The Antioxidant Effects of a Polyphenol-Rich Grape Pomace Extract In Vitro Do Not Correspond In Vivo Using Exercise as an Oxidant Stimulus

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•