Tea polyphenols benefit vascular function

Yung, Lai Ming; Leung, Fung Ping; Wong, Wing Tak; Tian, Xiaoyu; Chen, Z. Y.; Yao, Xiaoqiang; Huang, Yü

doi:10.1007/s10787-008-8022-y

Cited by 57 publications

(44 citation statements)

References 37 publications

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“…Moreover, it is well known that catechins constitute the major class of bioactive substances in tea. The association between tea consumption and blood pressure reduction has also been positively verified in experimental models, and the effect was considered mainly due to the favorable modification of the expression and function of oxidant and antioxidant enzymes (26). Hence, the results in this study not only indicated an additional potential pathway for the role of catechins in lowering blood pressure, but also provided evidence supporting tea consumption as an approach to helping control hypertension.…”

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confidence: 66%

Inhibitory effect of catechin-related compounds on renin activity

Takahashi

Yamaki

2013

Biomed. Res.

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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 catechinrelated compounds on renin was investigated in this work. It was found that epigallocatechin gallate (EGCg) possessed the strongest activity with an IC 50 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.Hypertension is significantly associated with the incidence of various cardiovascular diseases. The renin-angiotensin system (RAS) plays an important role in regulating blood pressure in animals, and its inhibition has been well established as an approach to the treatment of hypertension (15). In this system, renin (EC 3.4.23.15) and angiotensin I-converting enzyme (ACE; EC 3.4.15.1) are two key enzymes. Renin can cleave the N-terminus of angiotensinogen to yield angiotensin I, which is an inactive peptide and may further be processed by ACE to produce angiotensin II, a potent vasoconstrictor. Since the conversion catalyzed by renin is the rate-limiting step, it is thought that direct renin inhibition could lead to better suppression of high blood pressure than ACE inhibition can (2). Although many ACE inhibitors derived from foodstuffs have been identified in the past (7), only a few reports on natural renin inhibitors were available (6,11,20,21). Studies have supported that polyphenol-containing materials such as black and green tea (14), red wine (12), cocoa extract (5, 17) and azuki bean seed coats (13) could reduce blood pressure in several experimental hypertensive models. The mechanisms underlying this effect were proposed to be attributable to vasodilator action, the attenuation of vascular oxidative stress and inflammation, and the ability to reduce arginase-2 activity (18), as well as the inhibitory effect against ACE (1, 3). Nevertheless, to date, not much attention has been paid to their potential renin-inhibitory activities. Recently, researchers found that saponins (8, 20, 21), baicalin (6), and the polyphenolic extracts of two green leafy vegetables (2) showed renin-inhibitory activities, which thus suggested the promising prospect of discovering polyphenolic compounds as candidates for renin inhibitors. Catechins represent a major class of polyphenols and are widely distributed in plants. There are four principal kinds of catechins, that is, epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate; the beneficial effects of these compounds on health have been continually studied (4, 10). In the present work, we investigated whether catechin-related compounds could exert renin-inhibitory activities in vitro and also primarily elucidated their structure-act...

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confidence: 66%

Inhibitory effect of catechin-related compounds on renin activity

Takahashi

Yamaki

2013

Biomed. Res.

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“…In fact, the intravenous administration of low doses of isoquercitrin (but not kaempferol) administration was able to cause a significant drop in the mean arterial pressure of anesthetized rats (∼25 mm Hg), remembering the effect of HETM and TMLR in blood pressure. Several flavonoids have been shown as cardioprotective and hypotensive agents in animal models (Jadhav et al, 2010;Pechanova et al, 2006;Wright et al, 2007;Yung et al, 2008). Isoquercitrin or plants containing high amounts of this flavonol are described as able to stabilize atherosclerotic plaques (Enkhmaa (Kim et al, 2007;Silva et al, 2009;Vitor et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

Antihypertensive effects of isoquercitrin and extracts from Tropaeolum majus L.: Evidence for the inhibition of angiotensin converting enzyme

Gasparotto

Lourenço

Crestani

et al. 2011

Journal of Ethnopharmacology

136

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“…Tea polyphenols are an important group of natural compounds that have gained popularity as ingredients in dietary supplements and functional foods. Tea polyphenols have also been reported to possess a variety of biological properties that have positive impact on human health [1][2][3], which includes anti-inflammatory, anti-obesity effects and reduced risk of cardiovascular diseases and cancer [4][5][6][7][8]. Green, black and oolong teas are rich sources of polyphenols, the most abundant being catechins and theaflavins.…”

Section: Introductionmentioning

confidence: 99%