Green tea extract only affects markers of oxidative status postprandially: lasting antioxidant effect of flavonoid-free diet

Epidemiological studies suggest that foods rich in flavonoids might reduce the risk of cardiovascular disease and cancer. The objective of the present study was to investigate the effect of green tea extract (GTE) used as a food antioxidant on markers of oxidative status after dietary depletion of flavonoids and catechins. The study was designed as a 2×3 weeks blinded human cross-over intervention study (eight smokers, eight non-smokers) with GTE corresponding to a daily intake of 18·6 mg catechins/d. The GTE was incorporated into meat patties and consumed with a strictly controlled diet otherwise low in flavonoids. GTE intervention increased plasma antioxidant capacity from 1·35 to 1·56 (P<0·02) in postprandially collected plasma, most prominently in smokers. The intervention did not significantly affect markers in fasting blood samples, including plasma or haemoglobin protein oxidation, plasma oxidation lagtime, or activities of the erythrocyte superoxide dismutase, glutathione peroxidase, glutathione reductase and catalase. Neither were fasting plasma triacylglycerol, cholesterol, α-tocopherol, retinol, β-carotene, or ascorbic acid affected by intervention. Urinary 8-oxo-deoxyguanosine excretion was also unaffected. Catechins from the extract were excreted into urine with a half-life of less than 2 h in accordance with the short-term effects on plasma antioxidant capacity. Since no long-term effects of GTE were observed, the study essentially served as a fruit and vegetables depletion study. The overall effect of the 10-week period without dietary fruits and vegetables was a decrease in oxidative damage to DNA, blood proteins, and plasma lipids, concomitantly with marked changes in antioxidative defence.

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Color Properties and Antioxidant Capacity of Purple Sweet Potato (Ipomoea batatas L) Anthocyanin Co-pigmented with Green Tea Extract

Current Advances in Chemistry and Biochemistry Vol. 2 ◽

10.9734/bpi/cacb/v2/7316d ◽

2021 ◽

pp. 76-82

Author(s):

Retno Yunilawati ◽

. Yemirta

Keyword(s):

Antioxidant Capacity ◽

Sweet Potato ◽

Green Tea ◽

Ipomoea Batatas ◽

Green Tea Extract ◽

Color Properties ◽

Purple Sweet Potato ◽

Tea Extract

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Timescale and colony-dependent relationships between environmental conditions and plasma oxidative markers in a long-lived bat species

Conservation Physiology ◽

10.1093/conphys/coaa083 ◽

2020 ◽

Vol 8 (1) ◽

Author(s):

Michaël Beaulieu ◽

Frédéric Touzalin ◽

Serena E Dool ◽

Emma C Teeling ◽

Sébastien J Puechmaille

Keyword(s):

Antioxidant Capacity ◽

Environmental Conditions ◽

Annual Variation ◽

Oxidative Status ◽

Conservation Physiology ◽

Temperature Anomalies ◽

Oxidative Markers ◽

Habitat Variation ◽

Plasma Antioxidant Capacity ◽

Plasma Antioxidant

Abstract To increase the applicability and success of physiological approaches in conservation plans, conservation physiology should be based on ecologically relevant relationships between physiological markers and environmental variation that can only be obtained from wild populations. Given their integrative and multifaceted aspects, markers of oxidative status have recently been considered in conservation physiology, but still need to be validated across environmental conditions and locations. Here, we examined whether inter-annual variation in two oxidative markers, plasma antioxidant capacity and plasma hydroperoxides, followed inter-annual variation in temperature anomalies and associated vegetation changes in four colonies of long-lived greater mouse-eared bats (Myotis myotis) monitored over five consecutive years. We found that the plasma antioxidant capacity of bats decreased while plasma hydroperoxide concentrations increased with increasing temperature anomalies occurring in the two weeks before blood sampling. Moreover, the antioxidant defences of these bats reflected vegetation indices, which themselves reflected the thermal conditions experienced by bats in their foraging habitat. Variation in oxidative markers therefore appears to be due to variation in thermoregulatory costs and to indirect changes in foraging costs. Overall, these results validate the use of markers of oxidative status in conservation physiology to monitor thermal perturbations recently experienced by animals in their natural habitat. However, even though oxidative markers varied in the same direction in all four bat colonies across years, the amplitude of their response differed. If these different physiological responses reflect different performances (e.g. productivity, survival rate) between colonies, this implies that, if necessary, conservation measures may need to be applied at the local scale.

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Green tea extract to prevent colorectal adenomas in men and women: Results of the MIRACLE trial.

Journal of Clinical Oncology ◽

10.1200/jco.2020.38.15_suppl.1551 ◽

2020 ◽

Vol 38 (15_suppl) ◽

pp. 1551-1551

Author(s):

Thomas Jens Ettrich ◽

Julia Stingl ◽

Stefan Menzler ◽

Helmut Messmann ◽

Gerhard Kleber ◽

...

Keyword(s):

Green Tea ◽

Statistical Significance ◽

Daily Intake ◽

Multicenter Trial ◽

Green Tea Extract ◽

Colorectal Adenomas ◽

Male Population ◽

Female Population ◽

Tea Extract

1551 Background: Prevention of colorectal adenomas (CA) can reduce colorectal cancers (CRC). Epidemiological and experimental data suggest that the green tea catechin epigallocatechingallate has an antineoplastic effect in the large bowel. MIRACLE is the largest trial so far to examine the effect of three-year daily intake of green tea extract (GTE) on the incidence of metachronous CA in a Caucasian population. Methods: Prospective, parallel group, double-blinded, placebo-controlled, randomized multicenter trial (40 German centers, recruitment 11/2011-6/2015). Patients (n = 1001, age 50-80y), polypectomy ≤ 6 months and tolerating GTE well (one-month run-in) were randomized to receive decaffeinated GTE standardized to EGCG (150 mg bid, capsules) or placebo (P) for 3 years. Primary endpoint: Incidence of metachronous CA at the 3-year follow-up colonoscopy. Secondary endpoints: Occurrence, number, localization, size, histological subtype of CA, frequency of CRC, biomarker and safety. Strata: study center, low-dose aspirin (≤100 mg/d). Results: Clinical parameters were well balanced. CA incidence at the 3-year follow-up colonoscopy was analyzed in the modified ITT set (modITT; n = 309 patients (GTE), n = 323 (placebo), timely follow up colonoscopy) and the per protocol set (PP, modITT set without major protocol violations). Incidence of CA was 55.7 % (P) and 51.1% (GTE), (modITT, adj. RR 0.905, one sided, p = 0.081), respectively 54.3 % (P) and 48.3% (GTE) (PP, adj. RR 0.883, one sided, p = 0.058). These differences did not reach statistical significance. In the preplanned exploratory analysis regarding gender incidence of CA in females was 47.9% (P) and 47.6% (GTE) in the modITT-set (adj. RR 0.989; 95%-CI: 0.753,1.299; p = 0.935), respectively 45.4% (P) and 46.9% (GTE) in the PP-set (adj. RR 1.014; 95%-CI: 0.748, 1.373; p = 0.930). In contrast, in the male population incidence of CA in the follow-up colonoscopy was 60.4% (P) and 52.9% (GTE) in the modITT-set (adj. RR 0.846; 95% CI 0.717, 0.999); p = 0.048), respectively 59.1% (P) and 49.1% (GTE) in the PP-set (RR 0.803, 95% CI: 0.666, 0.969; p = 0.022). Thus, GTE intake was associated with a significant, 12.4 relative and 7.5% absolute reduction of metachronous CA in the male modITT population. There were no differences with respect to safety between the groups. Conclusions: GTE reduced the incidence of metachronous CA. However, a significant effect was only observed in the in the male population whereas there was no effect in the female population. Clinical trial information: NCT 01360320.

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Abstract P423: Effects of Green Tea and Soy Isoflavones on Plasma Lipids In Healthy Subjects

Circulation ◽

10.1161/circ.129.suppl_1.p423 ◽

2014 ◽

Vol 129 (suppl_1) ◽

Author(s):

Miao Hu ◽

Elaine Wat ◽

Clara Lau ◽

Brian Tomlinson

Keyword(s):

Blood Pressure ◽

Green Tea ◽

Plasma Lipids ◽

Density Lipoprotein ◽

Green Tea Extract ◽

Soy Isoflavones ◽

Lipoprotein Cholesterol ◽

Once Daily ◽

Tea Extract ◽

Male Subjects

Introduction: Green tea and soy products are widely consumed in daily life and are considered to have beneficial effects on reducing cardiovascular risks. The flavonoids present in soya bean and tea leaves are believed to be responsible for the proposed benefits. Hypothesis: We assessed the hypothesis that epigallocatechin gallate (EGCG), the most abundant active component of green tea and soy isoflavonoids may reduce the plasma lipid levels in healthy volunteers. Methods: Healthy Chinese male subjects were given green tea extract containing EGCG 800 mg once daily for 14 days and soy isoflavones extract 80 mg once daily for 14 days with a wash-out of at least 4-weeks between the two treatments. Sitting blood pressure and fasting plasma lipids were measured at baseline, after green tea and after soy isoflavones, respectively. Results: In 18 healthy male subjects (mean age 26.6 ± 6.0 years, weight 61.7 ± 6.3 kg), consumption of green tea extract, but not soy isoflavones, was associated with significant reductions in plasma low-density lipoprotein cholesterol (LDL-C) (8.1% [95% confidence interval: -2.0, -14.3%], P<0.01) and total cholesterol (4.8 % [0.4,-10.1%], P<0.05) compared to baseline (Table 1). Reduction in LDL-C with green tea was observed in 15 out of 18 subjects and the change in LDL-C was not affected by the baseline levels. Neither product influenced the plasma high-density lipoprotein cholesterol (HDL-C) or triglyceride levels or blood pressure in this normotensive group of subjects (Table 1). Conclusion: This study showed that short term treatment with a high dose of green tea extract, which is equivalent to about 7-10 cups of green tea, reduced plasma LDL-C which may be beneficial for reducing cardiovascular risk.

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