Green tea catechins such as (−)‐epicatechin and (−)‐epigallocatechin accelerate Cu<sup>2+</sup>‐induced low density lipoprotein oxidation in propagation phase

Yamanaka, Naoaki; Oda, Osamu; Nagao, Seiji

doi:10.1016/s0014-5793(96)01455-x

Cited by 112 publications

(66 citation statements)

References 19 publications

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“…37) However, in the present study, KBG did not show any pro-oxidative action, quite different from vitamin E. The reason for the discrepancy between the Kampo formulas (OGT and KBG) and vitamin E might be explained by the fact that a Kampo formulation consists of multiple ingredients (as shown in Figs. 1 and 2).…”

Section: Fig 1 Effects Of Kampo Medicines On Progression Of Atheromcontrasting

confidence: 65%

Oren-gedoku-to and Keishi-bukuryo-gan-ryo Inhibit the Progression of Atherosclerosis in Diet-Induced Hypercholesterolemic Rabbits

Sekiya

Kainuma

Hikiami

et al. 2005

Biological & Pharmaceutical Bulletin

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Many investigations have indicated that elevated serum cholesterol levels may modify the biochemical properties of blood components and arterial intima, thus enhancing the progression of atherosclerosis.1-3) Atherosclerosis brings about cerebrovascular disease and coronary artery disease. The cholesterol-fed rabbit is an animal model for hypercholesterolemia and atheromatous formation. Formerly, we clarified that Keishi-bukuryo-gan-ryo (KBG, Gui-zhi-fu-ling-wan in Chinese) prevents the development of atheromatous plaque formation in the aorta of cholesterol-fed rabbits by its antioxidative effect. 4) Vitamin E is a lipid-soluble antioxidant that inhibits lipid peroxidation and attenuates atherosclerosis. However, other studies showed that vitamin E might be a pro-oxidant. 5-7)Oren-gedoku-to (OGT, Huanlian-jie-du-tang in Chinese) is a Kampo formulation consisting of four medicinal plants (Table 1). It has been used for the treatment of cerebrovascular disease, hypertension, gastritis and liver disease in Japan. Several studies have shown that OGT scavenges superoxide anions and hydroxyl radicals in vitro. 8,9) Furthermore, it has been revealed that ingestion of OGT strengthens the protection of RBC membrane in oxidative stress, and improves protein and lipid metabolisms in human. 10,11) In this study, we investigated whether OGT is able to inhibit the progression of atheromatous formation in cholesterol-fed rabbits. Moreover, we compared the effect of OGT with those of KBG and vitamin E. MATERIALS AND METHODS Reagents. Medicines OGT (TJ-15) and KBG (TJ-25)were kindly provided by Tsumura & Co. Powdered extract of OGT was obtained from 4 kinds of medicinal plants mixed at the ratios shown in Table 1, and that of KBG was from 5 medicinal plants (Table 2). These nine medicinal plants are registered in the Japanese Pharmacopoeia.Animals Male Japanese white rabbits weighing 2 kg were purchased from Sankyo Laboratories (Toyama, Japan). Twenty-four rabbits were randomly divided into four groups. Medicine, Oriental Medical Center, Iizuka Hospital; Iizuka, Japan: c Department of Kampo Diagnostics, Institute of Wakan-yaku, Toyama Medical and Pharmaceutical University; Sugitani 2630, Toyama 930-0194, Japan: and d 21st Century COE Program, Toyama Medical and Pharmaceutical University; Sugitani 2630, Toyama 930-0194, Japan. Received September 9, 2004 accepted November 12, 2004; published online November 18, 2004 In this study, we examined whether the Kampo formulas Oren-gedoku-to (OGT, Huanglian-jie-du-tang in Chinese) and Keishi-bukuryo-gan-ryo (KBG, Gui-zhi-fu-ling-wan in Chinese) could prevent the progression of atherosclerosis in cholesterol-fed rabbit, an animal model for hypercholesterolemia in vivo. Twenty-four male Japanese white rabbits (2 kg body weight) were divided into four groups. The control group was fed standard rabbit chow containing 1% cholesterol, the OGT group was fed standard rabbit chow containing 1% cholesterol and 1% OGT, the KBG group was fed standard rabbit chow containing 1% cholesterol an...

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Section: Fig 1 Effects Of Kampo Medicines On Progression Of Atheromcontrasting

confidence: 65%

Oren-gedoku-to and Keishi-bukuryo-gan-ryo Inhibit the Progression of Atherosclerosis in Diet-Induced Hypercholesterolemic Rabbits

Sekiya

Kainuma

Hikiami

et al. 2005

Biological & Pharmaceutical Bulletin

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“…Subsequent studies have revealed similar properties in other common antioxidants, including flavonoids [30], nonflavonoid phenols [36], cysteine [37,38], and urate [39][40][41]. The effects of ascorbate are further complicated by the fact that dehydroascorbate, the product of its two-electron oxidation, can itself act as both a pro-oxidant and an antioxidant toward LDL [24,26,35,42].…”

Section: Introductionmentioning

confidence: 99%

“…Due to the epidemiological evidence indicating an inverse relationship between dietary fruit and vegetable intake and the incidence of cardiovascular disease [20,21], numerous studies have been undertaken to show that micronutrients provided by such diets, including α-tocopherol [22,23], ascorbic acid [24][25][26][27] and various flavonoids [28][29][30][31], can protect LDL from oxidative modification [32]. Under certain circumstances, however, they have been shown to display prooxidant activity.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of the antioxidant to pro-oxidant switch in the behavior of dehydroascorbate during LDL oxidation by copper(II) ions

Horsley

Burkitt

Jones

et al. 2007

Archives of Biochemistry and Biophysics

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Subject area: Systems biochemistryAbbreviations: BCDS, bathocuproine disulphonic acid; DMPO,5, EPR, electron paramagnetic resonance; 13-HPODE, 13(S)-hydroperoxyoctadeca-9Z,11E-dienoic acid 2 ABSTRACTOxidised low density lipoprotein (LDL) may be involved in the pathogenesis of atherosclerosis.We have therefore investigated the mechanisms underlying the antioxidant/pro-oxidant behavior of dehydroascorbate, the oxidation product of ascorbic acid, toward LDL incubated with Cu 2+ ions. By monitoring lipid peroxidation through the formation of conjugated dienes and lipid hydroperoxides, we show that the pro-oxidant activity of dehydroascorbate is critically dependent on the presence of lipid hydroperoxides, which accumulate during the early stages of oxidation.Using electron paramagnetic resonance spectroscopy, we show that dehydroascorbate amplifies the generation of alkoxyl radicals during the interaction of copper ions with the model alkyl hydroperoxide, tert-butylhydroperoxide. Under continuous-flow conditions, a prominent doublet signal was detected, which we attribute to both the erythroascorbate and ascorbate free radicals.On this basis, we propose that the pro-oxidant activity of dehydroascorbate toward LDL is due to its known spontaneous interconversion to erythroascorbate and ascorbate, which reduce Cu 2+ to Cu + and thereby promote the decomposition of lipid hydroperoxides. Various mechanisms, including copper chelation and Cu + oxidation, are suggested to underlie the antioxidant behavior of dehydroascorbate in LDL that is essentially free of lipid hydroperoxides.

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“…These catechins have strong antioxidant activity (Rice-Evans, 1999;Dufresne and Farnworth, 2001;Higdon and Frei, 2003); they are potent scavengers of reactive oxygen species (ROS) such as superoxide, hydrogen peroxide, hydroxyl radicals and nitric oxide produced by various chemicals (Guo et al, 1996;Vinson et al, 2002;Schroeder et al, 2003). It has been demonstrated that EGCG prevents spontaneous mutations (Mure and Rossman, 2001), LDL oxidation (Yamanaka et al, 1997) and chromosomal damage induced by ROS in somatic cells (Sugisawa and Umegaki, 2002;Roy et al, 2003). Sugisawa and Umegaki (2002) reported that a large amount of EGCG was present in cells after they were incubated with 0.3 µM EGCG.…”

Section: Introductionmentioning

confidence: 99%

Effects of epigallocatechin-3-gallate on the developmental competence of parthenogenetic embryos in the pig

Yavari

Naoi

Kaedei

et al. 2010

Italian Journal of Animal Science

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This study was conducted to examine the effects of (-)-epigallocatechin gallate (EGCG) supplementation on the developmental competence and quality of parthenogenetic porcine embryos during culture. Parthenogenetic embryos derived from in vitro matured oocytes were cultured for eight days in a modified North Carolina State University (NCSU)-37 solution supplemented with EGCG at different concentrations (0, 1, 5, 10 and 50 µM). Supplementation of 1 and 5 µM EGCG during in vitro culture of embryos showed no significant influence on the rate of cleavage or that of blastocyst formation or on the total cell number and DNA fragmentation indices of blastocysts when compared to those of a control group. However, when 10 and 50 µM EGCG were supplemented into the culture medium, the cleavage rates were significantly lower than those of the other groups. No embryo developed to the blastocyst stage. Results suggest that treatment with low EGCG during in vitro culture has no influence on the developmental competence of porcine embryos but the presence of high concentrations of EGCG is apparently harmful for in vitro development of porcine parthenotes.

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Green tea catechins such as (−)‐epicatechin and (−)‐epigallocatechin accelerate Cu²⁺‐induced low density lipoprotein oxidation in propagation phase

Abstract: Effects of (-)-epicatechin (EC) and (-)-epigallocatechin (EGC) on Cu

Cited by 112 publications

References 19 publications

Oren-gedoku-to and Keishi-bukuryo-gan-ryo Inhibit the Progression of Atherosclerosis in Diet-Induced Hypercholesterolemic Rabbits

Oren-gedoku-to and Keishi-bukuryo-gan-ryo Inhibit the Progression of Atherosclerosis in Diet-Induced Hypercholesterolemic Rabbits

Mechanism of the antioxidant to pro-oxidant switch in the behavior of dehydroascorbate during LDL oxidation by copper(II) ions

Effects of epigallocatechin-3-gallate on the developmental competence of parthenogenetic embryos in the pig

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Green tea catechins such as (−)‐epicatechin and (−)‐epigallocatechin accelerate Cu2+‐induced low density lipoprotein oxidation in propagation phase

Abstract: Effects of (-)-epicatechin (EC) and (-)-epigallocatechin (EGC) on Cu

Cited by 112 publications

References 19 publications

Oren-gedoku-to and Keishi-bukuryo-gan-ryo Inhibit the Progression of Atherosclerosis in Diet-Induced Hypercholesterolemic Rabbits

Oren-gedoku-to and Keishi-bukuryo-gan-ryo Inhibit the Progression of Atherosclerosis in Diet-Induced Hypercholesterolemic Rabbits

Mechanism of the antioxidant to pro-oxidant switch in the behavior of dehydroascorbate during LDL oxidation by copper(II) ions

Effects of epigallocatechin-3-gallate on the developmental competence of parthenogenetic embryos in the pig

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Green tea catechins such as (−)‐epicatechin and (−)‐epigallocatechin accelerate Cu²⁺‐induced low density lipoprotein oxidation in propagation phase