Enovita, Indena's standardised grape seed extract (GSEe) from Vitis vinifera L. seeds, has previously been found to produce beneficial cardiovascular effects.
The current study aimed to discover the mechanism of action behind this benefit with an in vitro experiment using human umbilical vein endothelial cells (HUVEC).
The results suggested GSEe lead to a significant reduction of the adhesion molecules linked to inflammatory processes in endothelial cells (sICAM, sVCAM, and endothelin-1).
The effect of GSEe on sVCAM appeared less clear but the researchers hypothesised that the elevated soluble Vascular Cell Adhesion Molecule (sVCAM) expression was caused by particle stress.
The researchers then conducted a double-blind, randomised, placebo-controlled parallel group study on 80 adults to discover the impact of the supplement on those with mild hypertension.
Participants (45 male and 35 female, aged 40–70 years) were randomly assigned to receive GSEe or placebo over 16 weeks (two 150 mg tablets every day). Subjects underwent a number of assessments including a range of blood pressure tests, Perceived Stress Questionnaires (PSQ) and quality-of-life questionnaires.
The report finds: "Results from the present randomized, double-blind, placebo-controlled study in mild-hypertensive volunteers indicated that the systolic blood pressure lowering effects were comparable between study groups, with no amelioration seen by 16 weeks’ GSEe supplementation."
This effect was most significantly observed in men.
The study also notes a statistically significant reduction of worries, as well as an improvement of the mental component score, after GSEe supplementation, indicating a potential beneficial effect on stress and mood.
The mechanism of action behind the mood benefit is not certain. The report states: "The positive changes might be attributed to the polyphenol content in GSEe. Polyphenols have been strongly associated with higher cognitive function, better mood, and protective effects against various brain diseases in literature.
"Future perspectives can be planned in order to explore in-depth the potential of GSEe in the stress relaxing field, considering the positive unexpected results observed."
Beneficial properties of grape seed extracts shown by several reports include: antioxidant, anti-inflammatory, neuro-protectant, and free radical scavenging abilities, as anti-proliferative agent or to counteract cellular toxicity by chemotherapeutic agents.
A 4-month administration with GSEe (300 mg/day) in pre- and mildly hypertensive subjects has been demonstrated to be effective in normalising blood pressure in 93% of the supplemented group.
Furthermore, meta-analysis of ten randomised controlled clinical trials with daily grape polyphenol supplementation at different dosages confirmed a significant reduction of systolic blood pressure compared to control group, with no significant reduction in diastolic pressure.
Another meta-analysis data on 16 randomised controlled trials performed by Zhang et al. suggested a positive effect on blood pressure by GSE.
Petrangolini. G., et al
"Grape Seed Extract Positively Modulates Blood Pressure and Perceived Stress: A Randomized, Double-Blind, Placebo-Controlled Study in Healthy Volunteers"