The effects of unripe grape extract on systemic blood pressure, nitric oxide production, and response to angiotensin II administration

The Role of Food Supplementation in Microcirculation-A Comprehensive Review

(1) Background: Cardiovascular disease (CVD) is a major public health concern worldwide and a key cause of morbidity and mortality in developed countries. Accumulating evidence shows that several CVD forms are characterized by significant microcirculatory dysfunction, which may both cause and be caused by macrovascular disease, often preceding clinical manifestations by several years. Therefore, interest in exploring food supplements to prevent and restore microcirculation has grown. Given the continuous need to expand the available therapeutic arsenal for CVD, the food supplements market has recently grown and is expected to continue growing. (2) Methods: We provide an authoritative up-to-date comprehensive review of the impact of food supplementation on microcirculation by analyzing the European and American legal food supplements framework and the importance of food safety/food quality in this industry. We review the main literature about food bioactive compounds with a focus on microcirculation and some main food supplements with proven benefits. (3) Results: Despite a lack of scientific evidence, diet and microcirculatory function are clearly connected. The main food supplement examples in the literature with potential beneficial effects on microcirculation are: Ruscus aculeatus L., Centella asiatica L., Ginkgo biloba L., Salvia miltiorrhiza Bunge, Crataegus spp., Ginseng, Mangifera indica L., Aesculus hippocastanum L., Hamamelis virginiana L., and Vitis vinifera L. (4) Conclusions: Further clinical trials are necessary to better explore the effects of these food supplements.

Autonomic Receptors and Nitric-Oxide Involvements in Mediating Vasorelaxation Effect Induced by Syzygium polyanthum Leaves Extract

Context:

Syzygium polyanthum (Wight) Walp leaves are traditionally used by Malays for treating hypertension. Our previous study showed that aqueous extract of S. polyanthum (AESP) and methanolic extract of S. polyanthum (MESP) extracts of S. polyanthum leaves significantly reduced blood pressure of normotensive Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR).

Aims:

This study aimed to investigate their vasorelaxation potential and the possible involvement of autonomic receptors and nitric oxide in mediating their effect.

Settings and Design:

Both extracts will be tested on isolated thoracic aorta rings of WKY and SHR. The involvement of autonomic receptors and nitric oxide will be elucidated using respective blockers.

Materials and Methods:

Isolated thoracic aorta rings from WKY and SHR were mounted onto myograph chambers to measure changes in the aorta tension. Increasing concentrations of AESP and MESP, from 1 μg/ml to 10 mg/ml were added onto the myograph chambers. Blockers such as atropine (1 μM), phentolamine (1 μM), propranolol (1 μM), and Nω-nitro-l-arginine methyl ester (100 μM) were preincubated before addition of extracts to check for involvement of muscarinic, α- and β-adrenergic receptors (AR) as well as nitric oxide, respectively.

Statistical Analysis Used:

Two-way ANOVA, followed by post hoc Bonferroni test was used, where P < 0.05 (two-tailed) was considered statistically significant.

Results:

AESP and MESP caused significant vasorelaxations through nitric oxide pathway. The former was mediated through α-AR while the latter was mediated by β-adrenergic and muscarinic receptors.

Conclusion:

Vasorelaxation effect by AESP and MESP involved nitric oxide pathway which is possibly mediated by the autonomic receptors.

SUMMARY

This is the first study that reveals significant vasorelaxation effect induced by Syzygium polyanthum leaves extract. Vasorelaxation maybe one of the possible mechanisms for its ability to reduce blood pressure. This study also suggested that the vasorelaxation effect by this plant extract may involve nitric oxide pathway mediated by the autonomic receptors.

Abbreviations Used: AESP: Aqueous extract of Syzygium polyanthum leaves. MESP: Methanolic extract of Syzygium polyanthum leaves. SHR: spontaneously hypertensive rat, WKY: Wistar-Kyoto rat.

The effects of unripe grape extract on systemic blood pressure and serum levels of superoxide dismutase, malondialdehyde and nitric oxide in rat

Backgrounds:

The new lifestyle increases the incidence of hypertension. In Iranian folk medicine, it is believed that Verjuice obtained by unripe grape (Vitis vinifera) could control blood pressure. We tested the effects of unripe grape extract (UGE) in blood pressure alteration, serum antioxidant level and aorta endothelial permeability in rats.

Materials and Methods:

Four groups of rats were treated daily by placebo and three different doses of UGE (50, 150 and 300 mg/kg/day). Four weeks later, the animals were anesthetized and catheterized. The direct mean arterial, systolic and diastolic pressures (MAP, SP and DP) were recorded. The endothelial permeability was determined and the serum levels of superoxide dismutase (SOD), malonaldialdehyde (MDA) and nitrite were measured.

Results:

High dose of UGE increased MAP and SP significantly (P < 0.05) when compared with the control group. Decrease of MDA and increase of SOD and nitrite also were detected statistically in animals treated with high dose of UGE (P < 0.05). No difference in aorta endothelial permeability was observed between the groups.

Conclusion:

The effect of UGE on blood pressure was dose dependent. High dose of UGE increased MAP and SP although its antioxidant activity was significantly high. Such observation mechanisms need to be defined.