PMID: 

Nutrients. 2018 Aug 20 ;10(8). Epub 2018 Aug 20. PMID: 30127247

Abstract Title: 

Acute Epigallocatechin 3 Gallate (EGCG) Supplementation Delays Gastric Emptying in Healthy Women: A Randomized, Double-Blind, Placebo-Controlled Crossover Study.

Abstract: 

: Epigallocatechin 3 Gallate (EGCG) appears to act in appetite control through hormonal modulation. However, there is a lack of elucidation of EGCG's action mechanisms, especially in humans. The aim of this study was to evaluate the effects of acute EGCG supplementation on gastric emptying and its relation to blood hormones, glucose and appetite perceptions in healthy women.: 22 healthy adult women were included in a randomized, double-blind, placebo-controlled crossover study. On two separate occasions, 1 week apart from each other, we offered 800 mg of corn starch (placebo) or 752 mg of EGCG. Appetite was assessed through gastric emptying; perceptions of hunger, desire to eat and satiation; and plasma insulin, adiponectin, leptin and glucose concentrations. The evaluations were carried out in fasting, 30, 90 and 150 min after supplementation.: EGCG supplementation induced higher relative gastric volume at 30 and 90 min. Satiation at 90 min was higher in the EGCG group. Adiponectin concentrations at 150 min were higher with EGCG, but no difference was found for glucose, insulin and leptin concentrations.: Acute EGCG supplementation is able to delay gastric emptying in healthy women to a small, but statistically significant extent. This study was registered at the Brazilian Registry of Clinical Trials (ReBEC) as RBR-9svwrv.

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PMID: 

Nephrol Dial Transplant. 2011 Apr ;26(4):1188-93. Epub 2010 Oct 14. PMID: 20947539

Abstract Title: 

Renoprotective effects of green tea extract on renin-angiotensin-aldosterone system in chronic cyclosporine-treated rats.

Abstract: 

BACKGROUND: Renin-angiotensin-aldosterone system (RAAS) activation plays an important role in cyclosporine (CsA)-induced nephropathy. The main aim of this study was to test whether the administration of green tea extract (GTE) prevents the development of CsA-induced nephrotoxicity.METHODS: The rats were treated for 21 days and divided into four groups (n = 6/group): control group (0.9% saline injection), CsA group (30 mg/kg/day by intraperitoneal injection), CsA-GTE group (CsA plus GTE 100 mg/kg/day subcutaneous injection) and GTE group (GTE alone).RESULTS: There were significant increased levels of serum blood urea nitrogen and creatinine in the CsA group compared with that of the control group and significantly improved in the CsA-GTE group. Biochemical analysis showed that the plasma renin activity (PRA) and serum concentration of aldosterone were significantly increased in the CsA group compared with the control group and significantly decreased in the CsA-GTE group compared with the CsA group. The total level of renin protein expression was significantly higher in the CsA group than in the control group, and it was lower in the CsA-GTE group than in the CsA group.CONCLUSIONS: CsA treatment increases the PRA and intrarenal renin levels and induces nephrotoxicity. The protective effects of GTE on CsA-induced structural and functional alternations of the kidney may be the blockage of RAAS.

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PMID: 

Biomed Res. 2013 Jun ;34(3):167-71. PMID: 23782751

Abstract Title: 

Inhibitory effect of catechin-related compounds on renin activity.

Abstract: 

Renin is a crucial enzyme in the renin-angiotensin system, and the inhibition of its activity is considered as a useful approach to the treatment of hypertension. The inhibitory effect of catechin-related compounds on renin was investigated in this work. It was found that epigallocatechin gallate (EGCg) possessed the strongest activity with an IC₅₀ value of 44.53 μM and acted in an uncompetitive manner. Gallated catechins exerted higher inhibition than the ungallated forms, and gallic acid exhibited an inhibitory potency close to that of epicatechin gallate (ECg). Results indicated that the galloyl moiety and ortho-trihydroxy phenyl structures might be favorable for the renin-inhibitory activity of these compounds.

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PMID: 

J Agric Food Chem. 2013 Oct 9 ;61(40):9697-704. Epub 2013 Sep 30. PMID: 24028635

Abstract Title: 

Tea polyphenols as novel and potent inhibitory substances against renin activity.

Abstract: 

Renin inhibitory activities of three tea products were investigated for the first time in this work. Water extracts from fermented oolong and black tea showed strong renin inhibitory activities. By the means of ultrafiltration, gradient high performance liquid chromatography and spectroscopic analysis, four active compounds were separated from aqueous black tea extract and identified as theasinensin B, theasinensin C, strictinin, and a hexose sulfate with a galloyl moiety, which had IC50 values of 19.33, 40.21, 311.09, and 50.16μM against renin activity, respectively. Further detection indicated that the potent inhibitor theasinensin B was present only in black tea, and that monomeric catechins did not contribute significantly to the renin inhibitory activities of tea products. These results revealed novel and potent tea-derived renin inhibitors and suggested another potential pathway for tea consumption to control hypertension.

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PMID: 

Food Funct. 2015 Sep ;6(9):2957-66. PMID: 26234931

Abstract Title: 

The acute impact of polyphenols from Hibiscus sabdariffa in metabolic homeostasis: an approach combining metabolomics and gene-expression analyses.

Abstract: 

We explored the acute multifunctional effects of polyphenols from Hibiscus sabdariffa in humans to assess possible consequences on the host's health. The expected dynamic response was studied using a combination of transcriptomics and metabolomics to integrate specific functional pathways through network-based methods and to generate hypotheses established by acute metabolic effects and/or modifications in the expression of relevant genes. Data were obtained from healthy male volunteers after 3 hours of ingestion of an aqueous Hibiscus sabdariffa extract. The data were compared with data obtained prior to the ingestion, and the overall findings suggest that these particular polyphenols had a simultaneous role in mitochondrial function, energy homeostasis and protection of the cardiovascular system. These findings suggest beneficial actions in inflammation, endothelial dysfunction, and oxidation, which are interrelated mechanisms. Among other effects, the activation of the heme oxygenase-biliverdin reductase axis, the systemic inhibition of the renin-angiotensin system, the inhibition of the angiotensin-converting enzyme, and several actions mirroring those of the peroxisome proliferator-activated receptor agonists further support this notion. We also found concordant findings in the serum of the participants, which include a decrease in cortisol levels and a significant increase in the active vasodilator metabolite of bradykinin (des-Arg(9)-bradykinin). Therefore, our data support the view that polyphenols from Hibiscus sabdariffa play a regulatory role in metabolic health and in the maintenance of blood pressure, thus implying a multi-faceted impact in metabolic and cardiovascular diseases.

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PMID: 

Atherosclerosis. 2018 03 ;270:123-131. Epub 2018 Feb 2. PMID: 29407880

Abstract Title: 

The protective effect of resveratrol on vascular aging by modulation of the renin-angiotensin system.

Abstract: 

BACKGROUND AND AIMS: This study evaluated the effects of resveratrol on arterial aging and the renin-angiotensin system (RAS) in mice and vascular smooth muscle cells (VSMCs).METHODS: Aging mice were divided into control and resveratrol groups. Histological changes, inflammation, oxidative stress, RAS components, and the expression of AMP-activated protein kinase (AMPK), silent information regulator T1 (SIRT1), peroxisome proliferator-activated receptor-γ co-activator 1α (PGC-1α), and anti-oxidative enzymes was measured in thoracic aortas of 24-month-old mice. The effect of resveratrol on fibrosis, cell senescence, and RAS components was also investigated in VSMCs stimulated by angiotensin (Ang) II.RESULTS: Aorta media thickness, inflammation, fibrosis, and oxidative stress were significantly lower in the resveratrol group than in the control group. Resveratrol treatment decreased serum Ang II level and the aortic expression of prorenin receptor (PRR) and angiotensin converting enzyme (ACE), and increased serum Ang-(1-7) level and the expression of ACE2, Ang II type 2 receptor (AT2R), and Mas receptor (MasR). Resveratrol increased the expression of phosphorylated AMPK, SIRT1, PGC-1α, phosphorylated endothelial nitric oxide synthase and superoxide dismutase 1 and 2, and decreased that of NADPH oxidase 2 and 4. In Ang II-stimulated VSMCs, resveratrol treatment markedly decreased the number of senescence associated β-galactosidase stained cells and pro-fibrotic protein expression and increased the expression of AT2R and MasR.CONCLUSIONS: Resveratrol protects against arterial aging and this effect is associated with reduced activity of the PRR-ACE-Ang II axis and stimulation of the ACE2-Ang-(1-7)-ATR2-MasR axis.

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PMID: 

Nutrients. 2019 Nov 14 ;11(11). Epub 2019 Nov 14. PMID: 31739443

Abstract Title: 

Effects of Phytochemicals on Blood Pressure and Neuroprotection Mediated Via Brain Renin-Angiotensin System.

Abstract: 

BACKGROUND: The renin-angiotensin system (RAS) in the brain plays a crucial role in maintaining blood pressure as well as neuroprotection. This study compared the effects of curcumin, quercetin, and saponin on blood pressure, the brain RAS, and cholinergic system using perindopril, an angiotensin converting enzyme inhibitor (ACEI), as a positive control.METHODS: Five-week-old male mice were stabilized and randomly assigned into a control group (= 8), three phytochemical-treated groups (curcumin (= 8), quercetin (= 8), and saponin (= 8)), and a positive control group (= 8). The groups treated with the phytochemical were orally administered daily at a dose of 50 mg/kg body weight of phytochemicals. During the experiments, the weight and dietary intakes were measured regularly. After experiments, the brain tissue was homogenized and centrifuged for an additional assay. The concentrations of ACE, angiotensin II (AngII), and aldosterone levels were measured, and the mRNA expressions of renin and ACE were measured. As biomarkers of neuroprotection, the concentrations of acetylcholine(Ach) as well as the concentration and activity of acetylcholine esterase (AChE) were measured.RESULTS: After 4 weeks of treatment, the perindopril group showed the lowest blood pressure. Among the groups treated with the phytochemicals, treatment with curcumin and saponin significantly reduced blood pressure, although such effect was not as high as that of perindopril. Among phytochemicals, curcumin treatment significantly inhibited the concentration and activity of ACE, concentration of AngII, and mRNA expression of ACE. All phytochemical treatments significantly increased the concentration of ACh. The levels of AChE activity in groups exposed to curcumin or saponin (not quercetin) were significantly inhibited, Conclusion: Curcumin administration in rats reduced blood pressure by blocking the brain RAS components and protected the cholinergic system in brain by inhibiting the activity of AChE.

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PMID: 

Nutrients. 2018 Dec 27 ;11(1). Epub 2018 Dec 27. PMID: 30591664

Abstract Title: 

Effects of Coffee and Tea Consumption on Glucose Metabolism: A Systematic Review and Network Meta-Analysis.

Abstract: 

Prospective cohort studies have described an association between coffee or tea consumption and the risk of developing diabetes. However, whether coffee or tea improves glucose metabolism remains uncertain. We investigated the effect of coffee and tea on glucose metabolism by conducting a systematic review and meta-analysis of randomized controlled trials. Electronic databases were searched for articles published up 19 February 2017. The primary endpoint was the mean difference in post-intervention fasting blood glucose (FBG) levels between the groups. Of 892 citations screened, 27 studies (1898 participants) were included in our meta-analysis. A network meta-analysis suggested that green tea, but not caffeinated/decaffeinated coffee or black tea, may reduce FBG levels, compared with placebo/water (-2.10 mg/dL; 95% confidence interval (CI), -3.96 to -0.24 mg/dL;= 0.03; moderate quality of evidence). In a subgroup analysis, the effect of green tea on FBG levels was statistically significant only in studies with a mean age of

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PMID: 

Molecules. 2019 May 19 ;24(10). Epub 2019 May 19. PMID: 31109117

Abstract Title: 

Neuroprotective and Anti-Amyloidβ Effect and Main Chemical Profiles of White Tea: Comparison Against Green, Oolong and Black Tea.

Abstract: 

White tea (WT) is one of six tea types originally derived from Fujian Province, China. White tea is known for its health-promoting properties. However, the neuroprotective and anti-aggregatory properties of WT against the hallmark toxic Alzheimer's protein, Aβ have not been investigated. In this study, WT, green tea (GT), oolong tea (OT) and black tea (BT) were manufactured using tea leaves from the cultivar(Jin Guanyin). The protective effects of these tea extracts were then studied under oxidative stress conditions via-bhp and HOexposure, in addition to Aβ treatment using a PC-12 cell model. Each tea type failed to rescue PC-12 cells from either-bhp or HO-mediated toxicity, however each extract exerted significant protection against Aβ-evoked neurotoxicity. Results of the Thioflavin T Kinetic (ThT) and TEM assay showed that Aβ aggregate formation was inhibited by each tea type. Additionally, TEM also supported the different anti-aggregatory effect of WT by modifying Aβ into an amorphous and punctate aggregate morphology. Higher accumulated precedent or potential neuroprotective compounds in WT, including ECG''3Me, 8–ascorbyl-EGCG, GABA and Gln, in addition to flavonol or flavone glycosides detected by using UPLC-QTOF-MS and UPLC-QqQ-MS, may contribute to a favourable anti-aggregative and neuroprotective effect of WT against Aβ.

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PMID: 

J Agric Food Chem. 2019 Jul 17 ;67(28):7869-7879. Epub 2019 Jul 9. PMID: 31287296

Abstract Title: 

Oolong Tea Extract and Citrus Peel Polymethoxyflavones Reduce Transformation of l-Carnitine to Trimethylamine–Oxide and Decrease Vascular Inflammation in l-Carnitine Feeding Mice.

Abstract: 

Carnitine, a dietary quaternary amine mainly from red meat, is metabolized to trimethylamine (TMA) by gut microbiota and subsequently oxidized to trimethylamine–oxide (TMAO) by host hepatic enzymes, flavin monooxygenases (FMOs). The objective of this study aims to investigate the effects of flavonoids from oolong tea and citrus peels on reducing TMAO formation and protecting vascular inflammation in carnitine-feeding mice. The results showed that mice treated with 1.3% carnitine in drinking water significantly (

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