Evaluation of the anti-oxidative effect (in vitro) of tea polyphenols.
Forty-three polyphenols from tea leaves were evaluated for their anti-oxidative effect against lipid peroxidation by the ferric thiocyanate method in vitro. Among these, 1,4,6-tri-O-galloyl-beta-D-glucose (hydrolyzable tannin) showed the highest anti-oxidative activity against lipid peroxidation, even stronger than that of 3-tert.-butyl-4-hydroxyanisole (BHA). The assay demonstrates that tea polyphenols, except for desgalloylated dimeric proanthocyanidins that possess a catechin structure in the upper unit and desgalloylated flavan-3-ols, and excepting theaflavin 3,3'-di-O-gallate, had more anti-oxidative activity than that of alpha-tocopherol. The chemical structure-activity relationship shows that the anti-oxidative action advanced with the condensation of two molecules of flavan-3-ols as well as with 3-O-acylation in the flavan skeleton such as that by galloyl, (3'-O-methyl)-galloyl, and p-coumaroyl groups.
Faculty of Agriculture, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan. fhashimo@farm.agri.kagoshima-u.ac.jp
Fumio
F
Hashimoto
Masateru
M
Ono
Chikako
C
Masuoka
Yasuyuki
Y
Ito
Yusuke
Y
Sakata
Keiichi
K
Shimizu
Gen-ichiro
G
Nonaka
Itsuo
I
Nishioka
Toshihiro
T
Nohara
D000215:Acylation; D000975:Antioxidants / Q000737:chemistry / Q000494:pharmacology*; D019281:Dimerization; D005419:Flavonoids; D007202:Indicators and Reagents; D007501:Iron / Q000737:chemistry; D015227:Lipid Peroxidation / Q000187:drug effects; D010636:Phenols / Q000737:chemistry / Q000145:classification / Q000494:pharmacology*; D011108:Polymers / Q000737:chemistry / Q000145:classification / Q000494:pharmacology*; D059808:Polyphenols; D013329:Structure-Activity Relationship; D013662:Tea / Q000737:chemistry* / Q000145:classification; D013861:Thiocyanates / Q000737:chemistry
D000975:Antioxidants; D005419:Flavonoids; D007202:Indicators and Reagents; D010636:Phenols; D011108:Polymers; D059808:Polyphenols; D013662:Tea; D013861:Thiocyanates; C103724:ferric thiocyanate; D007501:Iron