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Comparative Study of Antioxidant Properties and Cytoprotective Activity of Flavonoids

A. I. Potapovich and V. A. Kostyuk*

School of Biology, Belorussian State University, pr. F. Skoriny 4, Minsk 220050, Belarus; fax: 375 (172) 77-5535; E-mail: kostyuk@bsu.by

* To whom correspondence should be addressed.

Received February 14, 2002; Revision received May 15, 2002

Antioxidant properties and cytoprotective activity of flavonoids (rutin, dihydroquercetin, quercetin, epigallocatechin gallate (EGCG), epicatechin gallate (ECG)) were studied. All these compounds inhibited both NADPH- and CCl4-dependent microsomal lipid peroxidation, and the catechins were the most effective antioxidants. The I50 values calculated for these compounds by regression analysis were close to the I50 value of the standard synthetic antioxidant ionol (2,6-di-tert-butyl-4-methylphenol). The antiradical activity of flavonoids to O2-* was studied in a model photochemical system. Rate constants of the second order reaction obtained by competitive kinetics suggested flavonoids to be more effective scavengers of oxygen anion-radicals than ascorbic acid. By competitive replacement all flavonoids studied were shown to be chelating agents capable of producing stable complexes with transition metal ions (Fe2+, Fe3+, Cu2+). The flavonoids protected macrophages from asbestos-induced damage, and the protective effect increased in the following series: rutin < dihydroquercetin < quercetin < ECG < EGCG. The cytoprotective effect of flavonoids was in strong positive correlation with their antiradical activity to O2-*.


KEY WORDS: antioxidants, flavonoids, oxidative stress, reactive oxygen species, asbestos, rutin, quercetin, epicatechins