Green tea polyphenols (flavan 3-ols) prevent oxidative modification of low density lipoproteins: an ex vivo study in humans

Miura, Yuri; Chiba, Tsuyoshi; Miura, Shinji; Tomita, Isao; Umegaki, Keizo; Ikeda, Masahiko; Tomita, Takako

doi:10.1016/s0955-2863(00)00068-1

Cited by 114 publications

(67 citation statements)

References 39 publications

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“…The antioxidant action of catechin epimers was observed not only in in vitro studies but also in ex vivo and in vivo studies [12,[26][27][28]. Since pH range of different human body fluids and tissues varies widely, from pH [12]; SC 50 concentration of catechins required to give a 50 % decrease in the signal intensity of DPPH Á radical; c [24], IC 50 concentration of catechins required to give a 50 % decrease in the lipid peroxidation assay; d [14]; e [25] 1.0-2.0 in the stomach, pH 5.7-6.5 in the duodenum, pH 5.5-7.0 in the colon, pH 5.9-6.8 in jejunum, pH 6.8 in esophagus, through pH 7.3-7.7 in ileum, pH 7.4 in blood and other body fluids to the pH 7.6-8.6 in pancreas [15,16], the effect of pH on the antioxidant properties of catechin epimers may be of biological relevance.…”

Section: Resultsmentioning

confidence: 99%

The influence of stereochemistry on the antioxidant properties of catechin epimers

Muzolf-Panek

Gliszczyńska‐Świgło

Szymusiak

et al. 2012

Eur Food Res Technol

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The influence of stereochemistry on the radical scavenging activity of catechins was investigated by studying the effect of pH on the antioxidant properties of catechin epimers. The difference in the pH-dependent Trolox equivalent antioxidant capacity (TEAC) profiles was observed only in case of gallocatechin gallate (GCG) and epigallocatechin gallate (EGCG), indicating the influence of steric structure on the TEAC antioxidant activity of these galloyl moiety-containing catechins. Based on comparison of the pH-dependent TEAC values to theoretically calculated parameters, including homolytic OH bond dissociation energy and ionization potential (IP) as well as theoretically predicted structures of the most stable monoanions of GCG and EGCG, it was concluded that due to steric hindrance in GCG molecule, the IP value of GCG monoanion increases reflecting lower radical scavenging capacity of GCG in comparison with EGCG. It results in the difference in the pH-dependent TEAC profiles of these two catechin epimers at pH above 3.5. This effect does not occur for other pairs of catechin epimers of this study.

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Section: Resultsmentioning

confidence: 99%

The influence of stereochemistry on the antioxidant properties of catechin epimers

Muzolf-Panek

Gliszczyńska‐Świgło

Szymusiak

et al. 2012

Eur Food Res Technol

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“…Green tea polyphenols have physiologic activities such as anticancer effects (Hara et al, 1989;Isemura et al, 1993;Muramatsu, 1994;Ito and Sasaki, 1995;Suganuma and Okabe, 1996;Dreosti et al, 1997;Imai et al, 1997), antioxidative activity (Kawase et al, 2000;Yokozawa et al, 2000), antibacterial effects (Sakanaka et al, 1989;Mabe et al, 1999;Amarowicz et al, 2000), antioxidative activity against low-density lipoprotein cholesterol (Rice-Evans et al, 1996;Miura et al, 2000), and reduction of blood cholesterol level (Muramatsu et al, 1986;Imai and Nakachi, 1995), body weight, body fat (Hase et al, 2001;Nagao et al, 2001;Tsuchida et al, 2002;Kajimoto et al, 2005), blood glucose level (Hara and Honda, 1990;Honda and Hara, 1993;Matsumoto et al, 1993) and suppression of postprandial triglyceride elevation (Unno et al, 2005). Therefore, it is expected that green tea polyphenols have preventive effects against lifestyle-related diseases.…”

Section: Introductionmentioning

confidence: 99%

Randomized controlled trial for an effect of green tea-extract powder supplementation on glucose abnormalities

et al. 2007

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Objective: We examined whether green tea-extract powder supplementation improves glucose abnormality. Methods: The study was conducted for volunteers who resided in eastern communities of Shizuoka Prefecture and who had fasting blood glucose levels of X6.1 mmol/l or nonfasting blood glucose levels of X7.8 mmol/l in a recent health check-up. Sixty subjects aged 32-73 years (49 males and 11 females) participated in the trial. The Early intervention group consumed a packet of green tea-extract powder containing 544 mg polyphenols (456 mg catechins) daily for the first 2 months and then entered the 2-month nonintervention period. The Later intervention group was observed for the first 2 months and then consumed green tea-extract powder as described above for the subsequent 2 months. Using the two-period crossover design, we analyzed the changes in fasting hemoglobin A1c level and other biomarkers in blood samples collected at baseline, 2 months and 4 months. Results: A significant reduction in hemoglobin A1c level and a borderline significant reduction in diastolic blood pressure were associated with the intervention. The intervention caused no significant changes in weight, body mass index, body fat, systolic blood pressure, fasting serum glucose level, homeostasis model assessment index, serum lipid level or hypersensitive C-reactive protein.Conclusion: Daily supplementary intake of green tea-extract powder lowered the hemoglobin A1c level in individuals with borderline diabetes.

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“…In oxidation mediated by ROS, LDL loses these endogenous lipophilic antioxidants (Esterbauer et al, 1987). In their study (Miura et al, 2000) they showed a prolonged lag time (14 min) of LDL oxidation in a group that consumed tea and thus suggested green tea to be capable of rendering LDL resistant to in-vivo oxidative damage and thus reducing the rate of cardiovascular diseases. Son (Son et al, 2004) reported the inhibition of rabbit platelet aggregation induced by collagens, arachidonic acid (AA), etc in-vitro and ex-vivo, by GTC.…”

Section: Cardiovascular Diseasesmentioning

confidence: 98%

“…antioxidative, anti-proliferative, anti-inflammatory, anti-platelet and anti-thrombotic activities, and the ability to affect lipid metabolism and vascular homeostasis (Velayutham et al, 2008). Miura (Miura et al, 2000), demonstrated green tea polyphenols increased α tocopherol and β carotene concentration, which are endogenous antioxidants in LDL. In oxidation mediated by ROS, LDL loses these endogenous lipophilic antioxidants (Esterbauer et al, 1987).…”

Section: Cardiovascular Diseasesmentioning

confidence: 99%

Role of tea catechins in prevention of aging and age-related disorders

Khanna¹,

Maurya²

2012

TANG [HUMANITAS MEDICINE]

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Tea polyphenols especially catechins have long been studied for their antioxidant and radical scavenging properties. Scientists throughout the world have investigated the usefulness of the regular green tea consumption in several disease conditions. In-vitro and in-vivo experiments on catechins especially epigallocatechingallate have revealed a significant role in many ways. Reactive oxygen species have been increasingly implicated in the pathogenesis of many diseases and important biological processes. Toxic effects of these oxidants, commonly referred to as oxidative stress, can cause cellular damage by oxidizing nucleic acids, proteins, and membrane lipids. Oxidative stress has been related to aging and age related disorders. It is found that in a wide variety of pathological processes, including cancer, atherosclerosis, neurological degeneration, Alzheimer's disease, ageing and autoimmune disorders, oxidative stress has its implications. Catechins have been reported to be useful in combating aging and age related disorders like cancer, cardiovascular disorders and neurodegenerative diseases. In this mini review we will discuss such studies done across the globe.

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Green tea polyphenols (flavan 3-ols) prevent oxidative modification of low density lipoproteins: an ex vivo study in humans

Cited by 114 publications

References 39 publications

The influence of stereochemistry on the antioxidant properties of catechin epimers

The influence of stereochemistry on the antioxidant properties of catechin epimers

Randomized controlled trial for an effect of green tea-extract powder supplementation on glucose abnormalities

Role of tea catechins in prevention of aging and age-related disorders

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