Review Article

Pharmacological Effect of Quercetin in Hypertension and Its Potential Application in Pregnancy-Induced Hypertension: Review of In Vitro, In Vivo, and Clinical Studies

Table 2

Recent randomized controlled trials of quercetin-based formulations and hypertension.

Flavonoid/preparationVolunteers’ 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-glucosiden = 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 extractn=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]

quercetinn=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]

quercetinn = 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]

quercetinn = 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]