Effects of Dietary Tea Catechins on .ALPHA.-Tocopherol Levels, Lipid Peroxidation, and Erythrocyte Deformability in Rats Fed on High Palm Oil and Perilla Oil Diets.

Nanjo, Fumio; Honda, Miwa; Okushio, Kazuo; Matsumoto, Natsuki; Ishigaki, Fumiko; Ishigami, Tadashi; Hara, Yukihiko

doi:10.1248/bpb.16.1156

Cited by 97 publications

(61 citation statements)

References 2 publications

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“…Consumption of the flavonoids at the doses (mean intake, 25 mg/day) used in this study was without negative effects on animal performance (Table 1), in accordance with results published by other researchers, some of which used even higher doses (23,(35)(36)(37)(38). In this investigation, all three dietary flavonoids substantially increased the blood and liver concentrations of a-T (Table 2).…”

Section: Discussionsupporting

confidence: 90%

“…These findings are supported by other studies that used mixtures of flavonoids and a different strain of rats. For example, male Wistar rats had increased a-T concentrations in their plasma and liver microsomes when fed 0.8% Q and C (2:1, w/w) for 4 weeks in their diets (36) and in plasma and erythrocytes after consuming a mixture of tea catechins containing EC and C (580 and 140 mg/kg diet, respectively) (38). On the other hand, no increase in a-T concentrations was reported in male Sprague-Dawley rats after C or Q consumption at 0.3% (w/w) in the diet (37).…”

Section: Discussionmentioning

confidence: 99%

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Dietary flavonoids with a catechol structure increase α-tocopherol in rats and protect the vitamin from oxidation in vitro

Frank

Budek

Lundh

et al. 2006

Journal of Lipid Research

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To identify dietary phenolic compounds capable of improving vitamin E status, male Sprague-Dawley rats were fed for 4 weeks either a basal diet (control) with 2 g/kg cholesterol and an adequate content of vitamin E or the basal diet fortified with quercetin (Q), (2)-epicatechin (EC), or (1)-catechin (C) at concentrations of 2 g/kg. All three catechol derivatives substantially increased concentrations of a-tocopherol (a-T) in blood plasma and liver. To study potential mechanisms underlying the observed increase of a-T, the capacities of the flavonoids to i ) protect a-T from oxidation in LDL exposed to peroxyl radicals, ii ) reduce a-tocopheroxyl radicals (a-T˙) in SDS micelles, and iii ) inhibit the metabolism of tocopherols in HepG2 cells were determined. All flavonoids protected a-T from oxidation in human LDL ex vivo and dose-dependently reduced the concentrations of a-T˙. None of the test compounds affected vitamin E metabolism in the hepatocyte cultures. In conclusion, fortification of the diet of Sprague-Dawley rats with Q, EC, or C considerably improved their vitamin E status. The underlying mechanism does not appear to involve vitamin E metabolism but may involve direct quenching of free radicals or reduction of the a-T˙by the

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Dietary flavonoids with a catechol structure increase α-tocopherol in rats and protect the vitamin from oxidation in vitro

Frank

Budek

Lundh

et al. 2006

Journal of Lipid Research

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“…palm and perilla oil diets prevents a-tocopherol concentration from decreasing in rat plasma (19). Oral or intravenous dosing of GT epimer mixture (4000 mg/kg body weight) increases the total plasma antioxidant potential in rats by increasing the FRAP value (4).…”

Section: Vg Raneva and H Shimasakimentioning

confidence: 99%

Green Tea Catechins Decrease Lipid Peroxidation in Plasma and Organs of C57BL/6J Mice Fed Atherogenic Diet

Raneva

Shimasaki

2005

J. Oleo Sci.

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It is known that the active oxygen species could promote atherosclerosis, cancer, and aging. The antioxidants by scavenging free radicals or deactivating active oxygen species diminish the oxidation processes in vivo. We have shown that in artificial liposomal membranes the green tea catechins ( )-epigallocatechin gallate (EGCG), ( )-epicatechin gallate (ECG), ( )-epigallocatechin (EGC) and ( )-epicatechin (EC) are strong antioxidants acting by scavenging free radicals and/or regenerating a-tocopherol, the most abundant in LDL lipophilic antioxidant (1). Also we have demonstrated that oral supplementation of the most distributed green tea catechin and one of the most powerful polyphenol antioxidants EGCG preserves the inner rat Abstract: Green tea catechins (TC) have anti-obesity effects on atherosclerosis-susceptible mice fed atherogenic diet, but the antioxidant effect of the catechins at these conditions is not studied. Our aim is to show that green tea catechins have a favorable effect on plasma and organs lipid peroxidation parameters. For the purpose we have fed atherosclerosis-susceptible mice HF (30 %) diet containing TC (0.5 %). We have measured body weight, food intake, ferric-reducing ability of plasma (FRAP), total cholesterol and a-tocopherol concentrations in plasma, and lipid hydroperoxides concentrations in liver and small intestine, and compared them with these in control group fed HF diet. Also we have measured ECG and EGCG concentrations in plasma, liver, and small intestine of the mice fed TC. Our results show that green tea catechins' feeding reduces the body weight without affecting the food intake. TC group FRAP values are significantly different from these in the control group at all investigated periods. a-Tocopherol plasma concentrations in TC group have greater values than these in the control group. TC group liver and small intestine lipid hydroperoxides concentrations are lower than these in HF group. In conclusion, our results show that green tea catechins' feeding leads to catechins accumulation in plasma, liver, and small intestine which causes anti-lipid peroxidation effects in atherosclerosissusceptible mice.

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“…EGCG is widely accepted as an antioxidant. For example, EGCG scavenges superoxide anion radicals (O 2 ·Ϫ ), hydrogen peroxide (H 2 O 2 ), hydroxy radicals (HO · ), peroxyl radicals, singlet oxygen, and peroxynitrite (5,16,17,45,47,49,56). The one-electron reduction potential of EGCG under standard conditions is 550 mV, a value lower than that of glutathione (920 mV) and comparable to that of ␣-tocopherol (480 mV) (13,24,25).…”

mentioning

confidence: 99%

Green Tea Polyphenols Function as Prooxidants To Activate Oxidative-Stress-Responsive Transcription Factors in Yeasts

Maeta

Nomura

Takatsume

et al. 2007

Appl Environ Microbiol

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Epigallocatechin gallate (EGCG) is the most abundant polyphenolic flavonoid in green tea. Catechin and its derivatives, including EGCG, are widely believed to function as antioxidants. Here we demonstrate that both EGCG and green tea extract (GTE) cause oxidative stress-related responses in the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe under weak alkaline conditions in terms of the activation of oxidative-stress-responsive transcription factors. GTE as well as EGCG induced the nuclear localization of Yap1 in S. cerevisiae, which was repressed by the addition of catalase but not by the addition of superoxide dismutase. The same phenomena were observed for the nucleocytoplasmic localization of Msn2 in S. cerevisiae and Pap1, a Yap1 homologue, in S. pombe. The formation of intramolecular disulfide bonds has been proposed to be crucial for the H 2 O 2 -induced nuclear localization of Yap1, and we verified the importance of cysteine residues of Yap1 in response to EGCG and GTE. Additionally, we show that EGCG and GTE produce H 2 O 2 in a weak alkaline medium. Finally, we conclude that tea polyphenols are able to act as prooxidants to cause a response to oxidative stress in yeasts under certain conditions.Green tea is one of the beverages consumed in the highest quantity in the world. Epidemiologic research has revealed that individuals who drink a lot of green are less likely to develop cancer (28,30,51,64). Very recently, a relationship between the consumption of green tea and a reduced risk of type 2 diabetes was reported (23). Green tea contains many ingredients considered to promote health such as polyphenolic flavonoids, of which epigallocatechin gallate (EGCG) is the major constituent. Evidence is mounting that EGCG has anticarcinogenic activity in vitro (3,8,27,61), which may support the results of the epidemiologic research on the correlation between drinking green tea and the risk of morbidity from cancer.Many studies have been done on the biological activity of green tea extract (GTE) and individual catechins in vitro. EGCG is widely accepted as an antioxidant. For example, EGCG scavenges superoxide anion radicals (O 2 ·Ϫ ), hydrogen peroxide (H 2 O 2 ), hydroxy radicals (HO · ), peroxyl radicals, singlet oxygen, and peroxynitrite (5,16,17,45,47,49,56). The one-electron reduction potential of EGCG under standard conditions is 550 mV, a value lower than that of glutathione (920 mV) and comparable to that of ␣-tocopherol (480 mV) (13,24,25). Besides directly scavenging reactive oxygen/nitrogen species, EGCG chelates redox-active metal ions, such as iron and copper, leading to a reduction in the production of reactive oxygen species. Accordingly, many food supplements or beverages containing a high concentration of EGCG (Ͼ1 mM) have been developed, and therefore, the physiological function of EGCG in vivo with a high-dose ingestion remains to be elucidated.In contrast to its antioxidative activity, recent experiments in vitro indicate that EGCG produces reactive oxy...

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Effects of Dietary Tea Catechins on .ALPHA.-Tocopherol Levels, Lipid Peroxidation, and Erythrocyte Deformability in Rats Fed on High Palm Oil and Perilla Oil Diets.

Cited by 97 publications

References 2 publications

Dietary flavonoids with a catechol structure increase α-tocopherol in rats and protect the vitamin from oxidation in vitro

Dietary flavonoids with a catechol structure increase α-tocopherol in rats and protect the vitamin from oxidation in vitro

Green Tea Catechins Decrease Lipid Peroxidation in Plasma and Organs of C57BL/6J Mice Fed Atherogenic Diet

Green Tea Polyphenols Function as Prooxidants To Activate Oxidative-Stress-Responsive Transcription Factors in Yeasts

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