Effects of Onion Peel Extract on Endothelial Function

Study Overview
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Brief Summary
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Acute or chronic intake of polyphenol-rich foods has been reported to improve endothelial function. Quercetin, found abundantly in onion, is a potent antioxidant flavonoid. This study was designed to investigate whether consumption of onion peel extract (OPE) improves endothelial function in healthy overweight and obese subjects.

Detailed Description
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Epidemiological studies have shown a rapid increase in the prevalence of overweight and obesity, not only in adults but also in children and adolescents, thus increasing the risk of early development of cardiovascular disease (CVD). Quercetin, found abundantly in onion, prevents the induction of endothelial dysfunction, superoxide production, and overexpression by angiotensin II in the rat aorta. Furthermore, in our previous study we showed that supplementation with quercetin-rich onion peel extract (OPE) influenced adipokine expression, thus addressing its modulatory effect on obesity-induced inflammation, and improved insulin resistance by alleviating the metabolic dysregulation of free fatty acids, suppressing oxidative stress, upregulating glucose uptake, and downregulating inflammatory gene expression. But there are limited studies on the relationship between quercetin supplementation and endothelial dysfunction in humans.

Official Title
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Effect of Onion Peel Extract on Endothelial Function and Endothelial Progenitor Cells in Overweight and Obese Subjects

Conditions
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Healthy, Overweight, Obese

Intervention / Treatment
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* Drug: Placebo
* Drug: Onion peel extract


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age 20 to 60 years BMI >23 kg/m2 abdominal circumference > 90 cm in males or >85 cm in females Exclusion Criteria: hypertension (>140/90 mmHg), diabetes any cardiovascular disease, kidney disease, thyroid disease cerebrovascular disease liver disease (bilirubin level >2 mg/dl) pregnancy

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Supportive Care
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo<br>Patients treated with placebo for 12 weeks | Drug: Placebo<br>* After randomization, placebo was treated for 12 weeks<br>|
| Experimental: Onion peel extract<br>Patients treated with onion peel extract for 14 days | Drug: Onion peel extract<br>* After randomization, onion peel extract was treated for 12 weeks<br>* Other names: OPE;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The difference of endothelial function | The difference of forearm FMD (flow meidated dilation) achieved following study drug treatment | 12 weeks after study drug treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The difference of EPC (endothelial progenitor cell) counts | After appropriate gating based on low cytoplasmic granularity and low expression of CD45, CD34+VEGFR2+ cells were counted and expressed as the number of cells/106 total events or number of cells/100 µL of blood. | 12 weeks after study drugs treatment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Quercetin, Endothelial function, Onion peel extract, volunteers