Different Types Of Antioxidants Research Articles

Use of antioxidants to retard aging of bitumen: A review.

Oxidative aging of bitumen is an inevitable and irreversible phenomenon. Exposure to detrimental factors such as sunlight, oxygen, and UV radiations accelerates the aging of bitumen and bituminous pavement. The aging process induces hardening and embrittlement in bitumen, leading to premature pavement failure. Therefore, for constructing sustainable long-lasting pavements anti-aging additives are used. Among the available additives, the use of antioxidants has emerged as a promising solution to mitigate the aging of bitumen. The current review aims to summarise the existing literature for a comprehensive understanding of the effectiveness of these additives as aging inhibitors. It provides an overview of the chemical pathway involved during bitumen oxidation and various quantification techniques to measure the effect of aging. This review also highlights the potential use of antioxidants in bitumen and elaborates on the working mechanism of different types of antioxidants to prevent bitumen aging. Further, the effect of modification in bitumen at micro, macro, and mixture levels are discussed. Additionally, cost analysis and future prospects on the use of antioxidants for bitumen are presented.

Selection of antioxidants for capacitor grade polypropylene film: Insights into electrical performance of the oil-film system.

High voltage power capacitors employ the oil-impregnated polypropylene film as the insulation. The swelling phenomenon might drive the antioxidants and small molecules within the film to migrate into the oil. It is necessary to comprehensively investigate the physical migration mechanism of antioxidants and their impact on the electrical performance of the oil-film combination insulation system and, consequently, formulate the proper selective prescription of antioxidants. Theoretical elucidation of the competitive interaction mechanism between the film and the oil in attracting antioxidant molecules was achieved through the calculation of inter-molecular binding energy, and the migration coefficient ηm was introduced to quantify the migration characteristics of antioxidants. Experimentally, the effects of antioxidants on the space charge distribution of the film, the dielectric properties of the oil, and the breakdown characteristics of both the film and oil were investigated. The experimental conclusions are consistent with theoretical analysis. The lamellar structure antioxidant molecules with ηm > 1 tend to migrate from the film to the oil, which results in increased dielectric loss and decreased breakdown strength of the insulating oil. In addition, the presence of phosphorus atoms in phosphite antioxidants contributes to a reduction in the breakdown strength of the film. For capacitor grade polypropylene film, in addition to the synergistic effect between different types of antioxidants on the thermo-oxidative stability, the structure of the antioxidant molecules and its influence on the electrical performance of the oil-film systems should also be taken into account.

A Review on Beneficial Properties of Purple Okra

Okra is one of the most popular and commercially grown vegetables in different parts of the India due its nutritive, medicinal and economic value. Generally, green tender pods of okra are used as edible purpose and green varieties are commercially cultivated for most okra growing areas even export market also dominated by green varieties despite being the higher nutritive value of purple okra or red okra than green okra. Purple okra has enormous health benefits and can be used as traditional medicine in China and Indonesia. Several epidemiological studies proof superiority of purple okra over green okra due to presence of different types of antioxidants like beta-carotene, anthocyanin and phenolic compounds. Higher nutrients’ composition of purple okra can prevent some chronic diseases like goitre, diabetes, hyperlipidaemia, microbial infections, ulcers, and neurodegenerative diseases, irritation of the stomach and colon, gonorrhoea, sore throat, dysentery and also lower blood sugar. The fruits of purple okra have beneficial properties like anti-gastric acid, anti-oxidative, anti-fatigue, anti-inflammatory and even have insecticidal properties.

Antioxidant therapy against TGF-β/SMAD pathway involved in organ fibrosis.

Fibrosis refers to excessive build-up of scar tissue and extracellular matrix components in different organs. In recent years, it has been revealed that different cytokines and chemokines, especially Transforming growth factor beta (TGF-β) is involved in the pathogenesis of fibrosis. It has been shown that TGF-β is upregulated in fibrotic tissues, and contributes to fibrosis by mediating pathways that are related to matrix preservation and fibroblasts differentiation. There is no doubt that antioxidants protect against different inflammatory conditions by reversing the effects of nitrogen, oxygen and sulfur-based reactive elements. Oxidative stress has a direct impact on chronic inflammation, and as results, prolonged inflammation ultimately results in fibrosis. Different types of antioxidants, in the forms of vitamins, natural compounds or synthetic ones, have been proven to be beneficial in the protection against fibrotic conditions both invitro and invivo. In this study, we reviewed the role of different compounds with antioxidant activity in induction or inhibition of TGF-β/SMAD signalling pathway, with regard to different fibrotic conditions such as gastro-intestinal fibrosis, cardiac fibrosis, pulmonary fibrosis, skin fibrosis, renal fibrosis and also some rare cases of fibrosis, both in animal models and cell lines.

Interaction of Thiol Antioxidants with α,β-Unsaturated Ketone Moiety: Its Implication for Stability and Bioactivity of Curcuminoids

Many biological functions of curcumin have been reported. As certain bioactivities of curcumin are eliminated by antioxidants, reactive oxygen species generated by curcumin have been suggested as a relevant mechanism. In the present study, the effects of different types of antioxidants on the stability and bioactivities of curcumin were analyzed. High concentrations (>4 mM) of thiol antioxidants, including N-acetylcysteine (NAC), glutathione (GSH), and β-mercaptoethanol, accelerated the decomposition of curcumin and other curcuminoids; the submillimolar levels (<0.5 mM) of GSH and NAC rather improved their stability. Ascorbic acid or superoxide dismutase also stabilized curcumin, regardless of their concentration. The cellular levels and bioactivities of curcumin, including its cytotoxicity and the induction of heme oxygenase-1, were significantly reduced in the presence of 8 mM of GSH and NAC. The effects were enhanced in the presence of submillilmolar GSH and NAC, or non-thiol antioxidants. The present results indicate that antioxidants with a reduced thiol group could directly interact with the α,β-unsaturated carbonyl moiety of curcuminoids and modulate their stability and bioactivity.

Antioxidative effects of vitamin D in muscle dysfunction

Graphical abstract Abstract Pathological conditions characterized by systemic inflammation and oxidative stress can often impair the muscle cells efficiency. The gradual decline of muscle mass and tone drastically reduces the motor skills of the patient affecting the simplest daily activities. Muscle dysfunction, resulting in the deterioration of muscle tissue, can lead to a serious situation of muscle wasting that can evolve into sarcopenia. In addition, muscle dysfunction causing metabolic disorders impairs the quality of life. The function of skeletal muscle is deeply conditioned by environmental, nutritional, physical, and genetic factors. Proper nutrition with balanced protein and vitamins intake and an active lifestyle helps to strengthen tissues and counteract pathological conditions and generalized weakness. Vitamin D performs antioxidant actions, indispensable in skeletal muscle. Epidemiological data indicate that vitamin D deficiency is a widespread status in the world. Vitamin D deficiency induces mitochondrial failure, reduced production of adenosine triphosphate, oxidative injury, and compromised muscle function. Among the different types of antioxidants, vitamin D has been identified as the main compound that can improve the effectiveness of the treatment for muscle weakness and improve conditions related to sarcopenia. The purpose of this review is to analyze molecular processes used by vitamin D against oxidative stress and how it can affect muscle function in order to assess whether its use as a supplement in inflammatory pathologies and oxidative stress can be useful to prevent deterioration and improve/maintain muscle function.

Research Progress of Antioxidants in Oxidative Stress Therapy after Spinal Cord Injury.

Spinal cord injury (SCI) is a serious problem in the central nervous system resulting in high disability and mortality with complex pathophysiological mechanisms. Oxidative stress is one of the main secondary reactions of SCI, and its main pathophysiological marker is the production of excess reactive oxygen species. The overproduction of reactive oxygen species and insufficient antioxidant capacity lead to the occurrence of oxidative stress and neuroinflammation, and the dysregulation of oxidative stress and neuroinflammation leads to further aggravation of damage. Oxidative stress can initiate a variety of inflammatory and apoptotic pathways, and targeted antioxidant therapy can greatly reduce oxidative stress and reduce neuroinflammation, which has a certain positive effect on rehabilitation and prognosis in SCI. This article reviewed the research on different types of antioxidants and related treatments in SCI, focusing on the mechanisms of oxidative stress.

A New Method to Determine Antioxidant Activities of Biofilms Using a pH Indicator (Resazurin) Model System

Biopolymeric films were prepared with gelatin, plasticizer, and three different types of antioxidants (ascorbic acid, phytic acid, and BHA) corresponding to different mechanisms in activity. The antioxidant activity of films was monitored for 14 storage days upon color changes using a pH indicator (resazurin). The instant antioxidant activity of films was measured by a DPPH free radical test. The system using resazurin was composed of an agar, an emulsifier, and soybean oil to simulate a highly oxidative oil-based food system (AES-R). Gelatin-based films (GBF) containing phytic acid showed higher tensile strength and energy to break than all other samples due to the increased intermolecular interactions between phytic acid and gelatin molecules. The oxygen barrier properties of GBF films containing ascorbic acid and phytic acid increased due to the increased polarity, while GBF films containing BHA showed increased oxygen permeability compared to the control. According to "a-value" (redness) of the AES-R system tested with films, films incorporating BHA showed the most retardation of lipid oxidation in the system. This retardation corresponds to 59.8% antioxidation activity at 14 days, compared with the control. Phytic acid-based films did not show antioxidant activity, whereas ascorbic acid-based GBFs accelerated the oxidation process due to its prooxidant activity. The comparison between the DPPH free radical test and the control showed that the ascorbic acid and BHA-based GBFs showed highly effective free radical scavenging behavior (71.7% and 41.7%, respectively). This novel method using a pH indicator system can potentially determine the antioxidation activity of biopolymer films and film-based samples in a food system.

Controlled Production of Carnosic Acid and Carnosol in Cell Suspensions of Lepechinia meyenii Treated with Different Elicitors and Biosynthetic Precursors.

Lepechinia meyenii is a medicinal plant specialized in the biosynthesis of different types of antioxidants including the diterpenes carnosic (CA) acid and carnosol (CS). Herein we present the results of plant tissue culture approaches performed in this medicinal plant with particular emphasis on the generation and evaluation of a cell suspension system for CA and CS production. The effect of sucrose concentration, temperature, pH, and UV-light exposure was explored. In addition, diverse concentrations of microbial elicitors (salicylic acid, pyocyanin, Glucanex, and chitin), simulators of abiotic elicitors (polyethylene glycol and NaCl), and biosynthetic precursors (mevalonolactone, geranylgeraniol, and miltiradiene/abietatriene) were evaluated on batch cultures for 20 days. Miltiradiene/abietatriene obtainment was achieved through a metabolic engineering approach using a recombinant strain of Saccharomyces cerevisiae. Our results suggested that the maximum accumulation (Accmax ) of CA and CS was mainly conferred to stimuli associated with oxidative stress such as UV-light exposure (Accmax , 6.2 mg L-1 ) polyethylene glycol (Accmax , 6.5 mg L-1 ) NaCl (Accmax , 5.9 mg L-1 ) which simulated drought and saline stress, respectively. Nevertheless the bacterial elicitor pyocyanin was also effective to increase the production of both diterpenes (Accmax , 6.4 mg L-1 ). Outstandingly, the incorporation of upstream biosynthetic precursors such as geranylgeraniol and miltiradiene/abietatriene, generated the best results with Accmax of 8.6 and 16.7 mg L-1 , respectively. Optimized batch cultures containing 100 mg L-1 geranylgeraniol, 50 mg L-1 miltiradiene/abietatriene (95 : 5 %) and 5 g L-1 polyethylene glycol treated with 6 min UV light pulse during 30 days resulted in Accmax of 26.7 mg L-1 for CA and 17.3 mg L-1 for CS on days 18-24. This strategy allowed to increase seven folds the amounts of CA and CS in comparison with batch cultures without elicitation (Accmax , 4.3 mg L-1 ).

Investigation of low heat rejection diesel engine run on N,N′‐diphenyl‐p‐phenylenediamine antioxidant doped Jatropha methyl ester‐diesel blend

AbstractLow heat rejection (LHR) diesel engines help increase engine performance and reduce engine emissions, but they increase air‐polluting nitrogen oxide (NOx) emissions. Different types of antioxidants or additives can be added to fuels to reduce NOx emissions and improve engine performance. In this investigation, N,N′‐diphenyl‐p‐phenylenediamine (DPPD) is used as an antioxidant. Different concentrations of DPPD namely, 500, 1000, 1500, and 2000 ppm are mixed with Jatropha Methyl Ester (JME)‐diesel blend (JME20), and the fuels are tested in an engine fitted with a TBC piston. The piston crown is coated using a mixture of Yttria‐stabilized zirconia (YSZ) and cerium oxide (CeO2) with a coating thickness of 0.3 mm. The novelty of this research work is the comprehensive assessment of the engine characteristics of an LHR diesel engine run on a synthetic antioxidant‐doped biodiesel‐diesel blend. Results indicate that the peak heat release rate (HRR) and the peak cylinder pressure are lesser by about 5.6% and 5.1% for JME20B4, respectively, at maximum engine load, in the coated engine (CE). The nitric oxide (NO), hydrocarbon (HC), and carbon monoxide (CO) emissions are reduced by about 6.5%, 17.4%, and 34.6%, respectively, at full load for the JME20B4 fueled LHR diesel engine. Smoke opacity decreases up to 15.3% in the coated diesel engine fueled with JME20B4 at full load.

Effect of synthetic antioxidant-doped biodiesel in the low heat rejection engine

Thermal barrier coated (TBC) engines are used to increase engine performance and reduce emissions, but they increase NOx emissions. Biofuels can be doped with different types of antioxidants or additives to reduce NOx emissions and improve engine performance. In this investigation, N-isopropyl-N′-phenyl-1, 4-phenylenediamine (IPPD) is used as an antioxidant. IPPD at different concentrations, viz. 500, 1000, 1500 and 2000 ppm, was mixed with Jatropha methyl ester (JME) and the mixtures were tested as fuels in a TBC piston assembled engine. The piston crown is coated with a mixture of yttria-stabilized zirconia (YSZ) and cerium oxide (CeO2) with a thickness of 0.3 mm. The TBC piston is assembled in a single-cylinder, four-stroke, naturally aspirated, direct injection (DI), constant speed diesel engine for the investigation. The brake thermal efficiency (BTE) is higher by 18.8% than that of the conventional engine, and the brake-specific fuel consumption (BSFC) is lower by 11.7%. Unburnt hydrocarbon (HC), carbon monoxide (CO) and smoke emissions are lower by about 23.4%, 22.9% and 23.5%, respectively, at maximum load, after doping with the antioxidant compared with the JME-fueled conventional engine. Nitric oxide (NO) emission was reduced by 8.9% at maximum load for JME doped with 1000 ppm antioxidant.

Evaluation of distinct modes of oxidative secondary injury generated in heat-treated cells of Escherichia coli with solid/liquid and complex/semi-synthetic media sets.

To characterize and evaluate oxidative secondary injury generated in heat-treated Escherichia coli cells during recovery cultivation either on agar or in a broth of a semi-synthetic enriched M9 (EM9) medium and a complex Luria broth (LB) medium with different types of antioxidants. E. coli cells grown in the EM9 and LB broth were heated at 50°C in a buffer (pH7.0). Heated cells were recovered on the same kind of agar medium as that used for growth, with or without different antioxidants. Although these antioxidants mostly protected the cells from oxidative secondary injury on the recovery media, sodium thiosulphate and sodium pyruvate were most protective on EM9 and LB agars, respectively. Determination of viability using the most probable number and growth delay analysis methods showed significant reductions in the protective effects of antioxidants in the EM9 and LB media. Oxidative secondary injury generated in heated E. coli cells was found to be qualitatively and quantitatively diverse under cellular and environmental conditions. Our results suggest that different modes of oxidation should be considered in viability determination and injured cell enumeration of heat-treated cells.

The Pathogenic Role of Foam Cells in Atherogenesis: Do They Represent Novel Therapeutic Targets?

Foam cells, mainly derived from monocytes-macrophages, contain lipid droplets essentially composed of cholesterol in their cytoplasm. They infiltrate the intima of arteries, contributing to the formation of atherosclerotic plaques. Foam cells damage the arterial cell wall via the release of proinflammatory cytokines, free radicals, and matrix metalloproteinases, enhancing the plaque size up to its rupture. A correct dietary regimen seems to be the most appropriate therapeutic approach to minimize obesity, which is associated with the formation of foam cells. At the same time, different types of antioxidants have been evaluated to arrest the formation of foam cells, even if the results are still contradictory. In any case, a combination of antioxidants seems to be more efficient in the prevention of atherosclerosis.

OXIDATIVE STRESS AND ANTIOXIDANTS WITH EMPHASIS ON AGEING (Review Article)

Numerous theories have been postulated to understand the process of aging. One of them links degenerative senescence to reactive oxygen species (ROS), which are natural byproducts of oxygen metabolism. Understanding and supporting this theory may be of great importance due to number of reasons. Firstly, there are well-established risk factors that can increase the production of ROS in our body. Secondly, there are different types of antioxidants that can neutralize toxic effects of ROS. Examples of antioxidants include natural enzymes produced in our body, as well as certain exogenous supplements. Moreover, antioxidant supplementation is already offered by some facilities as a hope to decrease age-related complications. Therefore, it is crucial to understand, how ROS is involved in the process of aging and if there is any evidence how alteration in ROS and antioxidants levels influence the process of ageing.

The Role of Mitochondria in Oocyte Maturation

With the nucleus as an exception, mitochondria are the only animal cell organelles containing their own genetic information, called mitochondrial DNA (mtDNA). During oocyte maturation, the mtDNA copy number dramatically increases and the distribution of mitochondria changes significantly. As oocyte maturation requires a large amount of ATP for continuous transcription and translation, the availability of the right number of functional mitochondria is crucial. There is a correlation between the quality of oocytes and both the amount of mtDNA and the amount of ATP. Suboptimal conditions of in vitro maturation (IVM) might lead to changes in the mitochondrial morphology as well as alternations in the expression of genes encoding proteins associated with mitochondrial function. Dysfunctional mitochondria have a lower ability to counteract reactive oxygen species (ROS) production which leads to oxidative stress. The mitochondrial function might be improved with the application of antioxidants and significant expectations are laid on the development of new IVM systems supplemented with mitochondria-targeted reagents. Different types of antioxidants have been tested already on animal models and human rescue IVM oocytes, showing promising results. This review focuses on the recent observations on oocytes’ intracellular mitochondrial distribution and on mitochondrial genomes during their maturation, both in vivo and in vitro. Recent mitochondrial supplementation studies, aiming to improve oocyte developmental potential, are summarized.

Effect of Methanolic Extract of Caryota no on Antioxidant Levels in Drosophila melanogaster

Aims: To investigate the anti-oxidant activity of the methanolic extracts of Caryota no seeds in Drosophila melanogaster (DM).
 Study Design: Experimental design.
 Place and Duration: Sample: African Centre of Excellence for Phytomedicine Research and Development, University of Jos, Jos Plateau State Nigeria between June 2018 and February 2019. 
 Methodology: These assays were conducted by exposing 50 flies per vial to the selected concentrations (350 mg, 400 mg and 500 mg) of the extract in 5 independent replicates for seven days while control group received distilled water. The total protein content was then determined from the supernatant of the fly homogenate. The antioxidant activity and levels of GST, CAT and total thiol were then measured. The statistical difference among test groups was presumed at P < .05. 
 Results: The methanolic extract of Caryota no caused nonsignificant (P = .33) decrease in total proteins in DM below basal levels in a dose-dependent pattern. The antioxidant activity showed nonsignificant (P = .28) lowering of the GST activity in DM below control levels. The methanolic extract of CN nonsignificantly (P > .05) increased the levels of catalase (P = .36) and total thiol levels (P = .22). 
 Conclusion: It can therefore be concluded that the methanolic extract of Caryota no contains appreciable concentrations of different types of antioxidants. This may provide perspectives for the evaluation and development of effective and safe phytomedicines created from the local biodiversity.

Antioxidant Activity of nHexane Extract of Caryota no Seed Using Drosophila melanogaster Model

Aims: To investigate the anti-oxidant activity of the nhexane extracts of Caryota no seeds in D. melanogaster.
 Study Design: Experimental design.
 Place and Duration: Sample: African Centre of Excellence for Phytomedicine Research and Development, University of Jos, Jos Plateau State Nigeria between June 2018 and February 2019.
 Methodology: Total protein assays were carried out by exposing 50 flies in each vial to the following concentrations: 300 mg, 350 mg, 400 mg, 500 mg and 600 mg of nhexane extracts in 5 replicates for 7 days with daily recording of mortality. In vivo antioxidant activity study was conducted by measuring levels of Glutathione-S-Transferase (GST), catalase (CAT) and total thiol (TT) from supernatants of whole fly homogenates using a spectrophotometer at specific wavelenghts. The values were derived as part of the total protein value. The statistical difference among test groups was presumed at P <0.05. 
 Results: The nhexane extract of CN caused nonsignificant (P = .52) changes in total protein levels compared to the control. The antioxidant activity showed nonsignificant (P = .64) higher total thiol contents and GST (P = .76) activity in nhexane extract-treated flies and lower catalase (P = .30) activity was recorded in the nhexane extract-treated flies compared to the controls.
 Conclusion: It can therefore be concluded that the nhexane extract of Caryota no possess appreciable concentrations of different types of antioxidants.

Potential Adverse Effect of Ultrasound on the Electroretinogram of Retina and the Protective Role of Different Types of Antioxidants

Background: Applications of ultrasound in medicine for therapeutic purposes have been an accepted and beneficial use of ultrasonic biological effects for many years but exposure to ultrasound can generate oxidative stress. Aim: The aim of the present study is to investigate the changes in the function of the retina due to ultrasound exposure and the protecting role of vitamin C and/or β-carotene by using electroretinogram (ERG). Materials and Methods: Newzealand albino rabbits of both sexes classified into five groups. Group (I) used as control group. The eyes of group (II) Insonificated with continuous ultrasound waves (1.5 W/cm2 at 2.8 MHz) for 20, 40 and 60 minutes. Group (III) was insonificated with vitamin C instillation and group (IV) insonificated after -carotene supplementation. Group (V) was insonificated after combination of the two treatments. Results: Statistically significant reduction (P˂ 0.05) in a- waves amplitude after insonification and exceeding with increase exposure time 20, 40 and 60 min was observed. The amplitudes of a-wave after treatment with topical and supplemented or both remained significantly larger compared with those exposure to US only but its latency lower than that found in insonified groups. In addition, the b-waves were found to follow the same behavior as a-wave. Conclusion: The study recommended considering oral β-carotene antioxidant in combination with vitamin C eye drops as a medical tool and personal protective in ultrasound equipment in provide safety.

SH-SY5Y Nöroblastom Hücrelerinde Beta-karoten, Alfa-tokoferol ve Askorbik asidin Antikanser Etkilerinin Araştırılması

Neuroblastoma (NB; SH-SY5Y cells) is important characteristic of the most widespread cancer in children after leukaemia and brain cancer. Discovery of new treatment approaches are required for NB disease. Epidemiological studies have demonstrated that different types of antioxidants are associated with decreased cancer and neurodegenerative diseases. Fruits and vegetables have a plenty source of Beta-carotene (BC), Alpha-tocopherol (vit E) and Ascorbic acid (vit C) that have potent free radicals scavenging actions and inhibitory properties to biochemical oxidation. BC, vit E and vit C increase the intracellular reactive oxygen species (ROS) generation and encourages cell apoptosis. It was found that these antioxidants resulted in an increase in the malondialdehyde (MDA) (marker of lipid peroxidation; LPO) and ROS levels at high concentration suggesting it behaves as a prooxidant in this study. The outcomes obviously indicated that studies of SH-SY5Y with dose-dependent BC, vit E and vit C results in oxidative damage through an increase in ROS and LPO generation and the expression of apoptotic marker caspase-3. These consequences find out additional evidences that these antioxidants could be involved in the process of apoptosis for new therapy in NB cells.

Influence of different types of antioxidants on the aging behavior of carbon-black filled NR and SBR vulcanizates

Abstract Background of this work were results of former investigations of carbon-black filled SBR and NR materials [1]. These results showed clear differences in the degradation behaviour of the used antioxidant during an artificial weathering of the vulcanizates based on SBR and NR. Further, changing material properties were observed with increasing aging time, but this could not be attributed to a decomposition process of the polymer network. For this reason, three different antioxidants IPPD, 6PPD and TMQ were selected for further investigations that are reported in this article. Different tests were performed, starting from vulcameter test over characterization of mechanical properties to viscoelastic properties. It was found that the type of antioxidant influences the material behaviour. But, a uniform grading of the antioxidants is not possible.