Effects of grape seed extract consumption on platelet function in postmenopausal women

The Anti-inflammatory Potential of Selected Plant-derived Compounds in Respiratory Diseases

Inflammation plays a major role in chronic airway diseases like asthma, COPD, and cystic fibrosis. Inflammation plays a crucial role in the worsening of the lung function resulting in worsening symptoms. The inflammatory process is very complexed, therefore the strategies for developing an effective treatment for inflammatory airway diseases would benefit from the use of natural substances. Plant products have demonstrated anti-inflammatory properties on various lung disease models and numerous natural plant agents have successfully been used to treat inflammation. Naturally occurring substances may exert some anti-inflammatory effects by modulating some of the inflammatory pathways. These agents have been used in different cultures for thousands of years and have proven to be relatively safe. Parthenolide, apocynin, proanthocyanidins, and boswellic acid present different mechanisms of actions - among others, through NF-kB or NADPH oxidase inhibition, therefore showing a wide range of applications in various inflammatory diseases. Moreover, some of them have also antioxidant properties. This review provides an overview of the anti-inflammatory effects of some of the natural agents and illustrates their great potential as sources of drugs to cover an extensive range of pharmacological effects.

The effect of polyphenol-rich chardonnay seed supplements on peripheral endothelial function

OBJECTIVE

Peripheral endothelial dysfunction (PED) is associated with major adverse cardiovascular events. Similar to cardio-protective Mediterranean diet, Chardonnay seeds are rich in polyphenols, fibers, and grape seed oil. In this randomized double-blinded trial, we investigated safety and incremental benefit of Chardonnay seed polyphenols-rich (PR), compared to polyphenols-free (PF), supplements on PED.

METHODS

89 patients with PED [reactive hyperemia-peripheral arterial tonometry (RH-PAT) index ≤ 2) were randomized 1:1 to 4.8 g (6 capsules)/day PR or PF for 4 months. PR and PF capsules had equal amounts of seed oil (~ 7% capsule weight), fibers, and carbohydrates, but only PR capsules contained polyphenols (~ 11% capsule weight). Baseline and follow-up RH-PAT indices (primary endpoint) and endothelial progenitor cells (EPC) levels were measured. Patients were asked to maintain their regular diet and exercise habits during study period.

RESULTS

Baseline RH-PAT indices, demographics, lab values, and EPC levels were similar between groups. No significant adverse reactions to PR or PF were reported. Follow-up RH-PAT indices significantly increased (p < 0.05 vs. baseline) in both groups to similar extent (31 ± 39% PR vs. 49 ± 53% PF, p = 0.09). Circulating CD34 + EPCs equally increased (median + 55% vs. + 54%, p = 0.94) in PR and PF groups, respectively.

CONCLUSION

PR and PF Chardonnay seed supplements were safe and improved peripheral endothelial function to similar extent in PED patients. However, there were no incremental benefits of PR over PF on RH-PAT indices or CD34 + EPC levels. Chardonnay seed supplements role in primary prevention of atherosclerosis, as add-on to healthy lifestyle and guidelines directed medical therapy, should be further explored. CLINICALTRIALS.

GOV IDENTIFIER (NCT NUMBER)

NCT02093455.

Therapeutic potential of natural compounds in inflammation and chronic venous insufficiency

The term varicose vein refers to the twisted and swollen vein visible under the skin surface which occurs most commonly in the leg. Epidemiological studies report a varying percentage of incidences from 2 to 56% in men and <1-60% in women. Venous insufficiency is most often caused by the damage to the valves and walls of the veins. The mechanism of varicose vein formation is complex. It is, however, based on hypotensive blood vessels, hypoxia, and other mechanisms associated with inflammation. This work describes mechanisms related to the formation and development of the varicose vein. It discusses risk factors, pathogenesis of chronic venous disease, markers of the epithelial and leukocyte activation, state of hypoxia and inflammation, reactive oxygen species (ROS) generation, and oxidative stress. Additionally, this paper describes substances of plant origin used in the treatment of venous insufficiency. It also considers the structure of the molecules, their properties, and their mechanisms of action, the structure-activity relationship and chemical properties of flavonoids and other substances. The flavonoids include quercetin derivatives, micronized purified flavonoid fraction (Daflon), natural pine bark extract (Pycnogenol), and others such as triterpene saponine, extracts from Ruscus aculeatus and Centella asiatica, Ginkgo biloba extract, coumarin dereivatives that are used in chronic venous insufficiency. Flavonoids are natural substances found in plants, including fruits, vegetables, flowers, and others. They are important to the circulatory system and critical to blood vessels and the blood flow. Additionally, they have antioxidant, antiinflammatory properties.

Male Infertility: The Effect of Natural Antioxidants and Phytocompounds on Seminal Oxidative Stress

Defective sperm function has been identified as the most common cause of infertility. The objective of this study was to review recent findings on the effects of various antioxidants on male fertility. High amounts of poly unsaturated fatty acid are found in the mammalian spermatozoa membranes, thereby making them susceptible to lipid peroxidation. Although, free radicals and reactive oxygen species (ROS) play major roles in reproduction, they are strongly associated with oxidative stress. Furthermore, factors such as obesity, inflammation, pollutants and cigarette smoking are negatively correlated with spermatogenesis. Endogenous antioxidants system exists to mediate these damages. In a normal physiological state, the seminal plasma contains antioxidant enzyme mechanism that is capable of quenching these ROS as well as protecting the spermatozoa against any likely damage. However, high level of ROS triggered by inflammatory cells and oxidation of fatty acid in obese subjects may down play antioxidant mechanism resulting in oxidative stress. Evaluation of such oxidative stress is the first step in the treatment of male infertility through administration of suitable antioxidant. Notably, antioxidant such as vitamin E and C, carotenoids and carnitine have been found beneficial in restoring a balance between ROS generation and scavenging activities. There are emerging evidences that herbal products can also boost male reproductive functions. Nonetheless, a good lifestyle, regular exercise, avoidance of stress and observing safety rules at work are habits that can reverse male infertility.

Dietary manipulation of platelet function

Activated platelets contribute to plaque formation within blood vessels in the early and late stages of atherogenesis, and therefore they have been proposed as risk factor for cardiovascular disease. Anti-platelet drugs, such as aspirin, are now the most prescribed pharmacological treatment in Europe. Certain dietary bioactives also beneficially affect platelet function, and with less side effects, albeit that effects are generally more subtle. Therefore, consumption of dietary bioactives could play a role in the prevention of atherothrombotic vascular disease. Here we review the efficacy of dietary treatment strategies, especially those involving certain dietary fatty acids and polyphenols, to modulate platelet function in healthy subjects or in patients with cardiovascular disease. Variation in study populations, small study sizes and lack of comparability between methods to assess platelet function currently limit robust evidence on the efficacy of dietary bioactives in healthy subjects or specific patient groups. Also, limited knowledge of the metabolism of dietary bioactives, and therefore of the bioavailability of bioactive ingredients, restricts our ability to identify the most effective dietary regimes to improve platelet function. Implementation of uniform point-of-care tests to assess platelet function, and enhanced knowledge of the efficacy by which specific dietary compounds and their metabolites affect platelet function, may enable the identification of functional anti-platelet ingredients that are eligible for a health claim, or combined treatment strategies, including both pharmacological anti-platelet treatment as well as dietary intervention, to tackle atherothrombotic vascular disease.

Lack of effect of bioactive-rich extracts of pomegranate, persimmon, nettle, dill, kale and Sideritis and isolated bioactives on platelet function

BACKGROUND

The health benefits of fruit and vegetable-rich diets may be partly due to modulation of platelet activity by bioactive phytochemicals. The aim of this study was to investigate the effects of bioactive-rich plant extracts and isolated bioactive metabolites on platelet function. Blood samples (n =15 subjects) were treated with extracts of bioactive-rich plants consumed as traditional foods in the Black Sea region, or with human metabolites of the bioactives quercetin and sulforaphane. Platelet function was assessed using the PFA-100.

RESULTS

None of the extracts containing various flavonoids, glucosinolates and other bioactives, or isolated bioactive metabolites of quercetin or sulforaphane, caused significant changes in PFA-100 closure time (CT). In contrast, the positive controls (aspirin and Abciximab) consistently caused significant increases in CT for the platelet agonists epinephrine and ADP, respectively.

CONCLUSION

These data do not support the notion that these plant bioactives can improve human platelet function.

Effect of polyphenol-rich grape seed extract on ambulatory blood pressure in subjects with pre- and stage I hypertension

Dietary polyphenols, such as those from grape products, may exert beneficial effects on cardiovascular health, including anti-hypertensive effects. We investigated the effect of a specific grape seed extract (GSE) rich in low-molecular-weight polyphenolic compounds on ambulatory blood pressure (ABP) in untreated subjects with pre- and stage I hypertension. In addition, potential mechanisms that could underlie the hypothesised effect of GSE on blood pressure (BP), and platelet aggregation, were explored. The study was designed as a double-blind, placebo-controlled, randomised, parallel-group intervention study including seventy healthy subjects with systolic BP between 120 and 159 mmHg. A 1-week run-in period was followed by an 8-week intervention period, during which subjects consumed capsules containing either 300 mg/d of GSE or a placebo (microcrystalline cellulose). Before and after the intervention, daytime ABP readings, 24 h urine samples and fasting and non-fasting blood samples were taken. The mean baseline systolic BP was 135·8 (se 1·3) mmHg and diastolic BP was 81·5 (se 0·9) mmHg. BP values were modestly, but not significantly, affected by the polyphenol-rich GSE treatment v. placebo with an effect of − 3·0 mmHg for systolic BP (95 % CI − 6·5, 0·5) and − 1·4 mmHg for diastolic BP (95 % CI − 3·5, 0·6). Vasoactive markers including endothelin-1, NO metabolites and asymmetric dimethylarginine, plasma renin activity and platelet aggregation were not affected by the GSE intervention. Our findings show that consumption of polyphenol-rich GSE does not significantly lower ABP in untreated subjects with pre- and stage I hypertension.

Grape Seed Extracts Inhibit Platelet Aggregation by Inhibiting Protein Tyrosine Phosphatase

Platelets play an important role in various thrombotic diseases, including myocardial infarction. Because red wine consumption is inversely associated with death due to ischemic heart diseases, the effects of grape components on platelet function have been extensively investigated. Grape seed extracts (GSEs) reportedly inhibit platelet aggregation; however, the underlying mechanism has not been elucidated. We discovered that GSEs inhibit platelet aggregation induced by collagen and thrombin-receptor agonist peptide and increase basal levels of tyrosine phosphorylation, which was also observed in the presence of a protein tyrosine phosphatase (PTP) inhibitor. An in vitro phosphatase assay indicated that GSE dose dependently inhibited PTP-1B and Src homology 2 domain-containing phosphatase-1 activity, which positively regulates platelet aggregation. We propose that GSEs inhibit platelet aggregation by inhibiting tyrosine phosphatase activity. Moreover, we showed that GSE ingestion inhibited platelet aggregation in mice without enhancing tail bleeding, implying that GSE supplementation might be beneficial to prevention of thrombotic diseases.

The potential of flavanol and procyanidin intake to influence age-related vascular disease

Advancing age is an independent major risk factor for cardiovascular disease (CVD). Age-associated impairments in the control of inflammation, excessive oxidative stress, and reduced cellular repair can all contribute to the development and progression of CVD. Current recommendations for both the primary and secondary prevention of CVD promote lifestyle modifications that include the adoption of healthy dietary patterns, such as the consumption of diets rich in plant foods, as these have been associated with a lower lifetime risk for the development of CVD. The potential for a diet rich in plant foods to be cardiovascular protective is also supported by prospective studies that suggest the intake of foods providing high amounts of certain phytochemicals, in particular flavanols and procyanidins, reduce the risk for CVD. These observations are further supported by a number of dietary intervention trials that show improvements in vascular function and reduced platelet reactivity following the consumption of high flavanol foods. In the current article we review a selection of these studies, and comment on some of the potential mechanisms that have been postulated to underlie the health effects of flavanol and procyanidin-rich foods.

The effect of grape seed extract on cardiovascular risk markers: a meta-analysis of randomized controlled trials

Recent animal studies have suggested that grape seed extract has beneficial effects on the cardiovascular system. Randomized trials in human beings have yielded conflicting results. The objective of this systematic review was to assess the effect of grape seed extract on changes in blood pressure, heart rate, lipid levels, and C-reactive protein (CRP) levels. We searched MEDLINE (January 1, 1950, through October 31, 2010), Agricola (January 1, 1970, through October 31, 2010), Scopus (January 1, 1996, through October 31, 2010), and the Cochrane Central Register of Controlled Trials (through October 31, 2010) for randomized controlled trials in human beings of grape seed extract reporting efficacy data on at least one of the following end points: systolic or diastolic blood pressure, heart rate, total cholesterol, low-density or high-density lipoprotein cholesterol, triglycerides, or CRP. A manual search of references from primary and review articles was performed to identify additional relevant trials. For all endpoints except CRP, the mean change in each parameter from baseline was treated as a continuous variable and the effect size was calculated as the weighted mean difference between the means in the grape seed extract and control groups. Data on CRP were pooled as a standardized mean difference. Nine randomized, controlled trials (N=390) met the inclusion criteria, and a meta-analysis was conducted. Upon meta-analysis, grape seed extract significantly lowered systolic blood pressure (weighted mean difference -1.54 mm Hg (95% confidence interval -2.85 to -0.22, P=0.02]), and heart rate (weighted mean difference -1.42 bpm (95% confidence interval -2.50 to -0.34, P=0.01]). No significant effect on diastolic blood pressure, lipid levels, or CRP was found. No statistical heterogeneity was observed for any analysis (I(2)<39% for all). Egger's weighted regression statistic suggested low likelihood of publication bias in all analysis (P>0.05 for all), except for the effect on diastolic blood pressure (P=0.046). Based on the currently available literature, grape seed extract appears to significantly lower systolic blood pressure and heart rate, with no effect on lipid or CRP levels. Larger randomized, double-blinded trials evaluating different dosages of grape seed extract and for longer follow-up durations are needed.

Modulation of endogenous antioxidant system by wine polyphenols in human disease

Numerous studies indicate that moderate red wine consumption is associated with a protective effect against all-cause mortality. Since oxidative stress constitutes a unifying mechanism of injury of many types of disease processes, it should be expected that polyphenolic antioxidants account for this beneficial effect. Nevertheless, beyond the well-known antioxidant properties of these compounds, they may exert several other protective mechanisms. Indeed, the overall protective effect of polyphenols is due to their large array of biological actions, such as free radical-scavenging, metal chelation, enzyme modulation, cell signalling pathways modulation and gene expression effects, among others. Wine possesses a variety of polyphenols, being resveratrol its most outstanding representative, due to its pleiotropic biological properties. The presence of ethanol in wine aids to polyphenol absorption, thereby contributing to their bioavailability. Before absorption, polyphenols must be hydrolyzed by intestinal enzymes or by colonic microflora. Then, they undergo intestinal and liver metabolism. There have been no reported polyphenol adverse effects derived from intakes currently associated with the normal diet. However, supplements for health-protection should be cautiously used as no level definition has been given to make sure the dose is safe. The role of oxidative stress and the beneficial effects of wine polyphenols against cardiovascular, cancer, diabetes, microbial, inflammatory, neurodegenerative and kidney diseases and ageing are reviewed. Future large scale randomized clinical trials should be conducted to fully establish the therapeutic use of each individual wine polyphenol against human disease.

Biomedical effects of grape products

Accumulating evidence suggests that consumption of grapes and grape products can positively influence risk factors associated with cardiovascular health, cancer, neurodegenerative disease, and age-related cognitive decline. These effects are often attributed to the antioxidant activity and function of flavonoid compounds found in grapes as well as other actions such as increasing nitric oxide production. The well-established health effects of grapes on cardiovascular disease risk, mainly on endothelial function, LDL oxidation, progression of atherosclerosis, and reduction in oxidative stress, have been clearly identified. Emerging research has also demonstrated that grapes have beneficial effects on other chronic-degenerative diseases such as cancer, Alzheimer's disease, age-related cognitive decline, and diabetes. Further beneficial effects of grapes on oral health, immune function, and antiviral activity have also been reported. This review examines the published evidence on the human health benefits associated with grapes and grape products, with animal and cell studies included for areas in which human research is either limited or unavailable.