Theoretical study on antioxidant properties of vitamins

Mohajeri, A. and Asemani, S. S. Theoretical study on antioxidant properties of vitamins. In: 11th Iranian Physical Chemistry Seminar-July 2008, July 2008, Ardabil, Iran.

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Abstract

Antioxidants are chemical compounds that can quench reactive radical intermediates formed during the oxidative reaction [1]. Oxidation reaction is the major cause of the irreversible deterioration of biological systems and synthetic polymers. Thermal oxidation of polymers generally corresponds to a free radical chain reaction. Small amounts of antioxidants are added into most synthetic polymers to prevent or retard oxidation and to increase the service lifetime of the products[2]. Phenolic compounds such as phenol acids and some of vitamins are well known as powerful antioxidants[3]. Phenolic antioxidants such as vitamin E, C and caffeic acid are extremely important peroxy radical-trapping agents in human blood plasma and in cells. Free radical scavenging plays an important role in the antioxidant activity of such compounds[4]. Radicals are necessary intermediates in a variety of normal biochemical reaction. Rdical species can cause severe damage to a broad rang of macromolecules. Some of the radicals that are most abundantly produced in biochemical reactions are the so-called reactive oxygen species (ROS)[5]. ROS (·OH, ·OOH,·O2¯) are constantly formed in the human body and must be removed by antioxidant. There are two proposed mechanisms by which antioxidants can play their protective role: hydrogen atom transfer (HAT) and proton-coupled electron transfer (PCET). In fact, both HAT and PCET mechanisms must always occur in parallel, but at different rate [3]. In the HAT pathway, a whole hydrogen atom (H·) is abstracted from a phenol (Ar-OH) by the oxygen of a radical (RO·) using the same sets of orbitals [6]. RO + Ar-OH ROH + Ar-O (1) Thus, it was logical to examine the bond dissociation enthalpy (BDE) of the phenol bond [BDE(Ar-OH)][6]as a good primary indicator of phenol reactivity via HAT Ar-O-H Ar-O + H (2)

Item Type: Conference or Workshop Item (Paper)
Persian Title: Theoretical study on antioxidant properties of vitamins
Persian Abstract: -
Subjects: Divisions > Conferences > 11th Iranian Physical Chemistry Seminar- July 2008
Conferences > 11th Iranian Physical Chemistry Seminar- July 2008
Divisions: Conferences > 11th Iranian Physical Chemistry Seminar- July 2008
Subjects > Conferences > 11th Iranian Physical Chemistry Seminar- July 2008
Date Deposited: 17 Jun 2019 05:15
Last Modified: 17 Jun 2019 05:15
URI: http://repository.uma.ac.ir/id/eprint/6807

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