It is well established that endothelial dysfunction is an early predictor of cardiovascular events in at-risk patients. Finding safe and effective product able to improve endothelial function is of public health interest.

Many clinical studies have shown that monomer of flavanols from cocoa significantly improved endothelial function, in particular endothelium-dependent flow-mediated dilation (ED-FMD) after a single dose. Grape is also a main source of flavanol monomers, that's why many human studies have shown significant effects of grape-derived products on endothelial function within 2 hours following a single dose intake.

The objective of this study is to assess the effect of 2 doses of a proprietary and standardised botanical blend rich in polyphenols (SBRP), on ED-FMD in fasting conditions, in comparison to a placebo, in healthy adults. This blend is made of two botanical extracts: a grape extract and a blueberry extract. In order to provide supportive evidence on the mechanisms and biological plausibility to the clinical effects of the product, appropriate biological parameters and circulating metabolites will be assayed.

Inclusion Criteria:

• Presenting at least two of the following risks of suboptimal endothelial function (but not under prescribed drug for this reason):
• Overweight, defined by: 25 ≤ BMI < 30 kg/m2;
• Central obesity defined according to IDE criteria (2009): for European subjects, waist circumference ≥ 94 cm (with a tolerance of -10%);
• High Normal Blood pressure defined according to ESC/ESH guidelines (2013): Systolic Blood Pressure ≥ 130 and ≤ 139 mmHg or Diastolic Blood Pressure ≥ 85 and ≤ 89 mmHg;
• Considered healthy based on their self-declaration and physical examination;
• Subjects capable of and willing to comply with the protocol and to give their written informed consent.
• Subjects affiliated with a social security scheme.

Non-inclusion Criteria:

• Metabolic abnormality or major cardiovascular risk factor, such as (but not limited to):
• clinically significant arrhythmia,
• diabetes mellitus (type I or II),
• chronic kidney disease.
• Consumption of food supplement(s) currently or within the past 4 weeks before entry into the study, such as but not limited to: botanicals, vitamins, minerals, amino acids;
• Smoking > 5 cigarettes/ day and > 5 pack-years for at least 2 years;
• Use of any type of medication currently or within 2 months before entry into the study (more especially antihypertensive drug);
• Use of any narcotic drug (including cannabis) within 2 months before entry into the study detected by the self-declaration of the participant and/ or by the urine THC test ;
• Endurance sport activities > 5 h/ week;
• Self-reported alcohol intake >10 units/ week (1 unit = 1 standard glass)
• Weight change > 5% of total body weight within the 3 months before V1;
• Currently under prescribed diet regimen, whatever the reason;
• Any intolerance or allergy documented or suspected to one of the components of the study products or to the Glyceryl trinitrate (GTN);
• Any contraindication to the GTN drug:
• severe hypotension,
• obstructive cardiomyopathy,
• myocardial infarction,
• intracranial hypertension,
• sildenafil intake (occasionally or regularly). .
• Subject presenting a psychological or linguistic inability to sign the informed consent;
• Subject under legal protection (guardianship, wardship) or deprived from his rights following administrative or judicial decision;
• Subject participating in another biomedical study or participation in another study within the 3 months before entry into this study;
• Any regulatory reason according to national applicable regulation.

Exclusion criteria :

Volunteers whose fasting blood sample at V0 will reveal a pathological level of glycaemia (> 1,26 g/L) and/ or a dyslipidemia (example : triacylglycerol > 1,75 g/L) will be excluded.