|
Flavonoid/preparation | Volunteers’ data | Trial data | Main results | Ref. |
|
Quercetin in extract (capsules contained onion skin extract powder (132 mg) with 54 mg quercetin per capsule) | n = 22, male (11), female (11), overweight-to-obese hypertensive patients | randomized, double-blind, controlled, crossover meal study; dosage: long-term supplementation (162 mg/day quercetin) with 6-week treatment periods | (i) no effect of treatment on blood pressure (BP), heart rate, or any biomarker of endothelial function (ii) lack of effect on antioxidant activity and oxidative stress, | [36] |
|
Provex CV (combination of extracts from grape seed and skin (330 mg), green tea (100 mg), resveratrol (60 mg) and a blend of quercetin, ginkgo biloba and bilberry (60 mg)) | n = 20, age: 18 - 65 years, male, female, patient with stage 1 hypertension (metabolic syndrome) | double-blinded, placebo-controlled, randomized, crossover trial; dosage: supplementation with 28-day treatment periods (330 mg Provex CV/day) ClinicalTrials.gov Identifier: NCT01106170 | (i) reduction in diastolic pressure (ii) unchanged systolic pressure (iii) trend to reduction in arterial pressure (iv) potentiation eNOS activation and nitric oxide production | [37] |
|
Pure quercetin-3-glucoside | n = 37, age: 40 - 80 years male, female, healthy (pre)hypertensive participants | double-blind, randomized, placebo-controlled crossover trial; dosage: 160 mg of quercetin-3-glucoside in capsule daily for a period of 4 weeks ClinicalTrials.gov Identifier: NCT01691404 | (i) decrease of plasma sE-selectin, | [38] |
(ii) no effect of treatment on other biomarkers of endothelial dysfunction (sICAM-1, sVCAM-1, and MCP-1), (iii) decrease IL-1b level, (iv) no effect of treatment on other biomarkers of inflammation (CRP, serum amyloid A (SAA), TNF-a, IL-6, IL-8, and sICAM-1), (v) decrease the score for inflammation, (vi) no effect on flow-mediated dilation, insulin resistance, or other CVD risk factors | [39] |
|
quercetin from onion skin extract | n=70 patients with pre-hypertension and stage I hypertension, men, women (25–65 years) | double-blinded, placebo-controlled, randomized cross-over trial dosage: 162 mg/d quercetin per 6 weeks 3x54 mg quercetin per one gelatin capsules | (i) decrease day-time and night-time systolic BP (ii) no changes in vasoactive biomarkers: endothelin-1, soluble endothelial-derived adhesion molecules, asymmetric dimethylarginine, angiotensin-converting enzyme activity, endothelial function, parameters of oxidation, inflammation, lipid and glucose metabolism | [40] |
|
quercetin | n=15 men (9), women (6) (26 ± 5 years) | double-blind, placebo-controlled, randomized crossover study dosage: 200 and 400 mg of quercetin per 3 weeks | (i) 400 mg increased the plasma levels of glutathione (ii) no changes in systolic and diastolic blood pressure after 2 and 5h post ingestion of 200 and 400 mg quercetin | [41] |
|
quercetin | n = 12 of stage 1 hypertensive men (41 ± 12 years) n = 5 of normotensive men (24 ± 3 years) | double-blind, placebo-controlled, crossover trial dosage: 1095 mg of quercetin in tablet per 7 days | hypertensive men: (i) decrease in systolic, diastolic, and mean BP at 10 hours post quercetin ingestion (ii) no effect on plasma ACE activity, NO metabolites, ET-1, and the ratio of ET-1:NO metabolites, relative flow-mediated dilation (FMD) normotensive men: (i) no effect of supplementation on BP, heart rate, ACE activity | [42] |
|
quercetin | n = 587 participants (299 in quercetin group; 288 in control group) | 7 placebo-controlled randomized controlled trials (between 1998 and 2014). Ranges of doses from 100 to 1000 mg/ day of quercetin per 4 and 10 weeks | conclusion of meta-analysis: (i) statistically significant effect of quercetin supplementation in the reduction of blood pressure (systolic and diastolic BP), possibly limited to, or greater with dosages of >500 mg/day, (ii) oral quercetin administration was safe and well tolerated, | [43] |
|