Naslov
Mehanizmi oksidacije katehina pri različitim pH istraživani metodom cikličke voltametrije i PM3 semiempirijskim proračunima
(Oxidation Pathways of Catechin at Various pH Studied by Cyclic Voltammetry and PM3 Semi-empirical Calculations)

Autori
Martinez, Sanja ; Valek, Lidija ; Petrović, Željka ; Metikoš-Huković, Mirjana

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
XIX. hrvatski skup kemičara i kemijskih inženjera : Knjiga sažetaka / Škare, D. ; Rapić, V. ; Rogošić, M. - Zagreb : Sveučilišna tiskara, 2005, 150-150

Skup
XIX. hrvatski skup kemičara i kemijskih inženjera

Mjesto i datum
Opatija, Hrvatska, 24.04.2005. - 27.04.2005

Vrsta sudjelovanja
Poster

Vrsta recenzije
Domaća recenzija

Ključne riječi
catehin; oksidacija; ciklička voltamerija
(catehin; oxidation; cyclic voltammetry)

Sažetak
Catechin is frequently used as a phenolic standard in quantification of antioxidative activity and its oxidation mechanism is of interest [1]. It is a representative of a large family of compounds that have the structure of flavone (2-phenyl-chromone) constituted by the two benzene rings (A and B) joined together by a g -pyrone ring (C ring). The basic skeleton suffers a great number of substitutions in the natural compounds and over 4000 different flavanoids are known today. Antioxidant power of a polyphenol in a reaction with a free radical is directly correlated to its ability to act as a reducing agent at an electrode. Although the pK_a values of many polyphenolic compounds, including catechin, are well within the physiological pH range, the influence of pH on the antioxidant activity, determined by chemical or electrochemical methods, has been recognized only in limited number of papers dealing with the subject [2]. In general, a wide span of pH is of interest, including the stomach acid pH 2, wine pH 3.6 and physiological pH 7.4. The motivation of the research was a desire to understand more fully the mechanisms of catechin oxidation at various pH with emphasis on the molecular properties that dictate the chemical and electrochemical oxidation pathways. Catechin oxidation has been investigated by cyclic voltammetry (CV) on a glassy carbon electrode in a pH range of 2-7.4. Based on the parameters deduced from the voltammetric measurements and those calculated by PM3 semiempirical method, the electrochemical oxidation pathway of catechin has been suggested. Possible implications of pH change on the CV method of measuring antioxidant activity are also discussed.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Kemijsko inženjerstvo

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