Dear Mohsen,

Polyphenols that are widespread antioxidants in vegetables and fruits in some studies have demonstrated their beneficial role in prevention and therapy of hypertension. Polyphenols inhibit ROS-producing enzymes such as NADPH and xanthine oxidases, activate, and enhance eNOS expression and increase glutathione. These have improved endothelial function, subsequent normalization of vascular tone, and an overall antihypertensive effect.

The antioxidants vitamins C and E and other antioxidants have been considered as possible therapy for decreasing oxidative stress and thereby lowering blood pressure. Additionally vitamins C and E down-regulate NADPH oxidase, a major source of ROS in the vascular wall, and up-regulate eNOS, both of these effects lower blood pressure. In this regard, a randomized double-blind clinical trial other than demonstrating a specific association between oxidative-stress-related parameters and blood pressure, documented enhancement of antioxidant status by supplementation with antioxidants vitamins C and E and their hypotensive properties.

Combination supplement with vitamin C, vitamin E, beta-carotene, and zinc also resulted in a significant reduction in systolic blood pressure and a nonsignificant reduction in diastolic blood pressure.

The diets rich in fruits and vegetables reduce blood pressure in hypertensive and normotensive patients. The modification in diet results in an increase in serum antioxidant capacity and a decrease in malondialdehyde, an in-vitro marker of lipid peroxidation, suggestive of a reduction in oxidative stress. In a study, increase of fruit and vegetable intake for a period of 6 months to the diet of hypertensive subjects, increased blood antioxidant capacity and decreased in systolic and diastolic blood pressure.

References:

Ward NC, Hodgson JM, Croft KD, Burke V, Beilin LJ, Puddey IB. The combination of vitamin C and grape-seed polyphenols increases blood pressure: A randomized, double-blind, placebo-controlled trial. J Hypertens. 2005;23:427–34. [PubMed]

Briones AM, Touyz RM. Oxidative stress and hypertension: Current concepts. Curr Hypertens Rep. 2010;12:135–42. [PubMed]

Rodrigo R, Prat H, Passalacqua W, Araya J, Bächler JP. Decrease in oxidative stress through supplementation of vitamins C and E is associated with a reduction in blood pressure in patients with essential hypertension. Clin Sci (Lond) 2008;114:625–34. [PubMed]

Ardalan MR, Rafieian-Kopaie M. Antioxidant supplementation in hypertension. J Renal Inj Prev. 2014;3:39–40. [PMC free article] [PubMed]

Tamadon MR, Baradaran A, Rafieian-Kopaei M. Antioxidant and kidney protection; differential impacts of single and whole natural antioxidants. J Renal Inj Prev. 2014;3:41–42. [PMC free article] [PubMed]

Baradaran A. Antiphospholipid syndrome-associated nephropathy: A nephropathy needs classification. J Nephropharmacol. 2012;1:7–9.

Nasri H. On the occasion of the world diabetes day 2013; diabetes education and prevention; a nephrology point of view. J Renal Inj Prev. 2013;2:31–2. [PMC free article] [PubMed]

Rafieian-Kopaei M, Nasri H. Serum lipoprotein (a) and atherosclerotic changes in hemodialysis patients. J Renal Inj Prev. 2013;2:47–50. [PMC free article] [PubMed]

Miller ER, III, Appel LJ, Risby TH. Effect of dietary patterns on measures of lipid per-oxidation: Results from a randomized clinical trial. Circulation. 1998;98:2390–5. [PubMed].

For more on this topic, please read the publication contained in the following link:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4115353/

Hoping this will be helpful,

Rafik

Oxidative stress and hypertension: Possibility of hypertension therapy with antioxidants

Azar Baradaran, Hamid Nasri,1 and Mahmoud Rafieian-Kopaei2

Abstract

Hypertension is a major risk factor for myocardial infarction, heart failure, stroke, peripheral arterial disease, and aortic aneurysm, and is a cause of chronic kidney disease. Hypertension is often associated with metabolic abnormalities such as diabetes and dyslipidemia, and the rate of these diseases is increasing nowadays. Recently it has been hypothesized that oxidative stress is a key player in the pathogenesis of hypertension. A reduction in superoxide dismutase and glutathione peroxidase activity has been observed in newly diagnosed and untreated hypertensive subjects, which are inversely correlated with blood pressure. Hydrogen peroxide production is also higher in hypertensive subjects. Furthermore, hypertensive patients have higher lipid hydroperoxide production. Oxidative stress is also markedly increased in hypertensive patients with renovascular disease. If oxidative stress is indeed a cause of hypertension, then, antioxidants should have beneficial effects on hypertension control and reduction of oxidative damage should result in a reduction in blood pressure. Although dietary antioxidants may have beneficial effects on hypertension and cardiovascular risk factors, however, antioxidant supplementation has not been shown consistently to be effective and improvement is not usually seen in blood pressure after treatment with single or combination antioxidant therapy in subjects thought to be at high risk of cardiovascular disease. This matter is the main focus of this paper. A list of medicinal plants that have been reported to be effective in hypertension is also presented.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4115353/

Hi

This is a brief and kindly note the attached articles

Antioxidant capacity during physical exhaustion in people with

cardiovascular diseases

Oxidative stress can cause changes in function of endothelial lining of internal

side of blood vessels. Endothelium is responsible for vessel function, it secretes substances regulating gases and chemical substances transport as well as hormones and molecules determining vessel contraction (e.g. nitric oxide). Aerobic exercise exacerbates oxidative stress, which is connected with an increase of lipid peroxidation, which significantly induces processes of atherosclerosis inside blood vessels [35,43]. On the other hand it is well known that exercise performed on regular basis supports angiogenesis and arteriogenesis, improves tissues blood flow and activates intracellular defence mechanisms against atherosclerosis evolution. Regular physical activity is related to antiapoptotic and fibroblasts antiproliferation activities. It also increases availability of nitric oxide, which improves diastolic reaction on elevated blood pressure [28]. Antioxidant system protects generated

nitric oxide and enables its more efficient use [22]. Existing studies about efficiency of supplementation with ascorbic acid and tocopherol in cardiovascular diseases indicate favourable decrease of lipid peroxidation as well as positive increase of total antioxidant capacity [22,47].

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In subjects with arterial hypertension a higher level of oxidative stress in rest

and during physical activity is reported. In that group the lower activity of

superoxide dismutase and catalase was detected comparing to healthy subjects. Furthermore, the increase of oxidative damage protein products was reported after physical exercise [44].

In subjects with coronary heart disease an increase of superoxide dismutase and glutathione peroxidase activity was detected. The level of oxidized LDL molecules in blood serum also was higher in rest [50]. It may indicate that this group of patients is characterized by increase of chronic oxidative stress despite medical treatment and lack of clinical symptoms. However other experiments showed a decrease of glutathione peroxidase, superoxide dismutase and glutathione with a significant increase of TBARS level in patients with coronary heart disease after exercise test [3]. Similar results were obtained in group of patients with myocardial infarction after cardiogenic shock complications. A decrease of antioxidant enzymes activity in blood serum and in concentration of ascorbic acid, tocopherol and β-carotene were observed [42].

Results published in existing literature indicate an important role of antioxidant

capacity components in pathogenesis of cardiovascular diseases and their

evolution. Results interpretation and comparison with healthy population has to be done with particular attention to differences connected with changes in antioxidant capacity related to the age of examined subjects and also to their pharmacological treatment. It should be additionally considered that physical exercise performed by people with cardiovascular diseases, in secondary prevention as well as in assisting treatment, can also change antioxidant capacity of blood plasma.

Hard to improve on the preceeding answers except to note trivially than another name for superoxide is "Endothelium-derived contracting factor.".  Similarly,  nitric oxide (NO) is tecnuically an ROS.

All the afore mentioned antioxidants have been shown to decrease systemic blood pressure in animal,but their efficacy in humans has not been proven. Mitochondrial oxidative stress seems to play a major role in the pathogenesis of both systemic and pulmonary hypertension. Recent studies have also shown that ROS produced by the mitochondria induce the activation of NADPH oxidases, leading to ROS induced ROS formation and oxidative stress.Targeting antioxidant directly to the mitochondria has been challenging and can produce harmful effects. Studies are ongoing to target mitochondrial oxidative stress.