Uncovering the Vasorelaxant Effect Induced by Vale do São Francisco Red Wine: A Role for Nitric Oxide:

Alcohol - The myth of cardiovascular protection

BACKGROUND & AIMS

To investigate potential biases that exist in available epidemiological evidence resulting in negative associations or underestimation of cardiovascular (CV) risk associated with alcohol consumption.

METHODS

UK Biobank involved baseline data collection from 22 assessment centres across the United Kingdom. The cohort consisted of 333 259 alcohol consumers and 21 710 never drinkers. Participants were followed up for a median 6.9 years capturing incident fatal and non-fatal CV events, ischemic heart disease and cerebrovascular disease. Alcohol intake was reported as grams/week.

RESULTS

Using never drinkers as reference, alcohol from all drink types combined (hazard ratios ranging between 0.61 and 0.74), beer/cider (0.70-0.80) and spirits combined, and all wines combined (0.66-0.77) associated with a reduced risk for all outcome measures (all CV events, ischaemic heart disease, cerebrovascular disease). In continuous analysis, alcohol captured from all drink types combined (hazard ratio, 1.08, 95% confidence interval, 1.01-1.14), and beer/cider and spirits combined (1.24, 1.17-1.31) associated with an increased risk for overall CV events, however hazard ratios were stronger for beer/cider and spirits (P < 0.0001). Wine associated with a reduced risk for overall CV events (0.92, 0.86-0.98) and ischemic heart disease (0.75, 0.67-0.84). This negative relationship with overall CV events was lost after excluding ischemic heart disease events (1.00, 0.93-1.08), while the positive association of alcohol captured from beer/cider and spirits remained significant (1.30, 1.22-1.40). This positive association with overall CV events was present even when consuming less than 14 units per week.

CONCLUSIONS

Avoiding potential biases prevents underestimation of cardiovascular risk and indicates that consuming up to 14 units per week also associated with increased CV risk in the general population.

A systematic review with meta-analysis on the antihypertensive efficacy of Nigerian medicinal plants

ETHNOPHARMACOLOGICAL RELEVANCE

Despite the promising effects of herbal preparations in lowering blood pressure (BP), hypertension remains a major clinical challenge in Nigeria. The BP-lowering effects of medicinal plants are due to the presence of bioactive compounds.

AIM OF THE STUDY

This meta-analysis presents a precise estimate of the therapeutic benefits of medicinal plants utilized in Nigeria for the management of hypertension in animals and humans.

METHODS

A systematic literature search was performed through Cochrane, PubMed, Science Direct and Scopus databases from inception until February 28, 2021 using search terms related to randomized controlled trials of Nigerian medicinal plants for hypertension. Additional studies were identified through manual search. BP was the main outcome that was measured after the intervention. Meta-analysis was performed using the Review Manager and Meta-Essential.

RESULTS

Nineteen trials comprising of 16 preclinical and 3 clinical studies were enrolled for the meta-analysis. A total number of 16 plants was identified of which H. sabdariffa was the highest reported plant. The plant extracts significantly lowered the systolic blood pressure (SBP) and diastolic blood pressure (DBP) of the hypertensive subjects compared to control. Weighted mean difference (WMD) for SBP (-43.60 mmHg, 95% CI: -63.18, -24.01; p<0.0001) and DBP (-29.50 mmHg, 95 CI: -43.66, -15.34; p<0.0001) was observed for the preclinical studies. For clinical trials, the WMD was -13.98 mmHg, 95 CI: -19.08, -8.88; p<0.00001 for SBP and -10.00 mmHg, 95 CI: -12.22, -7.78; p<0.00001 for DBP. High heterogeneity was observed for the outcome measures of preclinical studies, but not for the clinical studies. The observed substantial heterogeneity in preclinical studies may be linked to methodological shortcomings as evidenced by the results of the risk of bias assessment. There was no evidence of publication bias in animal trials for BP using the funnel plot and Egger's regression test (SBP, p=0.239 and DBP, p=0.112).

CONCLUSIONS

This study provides evidence of medicinal preparations for the treatment of hypertension. A well-conducted trial with methodological rigour and a longer duration of follow-up is required for their effective clinical utilization.

Antioxidant and vasorelaxant activities induced by northeastern Brazilian fermented grape skins

Background

In northeastern Brazil, grape pomace has become a potential alternative byproduct because of the recover phenolic compounds from the vinification process. Comparative analyses were performed between lyophilized extract of grape skins from pomace, described as fermented (FGS), and fresh, unfermented (UGS) grape skins to show the relevant brand’s composition upon the first maceration in winemaking.

Methods

The use of in vitro testing such as Folin-Ciocalteu’s, DPPH free radical scavenger and HPLC methods were performed to evidence antioxidant effect and phenolic compounds. Additionally, vascular reactivity studies were performed in third-order branches of rat superior mesenteric arteries, which were obtained and placed in organ baths containing Krebs-Henseleit solution, maintained at 37 °C, gassed with a mixture of 95% O₂ and 5% CO₂, and maintained at pH 7.4. The in situ formation of reactive oxygen species (ROS) was evaluated in small mesenteric rings using oxidative fluorescent dihydroethidium dye.

Results

We found higher phenolic content and antioxidant activity in FGS when compared to UGS. HPLC analyses identified a significant number of phenolic compounds with antioxidant potential in both samples. The vasorelaxant effect induced by FGS was more potent than that induced by UGS, and the activity was attenuated after removal of vascular endothelium or by blockade of endothelium-derived relaxing factors, such as NO and EDHF.

Conclusions

The FGS extract may be a great source of natural polyphenol products with potent antioxidant effects and endothelium-dependent vasodilatory actions involving NO and EDHF pathways.

Antioxidant and Antihypertensive Effects of a Chemically Defined Fraction of Syrah Red Wine on Spontaneously Hypertensive Rats

A particularly phenolic-rich fraction extracted from red wine from the São Francisco valley (Northeastern Brazil) was chemically characterized and its hypotensive and antioxidant effects on spontaneously hypertensive rats were studied both in vitro and in vivo. The liquid-liquid pH dependent fractionation scheme afforded a fraction with high content of bioactive phenolics such as flavonols, flavonol glycosides, phenolic acids and anthocyanins, whose identities were confirmed by liquid chromatography coupled to mass spectrometry analysis. Pretreatment of spontaneously hypertensive rats with this wine fraction at doses of 50 and 100 mg/kg by gavage for 15 days was able to decrease mean arterial pressure and heart rate as well as decrease serum lipid peroxidation. The fraction at concentrations of 0.01–1000 µg/mL induced concentration-dependent relaxation of isolated rat superior mesenteric artery rings pre-contracted with phenylephrine and this effect was not attenuated by endothelium removal. Our results demonstrate it is possible for phenolic constituents of red wine that are orally bioavailable to exert in vivo hypotensive and antioxidant effects on intact endothelial function.

Alcoholic Beverage Consumption and Chronic Diseases

Epidemiological and experimental studies have consistently linked alcoholic beverage consumption with the development of several chronic disorders, such as cancer, cardiovascular diseases, diabetes mellitus and obesity. The impact of drinking is usually dose-dependent, and light to moderate drinking tends to lower risks of certain diseases, while heavy drinking tends to increase the risks. Besides, other factors such as drinking frequency, genetic susceptibility, smoking, diet, and hormone status can modify the association. The amount of ethanol in alcoholic beverages is the determining factor in most cases, and beverage types could also make an influence. This review summarizes recent studies on alcoholic beverage consumption and several chronic diseases, trying to assess the effects of different drinking patterns, beverage types, interaction with other risk factors, and provide mechanistic explanations.