Effect of consuming a grape seed supplement with abundant phenolic compounds on the oxidative status of healthy human volunteers.
BACKGROUND
Diverse enzymatic and non-enzymatic antioxidants provide protection against reactive oxygen species in humans and other organisms. The nonenzymatic antioxidants include low molecular mass molecules such as plant-derived phenols.


OBJECTIVE
This study identified the major phenolic compounds of a grape seed extract by HPLC and analyzed the effect of consumption of biscuits enriched with this extract on the urinary oxidative status of healthy subjects by measurement of urine redox potential.


METHODS
The major phenolic compounds were characterized in a red grape seed extract separated by HPLC with detection by a photodiode array (PDA), fluorescence (FL) and quadrupole mass spectrometer (MS). A nutritional study in a healthy volunteers group was done. Each volunteer ate eight traditional biscuits with no red grape seed extract supplementation. The second day each volunteer ate eight traditional biscuits supplemented with 0.6% (wt/wt) of grape seed extract. An overnight urine sample was obtained for each treatment. The redox potential was measured at 25 °C using a potentiometer in each urine sample.


RESULTS
Epicatechin, catechin, procyanidin dimers B1 to B4, and the procyanidin trimer C2 were the major phenolic components in the extract. Epicatechin gallate and procyanidin dimers B1-3-G and B2-3'-G were the major galloylated flavan-3-ols. The forty-six healthy volunteers each shown a reduction of the urine redox potential after the treatment by traditional biscuits supplemented with the grape seed extract.


CONCLUSIONS
This simple dietary intervention significantly reduced (33%) the urine redox potential, reflecting an overall increase in antioxidant status. Incorporation of plant-derived phenols in the diet may increase anti-oxidative status.
Laboratory of Renal Lithiasis Research, University Institute of Health Sciences Research (IUNICS), University of Balearic Islands, 07122, Palma of Mallorca, Spain. fgrases@uib.es.|CIBER Fisiopatología de la Obesidad y Nutrición (CB06/03), Instituto de Salud Carlos III, 07122, Palma of Mallorca, Spain. fgrases@uib.es.
Felix
F
Grases
Laboratory of Renal Lithiasis Research, University Institute of Health Sciences Research (IUNICS), University of Balearic Islands, 07122, Palma of Mallorca, Spain. rafelm.prieto@uib.es.|CIBER Fisiopatología de la Obesidad y Nutrición (CB06/03), Instituto de Salud Carlos III, 07122, Palma of Mallorca, Spain. rafelm.prieto@uib.es.
Rafel M
RM
Prieto
Laboratory of Renal Lithiasis Research, University Institute of Health Sciences Research (IUNICS), University of Balearic Islands, 07122, Palma of Mallorca, Spain. rafelangelfc@yahoo.es.
Rafel A
RA
Fernández-Cabot
Laboratory of Renal Lithiasis Research, University Institute of Health Sciences Research (IUNICS), University of Balearic Islands, 07122, Palma of Mallorca, Spain. antonia.costa@uib.es.|CIBER Fisiopatología de la Obesidad y Nutrición (CB06/03), Instituto de Salud Carlos III, 07122, Palma of Mallorca, Spain. antonia.costa@uib.es.
Antonia
A
Costa-Bauzá
Instituto de Investigación en Ciencias de la Alimentación (CIAL) (CEI, CSIC-UAM), Madrid, Spain. anamaria.sanchez@uam.es.
Ana M
AM
Sánchez
Instituto de Investigación en Ciencias de la Alimentación (CIAL) (CEI, CSIC-UAM), Madrid, Spain. marin.prodanov@uam.es.
Marin
M
Prodanov
D000293:Adolescent; D000328:Adult; D000975:Antioxidants / Q000008:administration & dosage*; D044946:Biflavonoids / Q000008:administration & dosage / Q000652:urine; D002392:Catechin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D019587:Dietary Supplements; D005260:Female; D056604:Grape Seed Extract / Q000008:administration & dosage*; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects*; D010636:Phenols / Q000008:administration & dosage* / Q000652:urine; D044945:Proanthocyanidins / Q000008:administration & dosage / Q000652:urine; D017382:Reactive Oxygen Species / Q000378:metabolism; D012639:Seeds / Q000737:chemistry; D027843:Vitis / Q000737:chemistry*; D055815:Young Adult
D000975:Antioxidants; D044946:Biflavonoids; D056604:Grape Seed Extract; D010636:Phenols; D044945:Proanthocyanidins; D017382:Reactive Oxygen Species; C017674:procyanidin; D002392:Catechin; C062669:epicatechin gallate