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The antioxidant effects of a polyphenol-rich grape pomace extract in vitro do not correspond in vivo using exercise as an oxidant stimulus.

Veskoukis AS, Kyparos A, Nikolaidis MG, Stagos D, Aligiannis N, Halabalaki M, Chronis K, Goutzourelas N, Skaltsounis L, Kouretas D - Oxid Med Cell Longev (2012)

Bottom Line: Numerous studies have examined the effects of plant extract administration on redox status at rest in animals and humans but their results are controversial.Our findings indicate that the tested extract exhibits potent in vitro antioxidant properties because it scavenges the DPPH(•) and ABTS(•+) radicals and inhibits DNA damage induced by peroxyl and hydroxyl radicals.Our findings suggest that the grape pomace extract does not behave with the same way in vitro and in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Biotechnology, University of Thessaly, 41221 Larissa, Greece.

ABSTRACT
Fruits, such as grapes, are essential food of the Mediterranean diet. Grape extracts have potent antioxidant and chemopreventive properties in vitro. Numerous studies have examined the effects of plant extract administration on redox status at rest in animals and humans but their results are controversial. However, there are no studies comparing the in vitro and in vivo effects of plant extracts on oxidative stress using exercise as an oxidant stimulus. Thus, the aim of this study was to investigate whether a polyphenol-rich grape pomace extract of the Vitis vinifera species possesses in vitro antioxidant properties and to examine whether these properties apply in an in vivo model at rest and during exercise. Our findings indicate that the tested extract exhibits potent in vitro antioxidant properties because it scavenges the DPPH(•) and ABTS(•+) radicals and inhibits DNA damage induced by peroxyl and hydroxyl radicals. Administration of the extract in rats generally induced oxidative stress at rest and after exercise whereas exercise performance was not affected. Our findings suggest that the grape pomace extract does not behave with the same way in vitro and in vivo.

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Effects of the grape pomace extract on oxidative stress markers in plasma at rest and postexercise. *Significantly different from the rest value within either the saline or the extract group (P < 0.05). #Significantly different between the saline- and the extract-treated groups at the same time point (P < 0.05).
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fig3: Effects of the grape pomace extract on oxidative stress markers in plasma at rest and postexercise. *Significantly different from the rest value within either the saline or the extract group (P < 0.05). #Significantly different between the saline- and the extract-treated groups at the same time point (P < 0.05).

Mentions: In xanthine oxidase (Figure 3(a)), significant main effects of treatment and time were found. In post hoc within-group comparisons, xanthine oxidase activity significantly increased after exercise in the saline-treated group only. In post hoc between-group comparisons, xanthine oxidase activity was significantly lower in the extract group compared to the saline group, both at rest and at postexercise. In TAC (Figure 3(b)), significant main effects of treatment and time were found. In the within-group comparisons, TAC increased after exercise in both saline- and extract-treated groups. In the between-group comparisons, TAC was higher in the extract group compared to the saline group at postexercise only. In protein carbonyls (Figure 3(c)) significant main effects of treatment, time, as well as interaction of treatment × time were found. In the within-group comparisons, protein carbonyl concentration increased after exercise in both saline and extract-treated groups. In the between-group comparisons, protein carbonyl concentration was higher in the extract group compared to saline group at rest only. In TBARS (Figure 3(d)) significant main effects of treatment and time were found. In the within-group comparisons, TBARS concentration increased after exercise in the saline-treated group only. In the between-group comparisons, TBARS concentration was higher in the extract-treated group compared to the saline-treated group at rest only.


The antioxidant effects of a polyphenol-rich grape pomace extract in vitro do not correspond in vivo using exercise as an oxidant stimulus.

Veskoukis AS, Kyparos A, Nikolaidis MG, Stagos D, Aligiannis N, Halabalaki M, Chronis K, Goutzourelas N, Skaltsounis L, Kouretas D - Oxid Med Cell Longev (2012)

Effects of the grape pomace extract on oxidative stress markers in plasma at rest and postexercise. *Significantly different from the rest value within either the saline or the extract group (P < 0.05). #Significantly different between the saline- and the extract-treated groups at the same time point (P < 0.05).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3368594&req=5

fig3: Effects of the grape pomace extract on oxidative stress markers in plasma at rest and postexercise. *Significantly different from the rest value within either the saline or the extract group (P < 0.05). #Significantly different between the saline- and the extract-treated groups at the same time point (P < 0.05).
Mentions: In xanthine oxidase (Figure 3(a)), significant main effects of treatment and time were found. In post hoc within-group comparisons, xanthine oxidase activity significantly increased after exercise in the saline-treated group only. In post hoc between-group comparisons, xanthine oxidase activity was significantly lower in the extract group compared to the saline group, both at rest and at postexercise. In TAC (Figure 3(b)), significant main effects of treatment and time were found. In the within-group comparisons, TAC increased after exercise in both saline- and extract-treated groups. In the between-group comparisons, TAC was higher in the extract group compared to the saline group at postexercise only. In protein carbonyls (Figure 3(c)) significant main effects of treatment, time, as well as interaction of treatment × time were found. In the within-group comparisons, protein carbonyl concentration increased after exercise in both saline and extract-treated groups. In the between-group comparisons, protein carbonyl concentration was higher in the extract group compared to saline group at rest only. In TBARS (Figure 3(d)) significant main effects of treatment and time were found. In the within-group comparisons, TBARS concentration increased after exercise in the saline-treated group only. In the between-group comparisons, TBARS concentration was higher in the extract-treated group compared to the saline-treated group at rest only.

Bottom Line: Numerous studies have examined the effects of plant extract administration on redox status at rest in animals and humans but their results are controversial.Our findings indicate that the tested extract exhibits potent in vitro antioxidant properties because it scavenges the DPPH(•) and ABTS(•+) radicals and inhibits DNA damage induced by peroxyl and hydroxyl radicals.Our findings suggest that the grape pomace extract does not behave with the same way in vitro and in vivo.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Biotechnology, University of Thessaly, 41221 Larissa, Greece.

ABSTRACT
Fruits, such as grapes, are essential food of the Mediterranean diet. Grape extracts have potent antioxidant and chemopreventive properties in vitro. Numerous studies have examined the effects of plant extract administration on redox status at rest in animals and humans but their results are controversial. However, there are no studies comparing the in vitro and in vivo effects of plant extracts on oxidative stress using exercise as an oxidant stimulus. Thus, the aim of this study was to investigate whether a polyphenol-rich grape pomace extract of the Vitis vinifera species possesses in vitro antioxidant properties and to examine whether these properties apply in an in vivo model at rest and during exercise. Our findings indicate that the tested extract exhibits potent in vitro antioxidant properties because it scavenges the DPPH(•) and ABTS(•+) radicals and inhibits DNA damage induced by peroxyl and hydroxyl radicals. Administration of the extract in rats generally induced oxidative stress at rest and after exercise whereas exercise performance was not affected. Our findings suggest that the grape pomace extract does not behave with the same way in vitro and in vivo.

Show MeSH
Related in: MedlinePlus