File Name: oxidation and antioxidants in organic chemistry and biology .zip
Shashank Kumar, Abhay K. There has been increasing interest in the research on flavonoids from plant sources because of their versatile health benefits reported in various epidemiological studies.
- Chemistry and Biological Activities of Flavonoids: An Overview
- Antioxidant Compounds and Their Antioxidant Mechanism
- Read Oxidation and Antioxidants in Organic Chemistry and Biology PDF Online
- Antioxidant Chemistry of α-Tocopherol in Biological Systems
Chemistry and Biological Activities of Flavonoids: An Overview
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In chemistry , a radical more precisely, a free radical is an atom , molecule , or ion that has unpaired valence electrons or an open electron shell , and therefore may be seen as having one or more "dangling" covalent bonds. With some exceptions, these "dangling" bonds make free radicals highly chemically reactive towards other substances, or even towards themselves: their molecules will often spontaneously dimerize or polymerize if they come in contact with each other. Most radicals are reasonably stable only at very low concentrations in inert media or in a vacuum. Free radicals may be created in a number of ways, including synthesis with very dilute or rarefied reagents, reactions at very low temperatures, or breakup of larger molecules. The latter can be affected by any process that puts enough energy into the parent molecule, such as ionizing radiation , heat, electrical discharges, electrolysis , and chemical reactions. Indeed, radicals are intermediate stages in many chemical reactions. Free radicals play an important role in combustion, atmospheric chemistry , polymerization, plasma chemistry, biochemistry , and many other chemical processes.
An antioxidant is a substance that at low concentrations delays or prevents oxidation of a substrate. Antioxidant compounds act through several chemical mechanisms: hydrogen atom transfer HAT , single electron transfer SET , and the ability to chelate transition metals. The importance of antioxidant mechanisms is to understand the biological meaning of antioxidants, their possible uses, their production by organic synthesis or biotechnological methods, or for the standardization of the determination of antioxidant activity. In general, antioxidant molecules can react either by multiple mechanisms or by a predominant mechanism. The chemical structure of the antioxidant substance allows understanding of the antioxidant reaction mechanism. This chapter reviews the in vitro antioxidant reaction mechanisms of organic compounds polyphenols, carotenoids, and vitamins C against free radicals FR and prooxidant compounds under diverse conditions, as well as the most commonly used methods to evaluate the antioxidant activity of these compounds according to the mechanism involved in the reaction with free radicals and the methods of in vitro antioxidant evaluation that are used frequently depending on the reaction mechanism of the antioxidant.
Antioxidant Compounds and Their Antioxidant Mechanism
Beneficial renal effects of some medications, such as chelation therapy depend at least partially on the ability to alleviate oxidative stress. The administration of various natural or synthetic antioxidants has been shown to be of benefit in the prevention and attenuation of metal induced biochemical alterations. Human studies are limited in this regard. Under certain conditions, surprisingly, the antioxidant supplements may exhibit pro-oxidant properties and even worsen metal induced toxic damage. To date, the evidence is insufficient to recommend antioxidant supplements in subject with exposure to metals.
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Read Oxidation and Antioxidants in Organic Chemistry and Biology PDF Online
Open Chemistry is a peer-reviewed, open access journal that publishes original research, reviews and communications in the fields of chemistry in an ongoing way. Our central goal is to provide a hub for researchers working across all subjects to present their discoveries, and to be a forum for the discussion of the important issues in the field. Our journal is the premier source for cutting edge research in fundamental chemistry and it provides high quality peer review services for its authors across the world. Moreover, it allows for libraries everywhere to avoid subscribing to multiple local publications, and to receive instead all the necessary chemistry research from a single source available to the entire scientific community.
Antioxidant Chemistry of α-Tocopherol in Biological Systems
The normal biochemical reactions in our body, increased exposure to the environment, and higher levels of dietary xenobiotic's result in the generation of reactive oxygen species ROS and reactive nitrogen species RNS. The reported chemical evidence suggests that dietary antioxidants help in disease prevention. Therefore, it is very important to understand the reaction mechanism of antioxidants with the free radicals. This review elaborates the mechanism of action of the natural antioxidant compounds and assays for the evaluation of their antioxidant activities. The reaction mechanisms of the antioxidant assays are briefly discussed references. Practical applications: understanding the reaction mechanisms can help in evaluating the antioxidant activity of various antioxidant compounds as well as in the development of novel antioxidants. Normal biochemical reactions, increased exposure to the environment, and higher levels of dietary xenobiotics result in the generation of reactive oxygen species ROS and reactive nitrogen species RNS.
Free radicals and other oxidants have gained importance in the field of biology due to their central role in various physiological conditions as well as their implication in a diverse range of diseases. The free radicals, both the reactive oxygen species ROS and reactive nitrogen species RNS , are derived from both endogenous sources mitochondria, peroxisomes, endoplasmic reticulum, phagocytic cells etc. Free radicals can adversely affect various important classes of biological molecules such as nucleic acids, lipids, and proteins, thereby altering the normal redox status leading to increased oxidative stress.
Enter your mobile number or email address below and we'll send you a link to download the free Kindle App. Then you can start reading Kindle books on your smartphone, tablet, or computer - no Kindle device required. To get the free app, enter your mobile phone number. Providing a comprehensive review of reactions of oxidation for different classes of organic compounds and polymers, and biological processes mediated by free radicals, Oxidation and Antioxidants in Organic Chemistry and Biology puts the data and bibliographical information you need into one easy-to-use resource. You will find up-to-date information about mechanisms of action of antioxidants, their reactivity, reactions of intermediates, synergism, and antioxidants with cyclic mechanism action.
Oxidation and Antioxidants in Organic Chemistry and Biology By PDF (21 KB) II is a discussion of the chemistry of antioxidants (7 chapters); and Part III is an analysis of biological oxidations, broadly defined (12 chapters).
Только подумайте. Беккер встревожился: - Так кольца у вас. - Боже мой, конечно. Беккер ощутил тупую боль в желудке. - У кого же. В глазах Клушара вспыхнуло возмущение.
Сьюзан хотела что-то сказать, но ее опередил Джабба: - Значит, Танкадо придумал шифр-убийцу. - Он перевел взгляд на экран. Все повернулись вслед за .
Компьютер немедленно распознал частоту ее голоса, и дверь, щелкнув, открылась. Сьюзан проследовала. Охранник залюбовался Сьюзан, шедшей по бетонной дорожке. Он обратил внимание, что сегодня взгляд ее карих глаз казался отсутствующим, но на щеках играл свежий румянец, а рыжеватые до плеч волосы были только что высушены. От нее исходил легкий аромат присыпки Джонсонс беби.
Нет, конечно. Я просто подумал… - Толстяк быстро убрал бумажник.