Antioxidant Properties of Carbon Black in Unsaturated Elastomers. Studies with cis-Polybutadiene

Abstract The thermal antioxidant behavior of carbon black was studied in vulcanized cis-polybutadiene and related to the surface chemistry of the black. Continuous and intermittent stress relaxation and oxygen absorption measurements were employed to determine the antioxidant ability of the carbon blacks. The blacks were characterized by the surface concentrations of oxygen-containing functional groups, using methods described in the literature. Antioxidant activity was found to be highest in carbons containing relatively large amounts of bound oxygen. These carbons are also acidic and decompose peroxides by the ionic mechanism. This was demonstrated with cumyl peroxide. However, even though the acidity and ability to decompose cumyl peroxide to phenol and acetone could be destroyed by methylation, this treatment did not seriously impair the antioxidant activity, so that the role of acidic groups appears to be minor. Evidence is presented which suggests strongly that the antioxidant behavior of carbon blacks is due to surface quinones, possibly hydrogen-bonded with adjacent hydroxyl groups. Measurements made on samples vulcanized in peroxide and sulfur curing systems indicate that the antioxidant behavior of carbon black is independent of the method of vulcanization in the absence of other antioxidants. A characteristic feature of the antioxidant action of carbon blacks is their tendency to repress the oxidative crosslinking reactions, the relative amount of compensation of chain scission by crosslinking being smaller than in gum vulcanizates.

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In Vitro Study of Antioxidant Activity of Serum and Plasma Samples As Well As Glutathione Exposed to Various Exogenous Stress Factors

10.21203/rs.3.rs-630921/v1 ◽

2021 ◽

Author(s):

Małgorzata Olszowy-Tomczyk ◽

Łukasz Paprotny ◽

Agnieszka Celejewska ◽

Dorota Szewczak ◽

Dorota Wianowska

Keyword(s):

Oxidative Stress ◽

Antioxidant Activity ◽

Antioxidant Properties ◽

In Vitro Study ◽

Stress Factors ◽

Plasma Samples ◽

Serum Samples ◽

Exogenous Stress

Abstract The imbalance between the production of Reactive Oxygen Species (ROS) and their sequestration promotes the formation of so-called oxidative stress conditions which are considered crucial in the aging process and development of many human diseases. Glutathione plays an essential role in the antioxidative barricade against ROS. Its role in the detoxification process of xenobiotics and carcinogen is also known. However, there are no comparative studies on the antioxidant properties of both biological samples and glutathione as well as the change in these properties as a result of exposure to various stress factors. This paper fills this gap comparing the antioxidant activity of serum and plasma samples of the known glutathione content with the activity of glutathione itself assessed by the different methods. In addition, it reveals a significant role of environmental xenobiotics in oxidative stress and differentiates the stress induced by different groups of drugs, among which the greatest one has been demonstrated for antiarrhythmic drugs and cytostatics. More importantly, it proves that human plasma is more resistant to stress factors and N-acetylcysteine clearly promotes the extension of antioxidant properties of both the plasma and serum samples. The latter conclusion is consistent with the implied preventive and/or supportive action of this drug against SARS-CoV-2.

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Synthesis and Evaluation of Antioxidant Properties of 2-Substituted Quinazolin-4(3H)-ones

Molecules ◽

10.3390/molecules26216585 ◽

2021 ◽

Vol 26 (21) ◽

pp. 6585

Author(s):

Janez Mravljak ◽

Lara Slavec ◽

Martina Hrast ◽

Matej Sova

Keyword(s):

Antioxidant Activity ◽

Phenyl Ring ◽

Biological Activities ◽

Antioxidant Properties ◽

Hydroxyl Group ◽

Hydroxyl Groups ◽

Ortho Position ◽

Dpph Assay ◽

Metal Chelating ◽

Methoxy Substituent

Quinazolinones represent an important scaffold in medicinal chemistry with diverse biological activities. Here, two series of 2-substituted quinazolin-4(3H)-ones were synthesized and evaluated for their antioxidant properties using three different methods, namely DPPH, ABTS and TEACCUPRAC, to obtain key information about the structure–antioxidant activity relationships of a diverse set of substituents at position 2 of the main quinazolinone scaffold. Regarding the antioxidant activity, ABTS and TEACCUPRAC assays were more sensitive and gave more reliable results than the DPPH assay. To obtain antioxidant activity of 2-phenylquinazolin-4(3H)-one, the presence of at least one hydroxyl group in addition to the methoxy substituent or the second hydroxyl on the phenyl ring in the ortho or para positions is required. An additional ethylene linker between quinazolinone ring and phenolic substituent, present in the second series (compounds 25a and 25b), leads to increased antioxidant activity. Furthermore, in addition to antioxidant activity, the derivatives with two hydroxyl groups in the ortho position on the phenyl ring exhibited metal-chelating properties. Our study represents a successful use of three different antioxidant activity evaluation methods to define 2-(2,3-dihydroxyphenyl)quinazolin-4(3H)-one 21e as a potent antioxidant with promising metal-chelating properties.

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The Organic Nature of Carbon Black Surfaces

Rubber Chemistry and Technology ◽

10.5254/1.3542354 ◽

1958 ◽

Vol 31 (4) ◽

pp. 941-952

Author(s):

Jules V. Hallum ◽

Harry V. Drushel

Keyword(s):

Carbon Black ◽

Functional Groups ◽

Chemical Interaction ◽

Hydroxyl Groups ◽

Carbon Blacks

Abstract Evidence is presented for the existence of quinone groups and aromatic hydroxyl groups on the surface of carbon black particles. This evidence is based largely upon polarographic analyses of slurries of carbon blacks. A mechanism for the chemical interaction of carbon blacks with elastomers is proposed on the basis of these functional groups.

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Antioxidant activity of the hazelnut plant determination by computational chemistry methods

Main Group Chemistry ◽

10.3233/mgc-200960 ◽

2021 ◽

Vol 19 (4) ◽

pp. 273-282

Author(s):

Vildan Enisoğlu Atalay ◽

İbrahim Barış Ölüç

Keyword(s):

Antioxidant Activity ◽

Free Radicals ◽

Digestive System ◽

Single Point ◽

Antioxidant Properties ◽

Hydroxyl Groups ◽

Point Energy ◽

Drinking Habits ◽

Oxidative Balance ◽

Cell Tissue

Nowadays, it is known that the species defined as free radicals in our body increase due to the change in our eating / drinking habits, physical activities and environmental conditions. Free radicals cause especially canser and diseases affecting many systems such as nervous system, cardiovascular system and digestive system. The formation of free radicals causes cell / tissue damage or cell deaths that occur as a result of oxidative balance disruption due to the insufficient antioxidants defined as oxidative stress. The purpose of this study is to determine the activity ranking of the compounds that give antioxidant properties to hazelnut plants by using quantum chemistry methods and to determine which hydroxyl groups cause the activity. In the antioxidant activity calculations, HAT, SET-PT and SPLET mechanisms are optimized with DFT//M062X/6-311++G(d,p) method, and single point energy as well as the EHOMO-ELUMO values were obtained with the Gaussian09 program in three different phases: gas, ethanol and water. According to the results, Riboflavin compound has been found to have the highest antioxidant potential and it was found that the antioxidant capacity of the compound originated from OH group at O4 position.

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Nanoencapsulated Myricetin to Improve Antioxidant Activity and Bioavailability: A Study on Zebrafish Embryos

Chemistry ◽

10.3390/chemistry4010001 ◽

2021 ◽

Vol 4 (1) ◽

pp. 1-17

Author(s):

Gopikrishna Agraharam ◽

Agnishwar Girigoswami ◽

Koyeli Girigoswami

Keyword(s):

Antioxidant Activity ◽

Fruits And Vegetables ◽

Zebrafish Embryo ◽

Antioxidant Activities ◽

Antioxidant Properties ◽

Polyphenolic Compounds ◽

Hydroxyl Groups ◽

Zebrafish Embryos ◽

Developmental Studies ◽

Positive Effects

Flavonoids are natural polyphenolic compounds that mainly possess antioxidant properties due to more hydroxyl groups in their structure and play an important role in combatting many diseases. Myricetin is a flavonoid found in grapes, green tea, fruits, and vegetables and is not only an antioxidant but also is a pro-oxidant. Myricetin is sparingly soluble in water and restricts its properties due to low bioavailability. The present study reports the liposomal nanoformulations of myricetin to improve its bioavailability with reduced pro-oxidant activity. The nanoformulated myricetin was characterized using different photophysical tools, such as dynamic light scattering (DLS), zeta potential, and scanning electron microscopy (SEM). The effect of nanoencapsulated myricetin on the developing zebrafish embryo was studied in terms of microscopic observations, cumulative hatchability, and antioxidant activities, such as catalase, glutathione peroxidase, and superoxide dismutase, after treating the zebrafish embryo with standard oxidant hydrogen peroxide. The results obtained from the cumulative hatchability, developmental studies, and antioxidant assays indicated that the liposomal nanoformulation of myricetin had enhanced antioxidant activity, leading to defense against oxidative stress. The formulation was highly biocompatible, as evidenced by the cumulative hatching studies as well as microscopic observations. The positive effects of liposomal nanoformulation on zebrafish embryos can open an avenue for other researchers to carry out further related research and to check its activities in clinical studies and developmental studies.

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All Aspects of Antioxidant Properties of Kombucha Drink

Biointerface Research in Applied Chemistry ◽

10.33263/briac123.40184027 ◽

2021 ◽

Vol 12 (3) ◽

pp. 4018-4027

Keyword(s):

Antioxidant Activity ◽

Nutritional Value ◽

Raw Materials ◽

Antioxidant Properties ◽

Human Beings ◽

Healthy Human ◽

Factors Affecting ◽

Beneficial Effects ◽

Main Factors

Nowadays people chose their food and drinks carefully as they are aware of the role of their diet in staying healthy. Human beings are looking for safe, healthy food to get the essential nutrients and have health effects simultaneously. Kombucha, a unique drink, is claimed to have various beneficial effects, and the antioxidant activity is one of the most important ones. Kombucha is mainly based on black and green tea and sugar, but meanwhile, it has been produced by many additional raw materials such as fruit peels, rice, wheat, barley, and honey to add nutritional value and consumer acceptance. This review paper describes the fermentation, biochemistry, and microbiology of kombucha, and also the chemical composition of kombucha was explained along with the main factors affecting the properties of kombucha. This study reviews all aspects of kombucha's antioxidant properties and mentioned the main factors affecting its antioxidant activity.

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Investigation into the Antioxidant Activity of Standardized Plant Extracts with Pharmaceutical Potential

Applied Sciences ◽

10.3390/app11188685 ◽

2021 ◽

Vol 11 (18) ◽

pp. 8685

Author(s):

Elena Moroșan ◽

Magdalena Mititelu ◽

Doina Drăgănescu ◽

Dumitru Lupuliasa ◽

Emma Adriana Ozon ◽

...

Keyword(s):

Antioxidant Activity ◽

Raw Materials ◽

Antioxidant Properties ◽

Natural Antioxidants ◽

Electrochemical Determination ◽

Pharmaceutical Product ◽

Plant Raw Materials ◽

Indirect Evaluation

Given the important role of antioxidants in the cellular degeneration process, as well as the increased interest in recent years related to the use of natural antioxidants in therapy, the present study aims to investigate the antioxidant activity of a new pharmaceutical product containing natural antioxidants extracted from plant raw materials. In a first step, the product conventionally named “CILTAG”, containing a mixture in equal proportions of 10% hydroalcoholic extractive solutions of dried plant raw materials from Medicaginis herba, Trifolii pratense flores, Ginkgo bilobae folium, Myrtilli fructus, and Cynosbati fructus, was obtained. In the second stage, the antioxidant activity of the hydroalcoholic extractive solutions included in the pharmaceutical product was tested by chemiluminescence and electrochemical methods and by the superoxide dismutase (SOD) method. The electrochemical determination of the antioxidant capacity of hydroalcoholic extractive solutions was based on a method that provides an indirect evaluation of the presumed antioxidant properties of some compounds using Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), as a standard measurement. The experimental results indicate a significant antioxidant potential for both the analyzed plant extractive solutions that are part of CILTAG and the final product.

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Study of the biological and antioxidant activity of (Z)-2-(hydroxybenzylidene)-4,6-dihydroxy-7-methylbenzofuran-3(2H)-ones

Butlerov Communications ◽

10.37952/roi-jbc-01/20-61-2-37 ◽

2020 ◽

Vol 61 (2) ◽

pp. 37-45

Author(s):

Dmitry A. Shubin ◽

◽

Dmitry N. Kuznetsov ◽

Konstantin I. Kobrakov ◽

Valentina V. Martazova ◽

...

Keyword(s):

Antioxidant Activity ◽

Chemical Potential ◽

Antioxidant Properties ◽

Metal Electrode ◽

Hydroxyl Groups ◽

Phase Reaction ◽

Total Antioxidant ◽

Academy Of Sciences ◽

Liquid Phase Reaction ◽

Rutin And Quercetin

Studies on the discovery of the chemical potential of 2,4,6-trihydroxytoluene, which has become an affordable reagent in organic synthesis after the development at IPCET SB RAS (Institute for problems of chemical and energetic technologies of the Siberian branch оf the Russian academy of sciences) of technology for its preparation from 2,4,6-trinitrotoluene, we have been conducting systematic studies in recent years to obtain it basis of various multifunctional carbo- and heterocyclic compounds. The paper presents the results of a study of the biological and antioxidant activity of hydroxyderivatives of 2-benzylidenebenzofuran-3(2H)-ones obtained on the basis of 2,4,6-trihydroxytoluene. The compounds studied in the work showed high inhibitory activity against selected test strains (Escherichia coli, Pseudomonas fluorescens, Staphylococcus aureus, Bacillus subtilis). A study of the fungicidal activity of the synthesized compounds showed that the percentage of suppression of fungal strains (Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum, Ulocladium atrum and Penicillium funiculosum) ranges from 0-20%. The antioxidant properties of the synthesized aurons were studied by cyclic voltammetry on a carbon-metal electrode. Ethanol solutions of rutin and quercetin were used as reference standards. The total antioxidant activity (∑AOA) was estimated spectrophotometrically using a liquid-phase reaction with a chromophore radical, 2,2′-diphenyl-1-picrylhydrazyl (DPPH•), according to the degree of “radical uptake” (P). It was shown that all compounds have moderate antioxidant activity, which depends mainly on the number of hydroxyl groups and their position in the compound molecule. The work shows the value of 4,6-dihydroxy-7-methylbenzofuran-3(2H)-one as a building block for combinatorial chemistry.

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Effect of Carbon Black on the Development of Oxidation Processes in Raw and Vulcanized Rubbers

Rubber Chemistry and Technology ◽

10.5254/1.3539868 ◽

1953 ◽

Vol 26 (4) ◽

pp. 858-861 ◽

Cited By ~ 4

Author(s):

A. S. Kuzmixskiĭ ◽

L. I. Lyubchanskaya ◽

N. G. Khitrova ◽

S. I. Bass

Keyword(s):

Carbon Black ◽

Chain Process ◽

Butadiene Rubber ◽

Chain Reactions ◽

Oxidation Processes ◽

Carbon Blacks ◽

Developed Surface ◽

A Chain ◽

Reaction Vessels

Abstract Publications by Rebinder, Ab, and Vei˘ler, Pisarenko and Rebinder, and Dogadkin, Pechkovskaya, and Chernikina have been devoted to an explanation of the mechanism of the accelerating action of carbon blacks. However, only fragmentary and contradictory information about the influence of carbon blacks on the development of oxidation processes is found in scientific literature. In the present article, several important laws regarding the role of channel carbon black in the oxidation of sodium-butadiene rubber are studied. Carbon black can be incorporated in rubber in high proportions (100–125 parts by weight to 100 parts of rubber). It is well known how great is the influence of the surface area of reaction vessels in which the rupture of chains takes place on the development of chain reactions. It is also known that the oxidation of any type of rubber is a chain process of decomposition, with formation of side chains. Therefore in the study of these processes in rubbers, it is necessary to take into account the highly developed surface of contact between the carbon black and rubber particles.

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Role of Carbon in Oxidation of GR-S Vulcanizates

Rubber Chemistry and Technology ◽

10.5254/1.3543280 ◽

1947 ◽

Vol 20 (2) ◽

pp. 469-478 ◽

Cited By ~ 2

Author(s):

Hugh Winn ◽

J. Reid Shelton ◽

David Turnbull

Keyword(s):

Carbon Black ◽

Surface Area ◽

Oxygen Absorption ◽

Quantitative Correlation ◽

Surface Areas ◽

Rapid Absorption ◽

Initial Stage ◽

Different Types ◽

Channel Type

Abstract 1. Carbon black is a catalyst for the oxidation of GR-S vulcanizates. The increased rate of oxygen absorption with increased loading is, however, a function of surface area rather than weight. Different types of carbons show different degrees of activity for a given surface area; the furnace carbons studied were, for example, only 55 per cent as active as channel black in promoting oxidation. 2. The rate constant for the initial rapid absorption of oxygen by GR-S tread stocks is independent of carbon loading. The presence of carbon is, however, essential to activate the centers involved in this initial stage, and the number of activated centers increases with carbon loadings, so that the amount of oxygen absorbed in a given time is also increased. 3. The second or linear stage of oxygen absorption involves two types of reaction with the remaining oxidizable centers in the polymer: a reaction with centers not under the catalytic influence of the carbon black, and a reaction catalyzed by carbon. 4. A theoretical equation was presented which permits the calculation of oxygen absorption by stocks containing either furnace- or channel-type carbons with various surface areas and loadings. The validity of the theory on which the derivation was based is supported by the quantitative correlation of calculated and observed rates of oxygen absorption for stocks containing carbons of both types, with surface areas ranging from 3.7 to 15.7 acres per pound and with loadings of 0 to 75 parts per 100 parts of GR-S. 5. The additional oxygen absorbed at higher loadings of carbon was shown to produce a correspondingly greater deterioration of physical properties.

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