tian ◽

Suyoung Heo ◽

Dae-Woon Kim ◽

In-Shik Kim ◽

Dongchoon Ahn ◽

...

Keyword(s):

Oxidative Stress ◽

Free Radical ◽

Oxidative Damage ◽

Cell Damage ◽

Antioxidant Properties ◽

Radical Scavenging ◽

Biologically Active ◽

Mitogen Activated Protein Kinase ◽

Protective Effects ◽

Neuroprotective Effects

Free radical generation and oxidative stress push forward an immense influence on the pathogenesis of neurodegenerative diseases such as Alzheimer’s disease and Parkinson’s disease. Maclura tricuspidata fruit (MT) contains many biologically active substances, including compounds with antioxidant properties. The current study aimed to investigate the neuroprotective effects of MT fruit on hydrogen peroxide (H2O2)-induced neurotoxicity in SH-SY5Y cells. SH-SY5Y cells were pretreated with MT, and cell damage was induced by H2O2. First, the chemical composition and free radical scavenging properties of MT were analyzed. MT attenuated oxidative stress-induced damage in cells based on the assessment of cell viability. The H2O2-induced toxicity caused by ROS production and lactate dehydrogenase (LDH) release was ameliorated by MT pretreatment. MT also promoted an increase in the expression of genes encoding the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT). MT pretreatment was associated with an increase in the expression of neuronal genes downregulated by H2O2. Mechanistically, MT dramatically suppressed H2O2-induced Bcl-2 downregulation, Bax upregulation, apoptotic factor caspase-3 activation, Mitogen-activated protein kinase (MAPK) (JNK, ERK, and p38), and Nuclear factor-κB (NF-κB) activation, thereby preventing H2O2-induced neurotoxicity. These results indicate that MT has protective effects against H2O2-induced oxidative damage in SH-SY5Y cells and can be used to prevent and protect against neurodegeneration.

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8. Evaluation of Snow Fungus Polysaccharides on benzo[a]pyrene-induced DNA Damage

Inquiry@Queen's Undergraduate Research Conference Proceedings ◽

10.24908/iqurcp.10074 ◽

2018 ◽

Author(s):

Daisy Liu

Keyword(s):

Oxidative Stress ◽

Dna Damage ◽

Free Radical ◽

Radical Scavenging ◽

Chinese Hamster ◽

Negative Control ◽

Lung Fibroblasts ◽

Protective Effects ◽

Tremella Fuciformis

Snow fungus, Tremella fuciformis, has been demonstrated to have numerous health benefits including purported chemopreventive properties due to free radical-scavenging ability. Protective effects derived from snow fungus polysaccharides are evaluated on Chinese hamster lung fibroblasts (CCL-39) exposed to carcinogen benzo[a]pyrene known to cause free radical formation and oxidative stress to cells. In this experiment, it was hypothesized that the naturally occurring polysaccharides in snow fungus are able to protect against or reduce oxidative stress-induced DNA damage. Polysaccharides were isolated through an alkaline extraction and in-vitro digestion. DNA damage was measured using the single-cell gel electrophoresis comet assay after exposure to benzo[a]pyrene and polysaccharide extract to lung fibroblasts. Results were calculated using the mean and standard deviation data of tail length and area, respectively. Each damaged cell was measured and analyzed through ImageJ Editing Software. The results indicate a promising trend which depict snow fungus polysaccharides yielding lower levels of DNA damage compared to cells exposed to benzo[a]pyrene and compared to the negative control (phosphate buffered saline and Dulbecco’s cell medium). This study suggests polysaccharides from Tremella fuciformis could truly prevent cellular DNA damage by protecting against oxidative stress.

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