Peroxynitrite-Scavenging Activity of Green Tea Tannin

Chung, Hae Young; Yokozawa, Takako; Soung, Do Y.; Kye, In Sook; No, Jae Kyung; Baek, Bong Sook

doi:10.1021/jf980556u

Cited by 54 publications

(38 citation statements)

References 15 publications

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“…Under these conditions, considerable alterations in the metabolism of Cr, which accumulates in blood as renal failure progresses, are accelerated (i.e., Cr is oxidized to MG), suggesting that antioxidants that scavenge •OH may be useful therapeutic avenues for inhibition of MG production and further prevention of uremic symptoms. Green tea polyphenols have been shown to act as metal chelators, preventing metal-catalyzed formation of radical species, antioxidant enzyme modulators, and scavengers of free radicals, including •OH, superoxide anion, nitric oxide, and peroxynitrite (2, [29][30][31]. These antioxidant activities are considered to be closely related to their protective effects against various diseases, including renal disease, arteriosclerosis, cancer, and inflammation caused by lipid peroxidation and excessive free radical production (32).…”

Section: Discussionmentioning

confidence: 99%

Activity of (−)-Epigallocatechin 3-O-Gallate against Oxidative Stress in Rats with Adenine-Induced Renal Failure

Nakagawa¹,

Yokozawa²,

M³

et al. 2004

J. Agric. Food Chem.

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Methylguanidine (MG) is widely recognized as a strong uremic toxin. The hydroxyl radical (*OH) specifically plays an important role in the pathway of MG production from creatinine (Cr). In this study, we investigated whether oral administration of (-)-epigallocatechin 3-O-gallate (EGCg) suppresses MG production in rats with chronic renal failure after intraperitoneal Cr injection. MG production from Cr was significantly increased in rats with adenine-induced renal failure, which was more vulnerable to oxidative stress, compared with that in normal rats. However, oral administration of EGCg 30 min before and after Cr injection effectively inhibited MG production. Our findings suggest that EGCg, an excellent antioxidant from green tea, exerts protective activity in rats with chronic renal failure, resulting in suppression of Cr oxidation influenced by *OH.

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Section: Discussionmentioning

confidence: 99%

Activity of (−)-Epigallocatechin 3-O-Gallate against Oxidative Stress in Rats with Adenine-Induced Renal Failure

Nakagawa¹,

Yokozawa²,

M³

et al. 2004

J. Agric. Food Chem.

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“…They have been reported to provide benefits with regard to the amelioration of inflammation and oxidative stress, and have also been shown to exert positive effects in cancer, cardiovascular and chronic inflammatory diseases (Middleton et al 2000;Stavric 1994). Green tea polyphenols have been reported to protect normal epithelial cells against ROS (Chung et al 1998). However, thus far, no studies have been conducted to evaluate the potential effects of flavonoids associated with ROS and inflammation in aged gingival tissues.…”

Section: Introductionmentioning

confidence: 99%

Down-regulation of iNOS and TNF-α expression by kaempferol via NF-κB inactivation in aged rat gingival tissues

et al. 2007

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The primary objective of this study was to evaluate the ability and mechanism of action of kaempferol, which is contained in extracts from Nelumbo nucifera, a well-known Oriental herb used in traditional medicine, with regard to the inhibition of iNOS and TNF-alpha expression in aged rat gingival tissues. We conducted an investigation into the age-related effects of kaempferol on reactive oxygen species (ROS) and GSH oxidative status in samples of aged gingival tissues. Western blotting was conducted in order to determine the expression of iNOS, TNF-alpha, p38 MAPK, NIK/IKK, p65 and IkappaBalpha in the sample tissues. Electrophoretic mobility shift assays (EMSA) were conducted in an effort to characterize the binding activities of NF-kappaB transcription factors in the aged rat gingival nuclear extracts. Our results indicate that kaempferol reduced ROS levels and augmented GSH levels in a dose-dependent manner in the aged gingival tissues. Kaempferol was shown to effect a significant reduction in iNOS and TNF-alpha protein levels, as compared to control gingival tissue samples. The results of Western blot analysis revealed that kaempferol treatment effected the reduction of iNOS and TNF-alpha expression, decreased nuclear p65 and increased cytosolic p65, down-regulation of Erk, p38, JNK and NIK/IKK expression. The EMSA results also indicated that kaempferol, when administered to the rat tissues, attenuated the NF-kappaB nuclear binding activity. Kaempferol may inhibit ROS generation via the inhibition of iNOS and TNF-alpha expression in aged gingival tissues, via the modulation of the NF-kappaB and mitogen-activated protein kinase (MAPK) pathways.

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“…In recent years, the importance of the physiological, biochemical, biological and cytotoxic properties of biologically produced peroxynitrite has been recognized. Consequently, the scavenging activity of flavonoids and phenolic non-flavonoids compounds has been widely studied (Chung et al, 1998;Haenen et al, 1997;Ohshima et al, 1998;Kono et al, 1997;Pannala et al, 1998;Grace et al, 1998). Flavonoids occur frequently in the natural diet.…”

Section: Introductionmentioning

confidence: 99%

The structure–activity relationship of flavonoids as scavengers of peroxynitrite

Choi

Chung

Kang

et al. 2002

Phytotherapy Research

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Peroxynitrite is a cytotoxic intermediate produced by the reaction between a superoxide anion radical and nitric oxide. The scavenging activities of flavonoids on peroxynitrite were investigated to illustrate the structure-activity relationship. Peroxynitrite was scavenged by the presence of various flavonoids, whose structures seem to be closely related to the degree of scavenging. Of 31 compounds tested, the most active was quercetin, with an IC50 value of 0.93 microM. Others had IC50 values ranging from 0.96 to more than 10 microM. The scavenging activity was postulated to be governed by the position of the hydroxyl group. Ortho-hydroxyl structures increased the scavenging activity on peroxynitrite.

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Peroxynitrite-Scavenging Activity of Green Tea Tannin

Cited by 54 publications

References 15 publications

Activity of (−)-Epigallocatechin 3-O-Gallate against Oxidative Stress in Rats with Adenine-Induced Renal Failure

Activity of (−)-Epigallocatechin 3-O-Gallate against Oxidative Stress in Rats with Adenine-Induced Renal Failure

Down-regulation of iNOS and TNF-α expression by kaempferol via NF-κB inactivation in aged rat gingival tissues

The structure–activity relationship of flavonoids as scavengers of peroxynitrite

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