Electron spin resonance spectroscopic evaluation of scavenging activity of tea catechins on superoxide radicals generated by a phenazine methosulfate and NADH system

The scavenging effects of tea catechins on superoxide radicals ( ·O 2 −) generated non-enzymatically by a phenazine methosulfate (PMS) and reduced β-nicotinamide adenine dinucleotide (NADH) system, was studied using an electron spin resonance (ESR) spectrometer along with a spin-trapping agent, 5, 5...

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Bibliographic Details
Published inFood chemistry Vol. 76; no. 2; pp. 259 - 265
Main Authors Unno, Tomonori, Yayabe, Fumihisa, Hayakawa, Takashi, Tsuge, Haruhito
Format Journal Article
LanguageEnglish
Published Oxford Elsevier Ltd 01.02.2002
Elsevier
Subjects
(−)-Epigallocatechin gallate
Biological and medical sciences
Catechins
Coffee, tea and other stimulative beverage industries
ESR
Food industries
Fundamental and applied biological sciences. Psychology
General aspects
Green tea
Methods of analysis, processing and quality control, regulation, standards
NADH
Phenazine methosulfate
Superoxide radical
Catechins
Phenazine methosulfate
NADH
ESR
(−)-Epigallocatechin gallate
Superoxide radical
Green tea
Radical trapping
Tea
Catechin
Hyperoxides
Tannin
EPR spectrometry
Oxidation
Measurement method
Antioxidant
Energy crop
Biological activity
Free radical
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Summary:The scavenging effects of tea catechins on superoxide radicals ( ·O 2 −) generated non-enzymatically by a phenazine methosulfate (PMS) and reduced β-nicotinamide adenine dinucleotide (NADH) system, was studied using an electron spin resonance (ESR) spectrometer along with a spin-trapping agent, 5, 5-dimethyl-1-pyrroline- N-oxide (DMPO). The presence of 3′, 4′, 5′-trihydroxyl groups attached to the B-ring of the flavan skeleton enhanced the radical scavenging efficiency displayed by the catechin family in comparison to those with 3′, 4′-dihydroxyl groups, and the insertion of a galloyl moiety into three positions of the C-ring exerted a synergistic impact on ·O 2 − scavenging activity. Catechin constituents accounted for 86% of the total ·O 2 − scavenging capacity of green tea extract, with a particularly high contribution ascribed to (−)-epigallocatechin gallate [(−)-EGCG] (48%) and (−)-epigallocatechin [(−)-EGC] (26%).
ISSN:0308-8146
1873-7072
DOI:10.1016/S0308-8146(01)00262-X