文章基本信息

标题：The Contribution of the Pyrogallol Moiety to the Superoxide Radical Scavenging Activity of Flavonoids
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作者：Koji Furuno ; Toyokazu Akasako ; Narumi Sugihara 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：2002
卷号：25
期号：1
页码：19-23
DOI：10.1248/bpb.25.19
出版社：The Pharmaceutical Society of Japan
摘要：Sixteen flavonoids including flavonols, flavones, flavanonol and catechins, and five aromatic compounds were examined for their ability to scavenge superoxide radical (O₂⁻) generated enzymatically in a xanthin–xanthinoxidase system and non-enzymatically in a phenazine methosulfate–NADH system. Pyrogallol, gallic acid and its ester, were much more efficient in scavenging O₂⁻ than catechol. The superiority of pyrogallol over catechol in the flavonoidal nucleus is apparent from the much higher O₂⁻ scavenging activity of myricetin and epigallocatechin, which contain 3′, 4′, 5′-trihydroxyl substitution in the B-ring, compared to quercetin and epicatechin, which contain 3′, 4′-dihydroxyl substitution, respectively. The strong O₂⁻ scavenging ability of pyrogallol appears to function even in the A-ring, as in baicalein, and also in the form of a pyrogalloyl ester at the C-3 position in the C-ring, as in epicatechin gallate and epigallocatechin gallate. It can be concluded that the pyrogallol moiety is an active component of flavonoids for displaying high O₂⁻ scavenging activity. Flavonoids and aromatics were also examined to correlate their O₂⁻ scavenging activity with their oxidizability, which was measured on the basis of electrochemical redox potential and the reducing ability of the Cu²⁺ ion. Aromatics such as pyrogallol, gallic acid and its ester, and flavonoids such as baicalein, epicatechin gallate and epigallocatechin gallate, in which the O₂⁻ scavenging activity is enhanced by the presence of a pyrogallol moiety which does not belong to the B-ring, reduced the correlation between the higher O₂⁻ scavenging activity and the lower redox potential. The O₂⁻ scavenging activity was well correlated with the Cu²⁺ reducing ability of flavonoids and aromatics.
关键词：flavonoid;oxidizability;superoxide radical scavenging activity