Antihypertensive properties of flavonoid-rich apple peel extract

Balasuriya, Nileeka; Rupasinghe, H.P. Vasantha

doi:10.1016/j.foodchem.2012.07.023

Cited by 146 publications

(98 citation statements)

References 25 publications

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“…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.…”

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confidence: 99%

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: 99%

Inhibitory effect of catechin-related compounds on renin activity

Takahashi

Yamaki

2013

Biomed. Res.

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“…The objective of the current preclinical study was to evaluate the potential to use APE as a natural antihypertensive agent using a rodent model. APE is a rich source of polyphenols, primarily flavanols, flavan-3-ols, dihydrochalcones and chlorogenic acid 5 . These groups of phytochemicals are well documented for their function as antioxidants, enzyme inhibitors and cell signaling pathway modulators 17 .…”

Section: Discussionmentioning

confidence: 99%

“…APE was found to be an effective ACE inhibitor under in vitro conditions 5 . Therefore, the effect of APE on the ACE activity of blood plasma and lung extracts on SHR was determined using a fluorimetric method.…”

Section: Discussionmentioning

confidence: 99%

“…The ACE activity of lung and plasma samples was determined as described previously 5,16 . Heparin, histidine-L-hippuryl-L-leucinechloride (HHL), NaOH, HCl, ethanol anhydrous and o-phthalaldehyde were purchased from Sigma Aldrich Canada Ltd. (Oakville, ON, Canada).…”

Section: Determination Of Ace Activitymentioning

confidence: 99%

“…One such example is over expression of ACE producing genes leading to high levels of ACE. Flavonoids were reported as ACE inhibitors both in vitro 5 and in vivo 6 . It is become evident that oxidative stress in the arterial walls and kidneys also plays a role in the development and progression of hypertension, with antioxidant systems such as superoxide dismutase (SOD) and glutathione being down-regulated 7 .…”

Section: Introductionmentioning

confidence: 99%

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Antihypertensive Effects of Apple Peel Extract on Spontaneously Hypertensive Rats

Balasuriya¹,

Rupasinghe²,

Sweeney³

et al. 2015

Pharmacologia

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Background and Objectives:Apple peel is a rich source of biological active phytochemicals such as flavonoids. The present study investigated the antihypertensive effect of flavonoid-rich Apple Peel Extract (APE) on Spontaneously Hypertensive Rats (SHR). Methodology: Three groups of animals: Control, captopril (20 mg kgG 1 of body weight/day) and APE (25 mg kgG 1 of body weight/day) were fed standard rat chow and their corresponding treatment in sugar-free gelatin, daily for a period of eight weeks. Blood Pressure (BP) was monitored weekly using the tail cuff method. Blood and tissue samples were collected after the eighth week. Results: As expected, treatment with captopril consistently reduced BP (p<0.05). APE treatment reduced both systolic and diastolic BP by 15 and 11 mg Hg, respectively, after 5 weeks of treatment, However, statistical significance was only achieved in systolic BP after eight weeks when compared with control (p<0.05). There were no significant differences in serum and lung ACE activity at week eight. Treatment with APE increased liver superoxide dismutase (SOD) activity by 78% and total reduced Glutathione (GSH) concentrations by 42% when compared to control (p<0.05) but had no effect on the activity of glutathione reductase or peroxidase. Conclusion: Long term intake of APE reduces high blood pressure in SHR possibly through endogenous antioxidant pathways. This preclinical trial suggests that APE as a dietary supplement could be effective in managing early stages of hypertension.

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