کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10738964 | 1046849 | 2005 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Structure-property studies on the antioxidant activity of flavonoids present in diet
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کلمات کلیدی
SDSCTAB2′-deoxyguanosine - 2'-deoxyguanosine8-hydroxy-2′-deoxyguanosine - 8-هیدروکسی-2'-دگزسی گوانوزینDFT - DFTtaxifolin - taxfilincetyltrimethylammonium bromide - اتلی تریمتیل آمونیوم برومیدSpar - اسپارFormation constants - تشکیل ثابتAcidity constants - ثابت اسیدیتهsodium dodecyl sulfate - سدیم دودسیل سولفاتPartition coefficients - ضرایب پارتیشنAntioxidant activity - فعالیت آنتیاکسیدانیFlavonoids - فلاونوئیدهاAb initio calculations - محاسبات اولیه ابتدائیCopper (II) - مس (II)Density functional theory - نظریه تابعی چگالیHexadecylphosphocholine - هگزادسیل فسفو هولینCatechin - کاتچین، کتیچین
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
سالمندی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The screening of natural flavonoids for their bioactivity as antioxidants is usually carried out by determinination of their profile as chain-breaking antioxidants, by the evaluation of their direct free radical-scavenging activity as hydrogen- or electron-donating compounds. Since this may not be the only mechanism underlying the antioxidant activity it is important to check the ability of these compounds to act as chelators of transition metal ions. Accordingly, in the present study the acidity constants of catechin and taxifolin, as well as the formation constants of the corresponding copper (II) complexes, were investigated by potentiometry and/or spectrophotometry. Moreover, a detailed quantitative examination of the coordination species formed is presented. In addition, the partition coefficients of both catechin and taxifolin in a biomimetic system (micelles) were determined, since these properties may also contribute to the antioxidant behavior of this type of compound. The log P values determined depend on the electrostatic interactions of the compounds with the differently charged micelles (the highest values were obtained for zwitterionic and cationic micelles). The prooxidant behavior of the compounds was assessed through the oxidation of 2â²-deoxyguanosine, induced by a Fenton reaction, catalyzed by copper. The data obtained reveal that the flavonoids under study did not present prooxidant activity, in this particular system. The results obtained are evidence of a clear difference among the pKa, the complexation properties, and the lipophilicity of the flavonoids studied, which can partially explain their distinct antioxidant activity. The most stable geometries of the free compounds were determined by theoretical (ab initio) methods, in order to properly account for the electron correlation effects which occur in these systems, thus allowing a better interpretation of the experimental data.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Free Radical Biology and Medicine - Volume 39, Issue 8, 15 October 2005, Pages 1099-1108
Journal: Free Radical Biology and Medicine - Volume 39, Issue 8, 15 October 2005, Pages 1099-1108
نویسندگان
Susana Teixeira, Christophe Siquet, Carla Alves, Isabel Boal, M. Paula Marques, Fernanda Borges, José L.F.C. Lima, Salette Reis,