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POTENT RADICAL SCAVENGING ABILITY OF SUNPHENON: A GREEN TEA EXTRACT
Author(s) -
KAVIARASAN S.,
SIVAKUMAR A.S.,
BARIK A.,
KUNWAR A.,
NAIK G.H.,
PRIYADARSINI K.I.
Publication year - 2011
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.2010.00404.x
Subject(s) - chemistry , radical , hydroxyl radical , ascorbic acid , radiolysis , singlet oxygen , photochemistry , superoxide dismutase , scavenging , antioxidant , scavenger , nuclear chemistry , medicinal chemistry , oxygen , organic chemistry , food science
Sunphenon (BG), a polyphenol rich fraction of green tea, which exhibits potent anti‐oxidant and anticancer activity, was examined for its ability to react with free radicals and singlet oxygen using fast reaction kinetic tools. Employing nanosecond pulse radiolysis technique, hydroxyl ( • OH) radical scavenging ability of sunphenon was compared with a standard thiocyanate anion, which indicated that sunphenon reacts with • OH produced a transient absorption spectrum with λ max at 380 and 480 nm, which is characteristic of gallocatechin phenoxyl radicals. It also scavenges singlet oxygen very efficiently and decreases its life time from 64 to 21 µs on addition of 4.5 mg/mL of sunphenon and the nitric oxide (NO), superoxide (O 2 •− ) and hydroxyl radical scavenging actions of sunphenon were estimated by steady state methods. Sunphenon showed higher reactivity towards 2,2′‐diphenyl‐1‐picrylhydrazyl radicals as compared to ascorbic acid with an IC 50 value of 6.9 mg/mL and possesses ∼89 % ascorbate equivalents in scavenging 2,2′‐azino‐bis (3‐thylbenz‐thiazoline‐6‐sulfonic acid •− . Cyclic voltammetry of sunphenon showed two oxidation peaks with peak at a potential of 0.33 V and 0.74 V, indicative of its redox potential. Sunphenon protects peroxide‐induced damage to mitochondrial superoxide dismutase (SOD) and inhibits radiation induced DNA damage in plasmid pBR322 DNA. Based on these studies, it is confirmed that sunphenon is one of the richest sources of free radical scavengers. The free radical scavenging ability of sunphenon is as high as any pure compound, a property which is not seen in many extracts.PRACTICAL APPLICATIONS Our study envisage the potential properties of sunphenon, a green tea polyphenol by its anti‐oxidant activity of scavenging free radicals such as hydroxyl, superoxide, nitric oxide, singlet oxygen, 2,2′‐azino‐bis (3‐thylbenz‐thiazoline‐6‐sulfonic acid •− and 2,2′‐diphenyl‐1‐picrylhydrazyl and also possesses protective action against peroxide‐induced mitochondrial damage, radiation induced DNA damage and having high redox potential. Based on its potential ability it might be useful in filed of drug discovery for making novel drugs or nanoparticles for treating various diseases.