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Dietary Bioactive Components (Poster Session)

(P04-013-24) Effect of Proanthocyanidin Supplementation on Markers of Oxidative Stress in Healthy Subjects: A Pilot Randomized, Placebo-Controlled, Crossover Intervention

Sunday, June 30, 2024
11:45 AM – 12:45 PM CT
Location: Poster Board 90
Disclosure(s):
Cristian Del Bo', PhD: No relevant financial relationship(s) with ineligible companies to disclose.
Mirko Marino, PhD: No relevant financial relationship(s) with ineligible companies to disclose.
Marco Rendine, MD Biological Sciences - Nutrition and Functional Foods: No relevant financial relationship(s) with ineligible companies to disclose.
Patrizia Riso, PhD: No relevant financial relationship(s) with ineligible companies to disclose.


Objectives: Proanthocyanidins (PACs) are a class of polyphenols poorly absorbed and extensively metabolized by gut microbiota whose metabolic products have shown potential biological effects in particular against oxidative stress. However, in humans results are still controversial. The aim of the study was to evaluate the ability of PACs to affect oxidative stress markers in a group of volunteers.

Methods: Twelve healthy participants (age: 25-35 years; BMI: ≥ 18.5 and < 24.9 Kg/m2) were randomly allocated to consume two capsules per day of oligomeric proanthocyanidins (300 mg) from a grape seed extract or placebo (dibasic calcium phosphate) for 7 days. Each intervention was separated by a 1-week washout period. At time zero and after 7-day of supplementation, blood and urine samples were collected to analyze PAC metabolites by LC-MS, and oxidative stress markers such as protein carbonyl (PC), oxidized low-density lipoprotein (Ox-LDL), and 8-hydroxy-2-deoxyguanosine (8-OHdG), by ELISA kits. Furthermore, endogenous and oxidatively-induced DNA damage was assessed at the level of blood mononuclear cells by the Comet assay. Compliance was assessed by administering a 7-day food diary.

Results: Participants showed a full compliance to the intervention and no one declared adverse effects from PAC consumption. The intervention revealed that PACs were metabolized and 5-(3',4'-dihydroxyphenyl)-γ-valerolactone (γ-V) was identified as the main metabolic product in plasma (~ 35 nmol/L) and urine (~ 40 µmoles/24 hours, as sulfate and glucuronide phase II metabolites). A trend towards reduction was observed for the levels of oxidatively-induced DNA damage and urinary 8-OHdG in subjects consuming PACs, but not with respect to placebo. No effect was observed for serum Ox-LDL, PC, 8-OHdG, and endogenous DNA damage.

Conclusions: The results obtained do not seem to support the role of PACs in the modulation of the markers considered. Further studies, on a large sample size, longer term or in subjects with risk factors, are necessary to clarify the potential impact of PACs in the management of oxidative stress.

Funding Sources: The study was supported by intramural funding. Distillerie Bonollo Umberto SpA provided the oligomeric proanthocyanidin extract (Ecovitis®) and placebo.