Abstract
Radical scavenging effects of tannins and related polyphenols on l,l-diphenyl-2-picrylhydrazyl (DPPH) radical were evaluated by colorimetry. All of the polyphenols examined showed effects much stronger than that of a-tocopherol. The hydrolyzable tannins having galloyl groups in the molecule exhibited stronger effects than those having modified galloyl groups, such as hexahydroxydiphenoyl (HHDP), dehydrohexahydroxydiphenoyl (DHHDP) and chebuloyl groups. (-)-Epigallocatechin gallate, (-)-epigallocatechin, (-)-epicatechin gallate and methyl gallate also showed fairly significant effects, even though they are small molecules. The predominant reaction products upon the treatment of various alkyl gallates with DPPH radical on a preparative scale were dialkyl hexahydroxydiphenates, which should be formed by mutual coupling of C-centered galloyl radicals. Evidence for the formation of the alkyl gallate radicals was also obtained by the electron spin resonance spectroscopy.
| Original language | English |
|---|---|
| Pages (from-to) | 1919-1921 |
| Number of pages | 3 |
| Journal | Chemical and Pharmaceutical Bulletin |
| Volume | 37 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 1989 |
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Keywords
- alkyl gallate
- dialkyl hexahydroxy-diphenate
- hydrolyzable tannin
- l-diphenyl-2-picrylhydrazyl
- radical coupling
- radical scavenger
- tannin l
ASJC Scopus subject areas
- Chemistry(all)
- Drug Discovery
Cite this
Studies on Inhibition Mechanism of Autoxidation by Tannins and Flavonoids : V: Radical-Scavenging Effects of Tannins and Related Polyphenols on l,l-Diphenyl-2-picrylhydrazyl Radical. / Yoshida, Takashi; Mori, Kazuko; Hatano, Tsutomu; Okumura, Tomoko; Uehara, Ikue; Komagoe, Keiko; Okuda, Takuo.
In: Chemical and Pharmaceutical Bulletin, Vol. 37, No. 7, 1989, p. 1919-1921.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Studies on Inhibition Mechanism of Autoxidation by Tannins and Flavonoids
T2 - V: Radical-Scavenging Effects of Tannins and Related Polyphenols on l,l-Diphenyl-2-picrylhydrazyl Radical
AU - Yoshida, Takashi
AU - Mori, Kazuko
AU - Hatano, Tsutomu
AU - Okumura, Tomoko
AU - Uehara, Ikue
AU - Komagoe, Keiko
AU - Okuda, Takuo
PY - 1989
Y1 - 1989
N2 - Radical scavenging effects of tannins and related polyphenols on l,l-diphenyl-2-picrylhydrazyl (DPPH) radical were evaluated by colorimetry. All of the polyphenols examined showed effects much stronger than that of a-tocopherol. The hydrolyzable tannins having galloyl groups in the molecule exhibited stronger effects than those having modified galloyl groups, such as hexahydroxydiphenoyl (HHDP), dehydrohexahydroxydiphenoyl (DHHDP) and chebuloyl groups. (-)-Epigallocatechin gallate, (-)-epigallocatechin, (-)-epicatechin gallate and methyl gallate also showed fairly significant effects, even though they are small molecules. The predominant reaction products upon the treatment of various alkyl gallates with DPPH radical on a preparative scale were dialkyl hexahydroxydiphenates, which should be formed by mutual coupling of C-centered galloyl radicals. Evidence for the formation of the alkyl gallate radicals was also obtained by the electron spin resonance spectroscopy.
AB - Radical scavenging effects of tannins and related polyphenols on l,l-diphenyl-2-picrylhydrazyl (DPPH) radical were evaluated by colorimetry. All of the polyphenols examined showed effects much stronger than that of a-tocopherol. The hydrolyzable tannins having galloyl groups in the molecule exhibited stronger effects than those having modified galloyl groups, such as hexahydroxydiphenoyl (HHDP), dehydrohexahydroxydiphenoyl (DHHDP) and chebuloyl groups. (-)-Epigallocatechin gallate, (-)-epigallocatechin, (-)-epicatechin gallate and methyl gallate also showed fairly significant effects, even though they are small molecules. The predominant reaction products upon the treatment of various alkyl gallates with DPPH radical on a preparative scale were dialkyl hexahydroxydiphenates, which should be formed by mutual coupling of C-centered galloyl radicals. Evidence for the formation of the alkyl gallate radicals was also obtained by the electron spin resonance spectroscopy.
KW - alkyl gallate
KW - dialkyl hexahydroxy-diphenate
KW - hydrolyzable tannin
KW - l-diphenyl-2-picrylhydrazyl
KW - radical coupling
KW - radical scavenger
KW - tannin l
UR - http://www.scopus.com/inward/record.url?scp=85008106302&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85008106302&partnerID=8YFLogxK
U2 - 10.1248/cpb.37.1919
DO - 10.1248/cpb.37.1919
M3 - Article
VL - 37
SP - 1919
EP - 1921
JO - Chemical and Pharmaceutical Bulletin
JF - Chemical and Pharmaceutical Bulletin
SN - 0009-2363
IS - 7
ER -